chimp

How Specific Are The Social Skills of Dogs?

jgoldman — Wed, 16 Jun 2010 05:30:00 +0000

How Specific Are The Social Skills of Dogs?

Dogs are particularly good at tasks that involve communicating or cooperating with humans, which has led some researchers to speculate that they are really good at solving social tasks, more generally. For example, dogs can figure out where a human's attention is, are really good at picking up on eye-gaze and finger pointing cues, distinguish among different individual humans (by contrast, humans are really bad at distinguishing among different individual monkeys, for example), and at least in one outstanding case, are capable of "fast mapping."

Relative to non-human primates, domestic dogs indeed seem to have exceptional social skills. For example, previous research has demonstrated that dogs are able to use human social cues to find hidden food while non-human primates do not. Furthermore, cross-sectional studies of dogs and puppies of different ages, as well as longitudinal studies which track the development of individual puppies, have indicated that dogs do not require extensive exposure to humans to skillfully use those cues (though training enhances their skill). By contrast, wolf pups do require extensive exposure to humans to be able to extract meaning from human social cues such as eye-gaze and finger-pointing. So, while both dogs and wolves are able to understand human social cues, the domestication of dogs seems to have selected for this trait and allowed it to emerge early in development without much experience.

Figure 1: Gratuitous picture of my dog? Sure, why not?

But these studies of social cognition in dogs have had one common theme, which is that they all tested social cognition in the context of a communicative-cooperative task. But do dogs' social skills extend beyond this narrow context? In non-communicative or non-cooperative social tasks, are dogs' social skills otherwise unremarkable? The distinction is not trivial; social information comes in various forms beyond explicit communication. For example, various non-human primate species are known to alter their behavior when trying to steal food from a human, according to whether or not that human is watching them. This is surely a social problem, but one devoid of explicit communication or cooperation.

Two researchers with whom the regular reader of this blog should now be familiar, Victoria Wobber (who ran the bonobo testosterone study I mentioned in the review of Bonobo Handshake) and Brian Hare, wonder to what extent dogs can reason about the social world more broadly. Specifically, would their impressive social skills persist in a task that did not involve cooperative communication? They compared dogs and chimpanzees in two versions of a reversal learning task: non-social and social.

The reversal-learning task goes something like this: you present the individual with two containers. In one container there is a reward (like a peanut or a dog biscuit), and in the other container, no reward. If the subject chooses correctly, the reward is given; if not, the reward is revealed in the alternate location but is not given. The reward is always going to be found in the same location, so after a few trials, the participant should learn which container to choose to receive the reward. Then, once it becomes clear that the participant has learned the task (in this study, 84% accuracy), then the rewarded container switches. How quickly does the participant learn to inhibit the previously-correct choice, and begin choosing the alternative container which now contains the reward?

In the non-social condition, the reward was hidden underneath cups or bowls. The experimenter takes a treat, hides it under one of the bowls, and sham-hides it under the other bowl. Then the experimenter backs away and stares directly at the individual instead of at either of the bowls and the individual is allowed to choose.

In the social condition, instead of cups or bowls, human experimenters hid the rewards in their hands. Both experimenters went to the box of treats: the first took one and hid it in her hand, and the second only pretended to take one and hide it in her hand. Then both experimenters approached, reached out and offered their closed fists to the participant. As in the non-social condition, the participant chooses by pointing or approaching one of the individuals. This task requires that the participant form an association between one individual human and the potential reward, but does not require the participant to interpret any cooperative-communicative cues. Compared to the non-social task, this task is highly social: the participant must use social information about an individual's previous behavior to succeed.

Figure 2: Two of the Gombe chimps. (source)

It is well-known that in humans, placing an otherwise non-social problem in a social context increases performance. It is therefore possible that chimpanzees and dogs may be better able to learn when identical information is presented in a social context. Wobber and Hare describe their predictions in this way:

If neither species showed a different between the two contexts, this would suggest that the ability to inhibit prior learning is independent of the stimuli being learned. However, if chimpanzees showed increased performance in the social task, this would create two alternative outcomes for the dogs. If dogs' exceptional social skills extend beyond the use of cooperative-communicative contexts, they should show relatively more skill in the social reversal learning task than the non-social task. If, however, their skills are limited to interpreting human signals, they should show no distinction between the two tasks.

Critically, the goal here isn't two compare chimpanzees to dogs. The predictions concern within-species differences between the two tasks. In that sense, the chimpanzees serve as a control for the dogs. If the chimpanzees do not show a task-dependent difference, the data from the dogs can't really be interpreted. However, if the chimpanzees do show a task-dependent difference, then the data from the dogs is interpretable in terms of the importance of the social context.

Twenty-two chimpanzees participated as well as twenty-four dogs. Each individual participated in either the social or non-social condition, but not both. The chimp research took place at the Tchimpounga Chimpanzee Sanctuary in the Congo Republic (chimpanzee congo, not bonobo congo), and the dog research took place at the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany (all dogs were pets).

First, how quickly did the participants learn the initial association, in either condition? For both species, there were no differences between tasks in how quickly they were able to form the initial association.

Figure 3: Mean trials to reach 84% criterion in the first part of the experiment. Bars are standard error. No difference between conditions in either species.

Next, how did the participants do in the second part of the experiment, after the reward location had been reversed? There was a significant difference between conditions for the chimpanzees, with chimpanzees in the social condition performing better. There was no significant difference for the dogs.

Figure 4: Mean number of trials where the accurate choice was made. Bars are standard error.

Furthermore, when comparing the first ten and last ten trials of the reversed part of the task, it is clear that while the dogs in general improved throughout the course of the experiment, there was no distinction between the two conditions. In contrast, for the chimpanzees, there is a clear difference between conditions: they improved over the course of the experiment in the non-social task, but were near ceiling the entire time in the social task.

Figure 5: Performance across the twenty trials of the reversal. Dogs, above; chimps, below.

Taken together, the data suggest that while chimpanzees were able to inhibit their learned response in the social condition, the dogs were unable to inhibit their learned response in either condition. The social context allowed the chimps to quickly alter their behavioral response. In contrast, the social stimuli devoid of communicative-cooperative information, was not helpful for the dogs. This supports the hypothesis that dogs' exceptional social abilities are specific to contexts involving cooperation and communication with humans, not that dogs are more skilled with social problems more broadly. By contrast, chimpanzees were more successful in the social condition than the non-social condition. While dogs may be more successful when given communicative-cooperative information by humans, chimps are clearly more successful than dogs in the absence of such information.

What allowed the chimpanzees to excel in this task? It is known that chimpanzees (as well as rhesus macaques and human children) keep track of who their friends and enemies are, so it may be that they formed "reputations" for the two human experimenters in the social task. It is not yet known whether dogs do this as well.

Another possibility is that the presence of the two human experimenters in the social task was too distracting for the dogs to really perform to their potential in this task. However, neither the chimps nor the dogs differed between conditions in terms of their ability to learn the initial association, suggesting that the task was a valid measure of learning, and that both species were sufficiently motivated.

So overall while the data don't completely contradict the hypothesis that dogs have superior social problem-solving skills overall, it does suggest that their domestication has particularly enhanced their problem-solving skills in communicative-cooperative contexts. More specifically, even if they are unusually competent with social tasks in general, they seem to be especially good at social tasks involving communication or cooperation with humans.

Wobber, V., & Hare, B. (2009). Testing the social dog hypothesis: Are dogs also more skilled than chimpanzees in non-communicative social tasks? Behavioural Processes, 81 (3), 423-428 DOI: 10.1016/j.beproc.2009.04.003

jgoldman Wed, 06/16/2010 - 01:30

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Chimpanzee

communication

Comparative Psychology

dog

domestication

mammals

Psychological Science

I don't know what kind of dogs you used in this experiment, but I have a beagle, and if you are assessing how well a beagle "learns" which hand or container has a treat, you have to allow for the fact that he can probably smell the treat. The PetSmart store offers free sample dog biscuits at the register. I often put one in my pocket and forget about it. After I get home, I'll sit down on the sofa and Darwin will jump up next to me and start to sniff me and get excited. If I do nothing, he will nuzzle my hip looking for the treat. I don't know much about how his brain works, but his nose is excellent.

Great post, fascinating paper. I wouldn't have seen it without your blog - thanks.

I take issue with one thing you write, though:

It is known that chimpanzees ... keep track of who their friends and enemies are, so it may be that they formed "reputations" for the two human experimenters in the social task. It is not yet known whether dogs do this as well

It has been known since the time of Plato, who wrote in The Republic: "a dog, whenever he sees a stranger, is angry; when an acquaintance, he welcomes him, ..."

This is particularly interesting, considering that wolves and dingoes -which lack the social talents of domesticated dogs- actually are "smarter" than domestic dogs at non-social tasks. The evolutionary pressure on dogs has thus produced extraordinary results on social skills despite a more impoverished brain.

Are there breed differences in social skills or general intelligence? I (and any other dog owner, I'm sure, particularly any that go to the dog park) commonly hear that Breed X is easier/harder to train, or smarter/dumber. Are these often anecdotal assertions backed up by data? For instance, it's easy for me to say, well, I have a dog that's stubborn as hell and refuses to come when called if there's something interesting to smell and another that's very attuned to her name and 'come' but refuses to learn not to jump on people. Can you actually say one personality is due to hound genes and one to boxer genes (or possibly kangaroo), or is it all within normal variation between any two individuals, between breeds or within them?

This reminds me of a piece of research by A. Horowitz ("Disambiguating the âguilty lookâ: Salient prompts to a familiar dog behaviour") that looked at whether dogs can understand when they should be "guilty" enough to give genuine "guilty looks". Turns out they probably can't.

Thanks for the good post!

Great study, thanks for posting the findings!!

@1: In other studies, it has been shown that domestic dogs do not use olfactory information to find food and rely on human social interaction. This is not to say that they don't have a good sense of smell (certainly, some breeds were specifically bred for that purpose), just that they might not use it. And then, your dog may be an exceptional anecdote, but not data.

@2: A dog can certainly distinguish among individual humans, as I wrote, particularly acquaintances from strangers. But this is different from forming lasting reputations and predicting future behavior based on prior behavior.

@4: I've heard the same anecdotes as you. We do know that there's some data on e.g. breed personality, but I'm not sure about learning style. If you told me that personality and learning style were correlated, I'd believe you. I'll look around. My guess would be that, like most things, you'll find more within-breed variation than between-breed variation. Good question!

Great post. Wouldn't have seen the paper without your blog. Thanks!

I always find these kinds of intelligence tests interesting and I too have heard that wolves, while similar to dogs in so many ways, lack the ability to interpret the non-verbal cues that dogs do. I've seen the videos that exhibit this, with the wolf (adult wolf, I should add), whose intelligence is not doubted, just not seem to get what the human is doing by pointing or looking at the intended object, or at least not thinking it was meaningful, and I've always wondered, since dogs possess so many trait which in wolves are associated with their young, if anyone ever conducted these same experiments with young wolves who have yet to become invested in their packs instinctive social dominance drive. It would seem that an adult wolf would not benefit from being distracted by where it's packmates were staring unless there was also some other cue, but a young wolf would benefit from this kind of intelligence so that it could learn what it's other packmates were trying to convey as it learned how to be a wolf in their social structure and thereby rise and bring benefit to the pack.

Fascinating.

I had read that dogs cannot attribute motivation to other creatures, but my experience suggests otherwise.

Once, when I was playing ball alone with my dog in the park, she noticed another dog approaching from off in the distance. She took her ball, placed it by the exposed roots of a tree and looked hard at it, seeming to memorize its exact location. Before the other dog came near, mine had walked away from her ball, as if intentionally keeping it inconspicuous to the stranger who might (if like my dog) be tempted to steal it.

Jason Goldman wrote this:
@1: In other studies, it has been shown that domestic dogs do not use olfactory information to find food and rely on human social interaction.

I'd wonder about those studies. It seems such a maladaptive behaviour to have a good nose and not use it to find food. And anyway, I could tell you about the time my dog ate the wrapped chocolate bar under the christmas tree which the humans didn't know about.

But more seriously, I rather suspect that you left out some qualifications there. There may be circumstances where dogs don't use their noses to find food. Perhaps in a well-designed experiment they don't or can't, but I can hardly imagine that the blanket statement is true under all circumstances.

Is this saying that domestic dogs have developed dependent personalities and require us to stimulate or guide their brains, which have become lazy? Well I think they are no longer a fully canine creation - they've surely learnt a lot from us, and maybe lost a lot by intra-species living arrangements. Our need for them as hunt aids and protectors has kind of diminished - creating a lot of redundancy. But my dog certainly reads me like a book, senses my moves before me.

I don't know much but searched the dog IQ subject out if an emerging curiosity as to why some dogs I know are smarter as well as more prosocial and balanced than many people I know. Proof - a person with a diploma and obvious need to feel superior alleged to me dogs don't think, but only run on instinct! Well mine have often formulated complicated plans and solved complex practical and social problems.

One dog (an honest tending shepherd/greyhound) would eye up food left in an outside sleep out all day - then when someone got home from work would either lead us to it and seek consent to devour it - or bring it in its wrapper to the main house and request permission to devour it. A less honest more dare devil dog I had (GSP) figured out the day that he local Drs wife stocked up at the butcher and would hide in her bushes till her car pulled in, then as she too the first joint of meat in her house he would leap in the boot of her car and get a large meat cut eg leg of lamb, and bring it home as an offering to our household.

This occurred for months before we discovered the meat source, when we heard via gossip that the elderly Drs wife did not know who stole her meat, but figured it was a hungry person, so now allowed for a bit extra in the weekly purchase...

Funny - the dog wasn't hungry nor us the recipients of her contribution. Seems she just needed to contribute. Idols were another sign of civilisation. The dog had a sculpture of a dog it nestled up to in times of crisis like guy fawkes, and revered an older female - to the point of making long leisurely daily visits to the older dogs grave for a few months when she died (without any thought of digging as we feared), and being very distressed by the corpse (alarmed, skittish and repulsed - showing whites of eyes in horror at the older dogs fate) and by it's burial (depressed - crying tears, and turned away refusing to watch). In contrast the dog was not too concerned at my Mothers inanimate body, also lying in state alongside the beloved older dog (both killed together on a car crash).
In fact touching either after death whom he'd usually be all over was taboo to him and he kept 2 metres distant - could be a fear death is contagious? Sure was understood.

I am a dog trainer by profession and a behavior junkie. One of our dogs has already participated in Dr. Hare's study. Our other dog will participate later this month. It was fascinating to watch. I do believe that there is some differences with breeds, in that some are bread to work with people (the herding breeds) and some are bread to work alone. That being said both of our dogs are Australian Shepards and I'm certain that the results from the tests as I observed them will be very different between these two dogs of the same breed.

How Do You Figure Out How Chimps Learn? Peanuts.

jgoldman — Wed, 12 May 2010 15:15:00 +0000

How Do You Figure Out How Chimps Learn? Peanuts.

What is culture? One simple definition might be: a distinctive behavior shared by two or more individuals, which persists over time, and that ignorant individuals acquire through socially-aided learning.

There are at least four different ways to learn a particular behavior or problem-solving strategy. That is to say, there are four different ways to learn. The first is social facilitation, in which one individual does the same thing as the demonstrator at the same time. Essentially this is a situation of on-line matching of motor actions. For example, I might learn the steps to a complicated dance by watching somebody else doing it and replicating the motor actions at the same time. The second is emulation, in which the learner replicates the demonstrator's goal, without replication of the precise motor actions. If you see me climb a tree to retrieve a candy-filled pinata, you might figure out that an easier way to retrieve the candy would be to smack the pinata with a baseball bat. Importantly, you have deduced my goal from my behavior (I want candy), as well as the results (I get candy). The third is imitation in which after observing the demonstrator solve a task, the learner precisely replicates the novel motor actions, in the absence of the demonstrator. Finally, the fourth is teaching, or pedagogy in which a knowledgeable individual provides active instruction to an ignorant individual. It was through teaching that I learned how to tie a tie, for example, or to cook a steak to a perfect medium done-ness.

Video 1: Do not ever, ever, use anything other than kosher salt to season your steak. I will know. I will find you.

Since learning underlies culture, it is important to understand how different species learn, if we wish to understand the evolution of culture.

Chimpanzees, for example, appear as if they have at least some sort of culture. Among six groups of chimpanzees in Africa, for example, the different groups have various methods for throwing, inspecting wounds, inspecting parasites, and so forth. Some groups don't show evidence of those behaviors at all. These behaviors are not species-specific, and instead appear to be group-specific. In other words, a basic form of culture.

Figure 1: Some evidence of culture in chimp groups.

However, when you see a population of individuals doing the same thing, it is a mistake to assume that they acquired the behavior in the same way. For an analogy from biology, consider eyes. Both mammals and cephalopods have eyes, but they evolved separately, and are morphologically distinct. Likewise, just because two groups of chimps (or people) show similar behavior does not mean that they came about the same way, or are constructed of the same cognitive building blocks.

How do you figure out how individuals acquire novel behaviors? A paper that was published today in the journal PLoS ONE describes one method: Peanuts.

Figure 2: No, not that kind.

Figure 3: Yup, that kind.

Chimpanzees really like peanuts. Here's the plan: create a long clear tube, and drop a peanut into it. Bolt it to a chimp cage, so that the ape will have to get creative to retrieve the tasty snack. Have some chimpanzees spontaneously figure out how to get the peanut. The only possible solution is to suck water into your mouth, and spit it into the tube. Over and over again, until the peanut floats to the top. Success. Reap your nutty reward. Ignore the fact that your nuts are soggy.

The researchers did this with thirty-one socially housed chimps, in two different locations. Some of them came from the Ngamba Island Chimpanzee Sanctuary in Uganda, and some lived in the Wolfgang Kohler Primate Research Center in Leipzig Zoo.

Most of the chimps were unable to spontaneously come up with the correct solution, but a few were.

Now comes the experiment.

In one condition, subjects watched four to six successful demonstrations of the solution by another chimp. The subject and demonstrator were always in the same cage, allowing the subject to approach and closely inspect the process. The demonstrator was always dominant to the subject, so that the subject would watch but not interfere. In this condition, subjects could invent the solution spontaneously, they could copy the actions of water spitting (imitation), or they could copy only the results of the demonstrator's actions (emulation).

Figure 4: Schematic of condition 1.

The second condition was identical, except for the following: A solution-naive but dominant conspecific "stooge" chimp was used as the social partner in this condition. The experimenter demonstrated an alternative solution to water-spitting, by pouring water into the tube from a bottle from outside the cage. The dominant "stooge," by virtue of being dominant, still gets the peanut. In this way, the conditions are identical except for the method by which the dominant chimp gets the nut.

Figure 5: Schematic of condition 2. One wonders if the experimenters were really wearing what appear to be plaid pajamas.

In this condition, the subject was able to witness the results producing the solution - adding water to the tube - but without any specific actions that the subject could mimic to solve the task. They could spontaneously come up with the solution, or they could emulate (but not imitate). Therefore, the key difference between conditions 1 and 2 is whether or not the chimp can use imitation.

Both experimental conditions showed significantly more successes than in the baseline condition (in which the only way to solve the problem was spontaneously inventing the solution). Five subjects solved the problem in condition 1, and three in condition 2. Subsequent analyses indicated that successful subjects were not successful by virtue of being more motivated, though successful individuals were younger than unsuccessful subjects. There were no differences between the two groups from Uganda and Leipzig. Further, there were no significant differences between the two experimental conditions. So, the demonstrations of condition 1, which included three types of information - actions, goals, and results - offered no advantage over the demonstrations of condition 2, which only included two types of information - results and goals.

Since action information did not provide an advantage, the best interpretation of these results is that the successful chimps used emulation learning to solve the task. Is it therefore possible that copying of goals and results, and not action, could underlie cultural traditions in apes? That does seem to be the best explanation, given these findings, which is also consistent with previous findings in which apes ignored superfluous actions and only imitated relevant actions to retrieve a reward. This also provides a reasonable explanation for the variation among chimp groups in Africa, each with slightly different solutions to their problems.

The finding that younger chimps were more successful than older individuals is also consistent with previous findings. The age of the successful learners (4-6 years) coincides with the age at which chimps are observed using tools in the wild. In fact, primate researcher Michael Tomasello (who was one of the authors of this paper), has previously suggested that there may be a sensitive period underlying the ability of chimps and other apes to use tools, much like the sensitive period for learning language in human children. This would explain why the older subjects in this and other studies failed to successfully solve the peanut problem, even after social demonstrations.

One other implication of this paper is important to mention, and that is the social nature of this learning. Previous studies have done experiments very similar to condition 2, in which the learner watched a human fill the tube with water to make the peanut float, but without another conspecific present, and in those experiments, apes tend to be unsuccessful in learning the solution to the problem. While in this experiment, results and goals were sufficient to learn the task, it may be that the results themselves are not what is driving the pattern. Instead, perhaps it is the addition of the goal-related information from the social partner (getting to eat the reward) that allows for successful emulation, making social information critical to emulation learning.

Tennie, C., Call, J., & Tomasello, M. (2010). Evidence for Emulation in Chimpanzees in Social Settings Using the Floating Peanut Task PLoS ONE, 5 (5). DOI: 10.1371/journal.pone.0010544

jgoldman Wed, 05/12/2010 - 11:15

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why 'only possible' instead of 'most convenient solution'?
Do chimps ever carry water with cupped hands?
Find something to soak up water and deliver it?
They could even urinate in the tube.

Do chimps ever carry water with cupped hands?

I'm not sure, but even so, the water bottles that were available to them in their cages would not have allowed this; the water has to be sucked out of the bottles. I suppose they could conceivably suck the water out, spit it into their hands, and pour it into the bottles... though none of them ever did that, and its not really fundamentally different from the solution that the successful chimps did use.

Find something to soak up water and deliver it?

The experimenters made sure that there were no other tools available in the cages. Also, see above re: water bottles.

They could even urinate in the tube.

I suppose that's true. But, then, would you want to eat a peanut floating in urine?

Scientists tickle apes to reveal evolutionary origins of human laughter

edyong — Thu, 04 Jun 2009 10:00:23 +0000

Scientists tickle apes to reveal evolutionary origins of human laughter

If you tickle a young chimp, gorilla or orang-utan, it will hoot, holler and pant in a way that would strongly remind you of human laughter. The sounds are very different - chimp laughter, for example, is breathier than ours, faster and bereft of vowel sounds ("ha" or "hee"). Listen to a recording and you wouldn't identify it as laughter - it's more like a handsaw cutting wood.

But in context, the resemblance to human laughter is uncanny. Apes make these noises during play or when tickled, and they're accompanied by distinctive open-mouthed "play faces". Darwin himself noted the laugh-like noises of tickled chimps way back in 1872. Now, over a century later, Marina Davila Ross of the University of Portsmouth has used these noises to explore the evolutionary origins of our own laughter.

Davila Ross tickled youngsters of all of the great apes and recorded the calls they make (listen to MP3s of a tickled chimp, gorilla, bonobo and orang-utan). She used these recordings to build an acoustic family tree, showing the relationships between the calls. Scientists regularly construct such trees to illustrate the relationships between species based on the features of their bodies or the sequences of their genes. But this is the first time that anyone has applied the same technique to an emotional expression.

The tree linked the great apes in exactly the way you would expect based on genes and bodies. To Ross, this clearly shows that even though human laughter sounds uniquely different, it shares a common origin with the vocals of great apes. It didn't arise out of nowhere, but gradually developed over 10-16 million years of evolution by exaggerating the acoustics of our ancestors. At the very least, we should now be happy to describe the noises made by tickled apes as laughter without accusations of anthropomorphism, and to consider "laughter" as a trait that applies to primates and other animals

Altogether, Davila-Ross recorded the laughs of 3 human babies, 7 orang-utans, 5 gorillas, 4 chimps, 5 bonobos and 1 siamang (the largest of the gibbons). All of them were playfully tickled by friendly humans in their home environments and on their palms, feet, necks or armpits. Two independent researchers carefully analysed each recording, noting their pitch and timing across 11 different measures. They compared how long the calls were, how many were made, how high-pitched they became, and more.

Her phylogeny of tickled laughter exactly matches the known relationships between the apes - human laughs are most closely related to those of bonobos and chimps, less similar to those of gorillas and most distinct from those of orang-utans and siamangs.

Laughter is very much an instinctive part of human life. Babies who are born deaf can still laugh, and deaf people will laugh while using sign language in the same places that speakers would do. Davila-Ross's study suggests that this innate behaviour has deep evolutionary roots and arose by exaggerating traits found in apes. For example, our laughs are "voiced", meaning that they are made by vibrations of the vocal cords. Among the other apes, laughter usually takes the form of unvoiced noises like huffs and pants, although bonobos did occasionally made voiced calls.

Humans also only ever laugh while breathing out, while other apes can laugh twice on every breath, during both the exhale and the inhale. Chimps, in fact, laugh almost exclusively in this alternating style. Humans compensate for this restriction by being able to exhale a steady flow of air for much longer than a normal breath cycle, a vital ability that lets us speak properly without continually having to catch our breath. Some scientists had thought of this as a uniquely human ability, but the tickle sessions clearly show that gorillas and bonobos can both sustain an exhalation for 3-4 times longer than their normal breath cycle.

The figure below represents Davila-Ross's take on the evolution of laughter. She imagines that the last common ancestor of the apes had a primordial laugh that was longer and slower than ours, consisting of short bursts of noisy calls with little variation between them. Both voicing and long, steady exhalations evolved well before our ancestors split away from those of bonobos and chimps. The rest of our vocal characteristics are just subtle tweaks of those of apes. Of course, this research tells us nothing about why these particular properties developed in the way they did, and what they meant for the evolution of laughter as a means of communication. That will have to wait for future studies.

Reference: Current Biology DOI 10.1016/j.cub.2009.05.028

Images, sound files and videos courtesy over University of Veterinary Medicine, Hannover.

More on apes:

edyong Thu, 06/04/2009 - 06:00

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Male chimps trade meat for sex

edyong — Wed, 08 Apr 2009 05:30:15 +0000

Male chimps trade meat for sex

Many men think of little else besides sex and meat, but male chimpanzees will sometimes exchange one for the other. Chimps are mostly vegetarian but they will occasionally supplement their diet by hunting other animals, especially monkeys. Males do most of the hunting, but they don't eat their spoils alone - often, they will share the fresh meat with females, even those who are unrelated to them. Some scientists have suggested that this apparently selfless act is a trade - the males are giving up their nutritious catch in exchange for sex.

Cristina Gomes and Christophe Boesch from the Max Planck Institute for Evolutionary Anthropology have found new evidence to support this idea. They spent four years in the Tai National Park in Cote d'Ivoire watching a group of 49 chimps, including 5 adult males and 14 females. They recorded a huge amount of data on the group's behaviour, and across 3,000 hours of observation, they were privy to 262 bouts of chimp sex.

These years of voyeurism told them that meat was a big factor in separating the Casanovas from the sexually frustrated males. Females mated more frequently with males who gave them meat at least once, and meat-sharing was much more important than other shows of support such as grooming, sharing other types of food or taking their sides in fights. None of these other actions had much bearing on the male's sexual success.

Gomes and Boesch wonder if human hunter-gatherers rely on similar trades. That's certainly been suggested before, especially since better hunters tend to have more wives (or at least, more affairs). These results do nothing to confirm or deny that idea, but they certainly provide strong evidence that chimps, at least, are indeed exchanging meat for sex.

There are, of course, other possible explanations for the data. It's possible that dominant males get the lion's share of meat after a kill, and tend to monopolise the females. It could be that the most sociable females would be most likely to receive meat and to mate with males. It's even possible that females who mate most often with a male then harass him strongly for meat.

Gomes and Boesch ruled out all of these options by statistically adjusting their results for the social status of both partners, how often the partners interacted with each other, and how often the female begged for meat from the male. It was a challenging task but at the end of it, they found that the link between meat-sharing and sex was still significant - it was unlikely to be a statistical blip, and it couldn't be explained away by any other explanation they could come up with.

After all this mathematical fine-tuning, the duo estimated that males can doubled their chances of mating by sharing meat. After they do it once, it seems that there's little benefit in doing it more, for females don't make a distinction between males who give them small pieces, and those who serve up large slabs of monkey steak.

Males tended to slightly focus their attention on females during oestrus, the part of their sexual cycle when they are most fertile and sexually receptive. But even when Gomes and Boesch focused on exchanges between males and females outside of the oestrous phase, they still found a strong link between meat-sharing and mating frequency.

This suggests that the donation of meat doesn't just reward males with immediate sexual gratification; it has much longer-term benefits. As is becoming increasingly apparent, the chimpanzee is an animal that can think about, and plan for, the future. Certainly, if they can gather ammo to throw at tourists, they can donate some meat to barter for future matings.

Reference: Gomes, C., & Boesch, C. (2009). Wild Chimpanzees Exchange Meat for Sex on a Long-Term Basis PLoS ONE, 4 (4) DOI: 10.1371/journal.pone.0005116

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edyong Wed, 04/08/2009 - 01:30

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Interesting study, and as an archaeologist I find it worthy of consideration. There is but one thing that keeps bugging me with the interpretations that many researchers (and the public) jump at when studies like this are published: It is almost immediately assumed that it has direct bearing in human development. But humans did not develop from chimpanzees - we both evolved form a common ancestor.

How can we be sure that any particular trait discovered in chimpanzees belong to the traits that played an important part in the development if humanity? Could it not just as easily be the other way around - one way in which we are different, and it therefore explains something about why chimp society and human society are different?

For instance, social interaction is of crucial importance among humans. Could it be that one thing that developed differently for us is that our ancestral females couldn't be swayed by the gift of a raw steak now and again, but demanded greater continuing care and assistance in things great and small from their males?

This is a very difficult paradox in the study of primates. We are similar, we know, but how are we dissimilar!?

That's only because they haven't yet figured out how much better liquor works. ;-)

Yeah, I like this paper. Goes to show that the "oldest profession in the world" really is the oldest profession in the world. :-)

Craig Stanford wrote about this 10 years ago, as did Sagan in Shadows of Forgotten Ancestors

As a long term strategy rather than for short term favour with oestrous females?

How about the notion that the females LIKE unselfish males? Or that chimp sex is one part of friendly (for lack of a better word) bonding instead of a commodity in itself to be bartered?

Oh, of course not. That doesn't fit standard evo-psych backward rationalizations for human sex role garbage. My mistake.

Cara, why don't you read the literature and decide then? It's to a female's advantage to be protected. If you knew how often chimps have sex, you would have to rethink your e-p comment. Craig Stanford makes this observation on p 69 of The Hunting Apes: "Why should we think that cooperation is a more highly evolved art form than selfish manipulation?"

Cultured chimps pass on new traditions between groups

edyong — Sun, 05 Apr 2009 09:00:19 +0000

Cultured chimps pass on new traditions between groups

For humans, our culture is a massive part of our identity, from the way we dress, speak and cook, to the social norms that govern how we interact with our peers. Our culture stems from our ability to pick up new behaviours through imitation, and we are so innately good at this that we often take it for granted.

We now know that chimpanzees have a similar ability, and like us, different groups have their own distinct cultures and traditions.

Now, Andrew Whiten from the University of St Andrews has published the first evidence that groups of chimpanzees can pick up new traditions from each other. In an experimental game of Chinese whispers, he seeded new behaviours in one group and saw that they readily spread to others.

Many animals have their own cultural traditions. Songbirds, for example, copy their parents' melodies, and small variations lead to groups with different dialects. But chimpanzees have by far the richest cultures so far observed.

These scope of their culture first came to light in 1999, when Whiten, together with Jane Goodall and others, carefully documented at least 39 cultural behaviours among wild chimpanzees. Many of these were a matter of course in some populations, but completely absent in others.

Some groups use sticks to extract honey, others use them to retrieve marrow from bones, and yet others use them to fish for ants. Some get attention by rapping their knuckles on a branch, while others noisily rip leaves between their teeth. Some groups even have a rain dance.

Whiten has previously published three studies which demonstrated different sides of chimp cultural transmission. The first showed that trained individuals can spread seeded behaviours within a group. The second showed that cultures trickle through the generations as parents teach their children new behaviours. And the third showed that arbitrary conventions such as gestures and displays can spread as easily as skills involving tool use.

Now, together with an international team of researchers from the University of Texas and Yerkes National Primate Research Center, including primate expert Frans de Waal, Whiten has produced the first experimental evidence that cultural transmission can happen between different groups.

Whiten worked with six groups of captive chimps, each consisting of 8-11 individuals. They lived in large but separate enclosures arranged in two rows of three and each group could observe its neighbours, but not interact with them.

Whiten trained one chimp from groups one and four to solve two difficult tasks - the 'probe task' and the 'turn-ip' task - in order to get some food hidden inside a box. Each chimp was taught to use a different technique.

In the probe task, the chimp could move a lever at the top of the box to open a hatch, and use a stick to impale the food (A). Alternatively, it could use another lever at the side to lift an opening, giving it enough room to manoeuvre a stick inside and push the food out (B).

In the turn-ip task (C), food items were dropped down a pipe, where they were blocked by a disc. The disc had a hole in it, that would allow the food to fall through when it was properly aligned. The chimps could turn the disc either by rotating an exposed edge or using a ratchet. Once the food dropped through, the chimps could get at it by pressing or sliding one of two different handles.

Once the student chimps had mastered their new methods, they were returned to their respective compounds and the whole group was allowed to try its hand at the tasks. Before the training, none of the chimps managed to successfully get at the food. But after just one chimp was taught the technique, most of the others in the group quickly picked it up.

The boxes were then moved to a different position, where chimps from the second pair of groups could watch chimps from the first pair solving the task. After a time, it was moved to another position where the third pair of groups could watch the second one.

Whiten found that the techniques were accurately and quickly transmitted between the different chimpanzee groups. His experiment clearly shows that chimps have an immense capacity for learning new behaviours from their peers. They do this accurately and different groups can acquire and maintain several varied cultural traditions.

In light of this evidence, the regional behaviour patterns seen in chimp groups across Africa are, without a doubt, the result of cultural transmission. In the wild, rival groups are often hostile towards each other and it is unlikely that chimps sit down in jungle conferences to share new ideas. But females do move between groups and Whiten believes that they carry new cultural traditions with them.

How exactly the new behaviours spread is still a matter for debate. Some scientists have suggested that the chimps learn by 'emulation', meaning that they focus on the results of actions rather than the actions themselves. But other studies found that chimps don't respond to 'ghost' lessons, where task machinery is operated by remote and not by another chimp.

The most likely explanation is that chimps imitate the actions of other chimps and are very good at learning from each other. In all likelihood, the common ancestor that we share with chimps had the same ability, and also had strong cultural streams running through its populations.

Reference: Whiten, Spiteri, Horner, Bonnie, Lambeth, Schapiro & de Waal. 2007. Transmission of multiple traditions within and between chimpanzee groups. Current Biology 17: 1-6.

Images: Image of experimental apparatus taken from Cell Press.

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edyong Sun, 04/05/2009 - 05:00

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Sounds pretty simple to me, monkey see, monkey do, short term memory to long term memory, and wala.

Kids' culture is transmitted the same way. Individual kids watch others at play to get a sense of the mood as well as the particular game and then join in. That's one of the skills that are commonly missed by socially awkward kids who join in without first observing and imitating.

So... Monkey sees monkey do, so monkey do?

Social inheritance isn't that new - ethologists, evolutionary biologists and philosophers of biology have studied it for quite a while. In fact, it's majorly important for evolution in general

I think Jablonka & Avital (in "Evolution in four dimensions" and "Behavioural Inheritance") have got it almost right in identifying four inheritance systems in nature: genetic, epigenetic, behavioural and symbolic.

Sadly though, the gene-centrism rampant since the triumph of molecular genetics means that this centrism is what is presented to the public and to students - talking about non-genetic inheritance and nongenetic factors of evolution is almost treated as heresy among some (not all, fortunately).

But it's not that hard to see how behavioural inheritance can shape evolution - the best and most abundant evidence being improvements in foraging-behaviour.

I'm sure many of you have read about the group of bottlenose-dolphins where some females had developed a way to use sponges to increase the ease and efficiency of searching for food and preparing it for ingestion, and that this behaviour is passed on vertically (from parents to offspring) among the females.

Now suppose that (as is quite evident) this behaviour actually increases the availability of nourishment for those adopting the behaviour - this lessens selection-pressure on those adopting it (and perhaps non-participating benefactors) - voila, the behaviour is selected for. Perhaps this increase in efficiency allows for larger group-sizes and/or an increase in habitat-area - leading to a new, improved (from the dolphins' point of view) stable relationship with a redefines (broader) environment... A change in the ecosystem brought about by variation and selection - i.e. evolution.

However, successful imitation learning requires quite a bit of cognitive effort, and as such is not the most basic, most easily employed way of behavioural inheritance. Cue-driven behaviour on the basis of templates often suffices for behavioural inheritance - for example, there is a group of rats living (unusually) in a forest and feeding (unsually) on seeds from cones. The latter is unusual because prying the seeds from the cones isn't easy - in fact it is so hard that no rats have been observed to be able to do it without having inherited the behaviour.

People were quick to posit imitation-learning as the factor behind this, but as it turned out, things were a little different: Mother rats began to work on the cones in their established spiral pattern, but stopped some way through, allowing their offspring to try themselves. They begin tracing the biting-pattern of the mother, following the biting-marks the mothers leave (simple cue-driven feeding behaviour) - and thus, in virtue of the feeding-attempts initiated by cues and the pattern that the template cone forces/guides them to employ, they inherit the behaviour without imitation learning, that is observation and mimicking.

However, in opposition to Jablonka & Avital, I would refrain from using the word culture in that context. Behavioural inheritance through imitation-learning and template-learning (and perhaps in other ways) is social, but not cultural.

We get a more fine-grained and useful distinction (that, as a bonus, can also apply the distinctively human aspects of social living) by only applying the predicate 'cultural' where actual, generationally stable 'externalization' happens, i.e. the production of cultural artifacts - modifications in the environment that fulfill generationally stable roles, i.e. that allow new generations to inherit complex behavioural schemata and integrate them into complex social phenomena by simply being shaped by the environment - without specifically having to learn everything through personal learning.

In any case - the dogma that every evolutionary relevant trait is inherited only through the Weissmann-bottleneck of the genes is blatantly false. This in no way detracts from the success of molecular genetics - it just shows that not everything can be usurped by it.

The literature on this is fascinating - and only through recognizing these inheritance systems can we begin to develop a real explanation for the huge difference between the complexities of human lives and that of any other animal... science, poetry, philosophy, discussions, governments, technology, uncounted social roles and empirically constitutable differences in them between people....
...sadly, many simply close their eyes to the severity of these differences because it doesn't fit into the gene-centristic view and the dogma that evolution has to be smooth so there can be no drastic differences.

Thankfully, through learning to understand behavioural and social inheritance we can begin to understand how all this fits perfectly in the theory of evolution. We can understand how language, cultural inheritance and the neuronal density and complexity of connectivity in the neocortex specifically can account for the distinctively human aspects of sociality and culture, and how language is the main catalyst for cultural evolution, explaining the evolutionary possibility for the emergence of the above mentioned distinctive aspects.

Of course, once complex social functions and social inheritance emerge in populations, ther IS a benefit for mutations that increase the efficiency of neocortical activity, as this will allow better and more flexible adaption to these social constructs, which can arise and persist even without flexible, intelligent cognition.

Still, many of those studies on animal cognition and sociality are to be taken with a grain of salt... often, interpretative inferences are made that are neither parsimoneous nor neuroscientifically plausible.

Interestingly, evolutionary theory and animal cognition-research is something where philosophers of biology have contributed majorly, where a synergetic cooperation of biologists and philosophers has helped to uncover many problems with widespread definitions of fitness and selection and with the aforementioned interpretations. Of course a good number of biologists were always careful enough to avoid the pitfalls of unparsimoneous and physiologically implausible inferences. Sadly, many biologists still ignore the contributions of philosophers, contributions which those biologists who do make the effort to understand them recognize as important and fruitful.

In any case, if you're interested in this sort of thing (social inheritance, culture etc) , I'd recommend the following literature:

Jablonka & Avital - Behavioral Inheritance
" " - Evolution in Four Dimensions
Boyd & Richerson - The Origin and Evolution of Cultures
M. Tomasello - The Cultural Orgins of Human Cognition
Hurley & Nudds - Rational Animals?

and for imitation learning and its neuroscientific basis, I'd recommend

Hurley & Chater - Perspectives on Imitation - From Neuroscience to Social Science

and in case anyone should be doubtful about or interested in the import of philosophy to evolutionary biology - the Stanford Online Encyclopedia of Philosophy has several highly interesting articles that show the relevant conceptual problems that give the issues in question a strong philosophical dimension, most notably with such concepts as fitness and selection:

http://plato.stanford.edu/entries/fitness/
http://plato.stanford.edu/entries/natural-selection/
http://plato.stanford.edu/entries/teleology-biology/

They also have a general article on philosophy of biology...

Anyway - great post. It's time more people read about social inheritance!

Abb3w - precisely.

"So... Monkey sees monkey do, so monkey do?"

Actually.. this needs a little modification.
Ape sees ape do, so ape do!

Chimpanzee collects ammo for "premeditated" tourist-stoning

edyong — Mon, 09 Mar 2009 11:00:14 +0000

Chimpanzee collects ammo for "premeditated" tourist-stoning

In 1997, Swedish inspectors found several stockpiles of missiles hidden in a local zoo. Apparently, the arsenal had been gathered together for the express purpose of being used against civilians. And who was the mastermind behind this collection? A 19-year-old chimpanzee called Santino.

Santino was born in a German zoo in 1978 and transferred to Furuvik Zoo at the age of 5. To this day, he lives in the zoo's chimpanzee island - a large outdoor enclosure surrounded by a moat. Throughout his residence, he was mostly docile towards the eager visitors, but all of that changed in 1997 when he started chucking disc-shaped stones at them.

Now many of us may have secretly wanted to take part in a spot of tourist-stoning, but Santino's antics became so common that visitors were actually in real danger. The zoo staff had to take action. One morning, they swept the chimpanzee island and (unlike some other weapons inspectors) they actually found Santino's arsenal - five separate caches of stones dotted along the shoreline facing the public area. Each one contained 3-8 missiles including concrete slabs, and algae-covered stones that had clearly been taken from the moat.

Mathias Osvath from Lund University, who describes the behaviour in a new paper, believes that it's clearly premeditated. Until now, it's been very difficult to work out if natural chimp behaviour involves true forward-planning or represents a reaction to present circumstances. Is a chimp that gathers twigs for termite-fishing planning for the future, or just responding to a more immediate hunger?

There's no easy answer to that, but Santino's case is much clearer. One of his caretakers, Ing-Marie Persson has collected plenty of evidence to show that he was deliberately stockpiling weapons of individual destruction for future acts of tourist-stoning.

When the stone-throwing was first noted, Persson spent five days in a room overlooking the chimpanzee island to observe Santino's behaviour. On the first morning, before the zoo opened to visitors, he gathered several stones from the moat and stacked them on discrete spots on the bank.

As the afternoon arrived, and the crowd with it, Santino grabbed ammo from his piles and threw them at the visitors. The caretakers rushed to warn the crowd and usher the chimp inside, but not before he'd managed to lob all of his missiles across the moat. He did the same thing over the next four days, and this time, caretakers were positioned in the visitor's area to warn the unwitting targets not to get too close to the rocky "hail storms".

Since then, the caretakers have removed hundreds of ammo caches and a year later, they found that Santino had started upgrading his ammunition. Not content with gathering stones, he had started to add concrete blocks to his arsenal. He even manufactured these himself by gently knocking on concrete rocks in the centre of the island. When he heard hollow sounds that betrayed the presence of cracks, he pummelled the rocks more vigorously until pieces broke off.

Based on these observations and interviews with the zookeepers, Osvath thinks that Santino's aggression was clearly premeditated. He was always visibly agitated when he threw his stones, as indicated by his two-legged loping walk and his hair standing on end. In contrast, he was always calm during the "planning stage" when he actually gathered stones - he wasn't just doing it in response to any immediate desire. The two behaviours were also separated by several hours and Santino only ever gathered ammo before the zoo opened to visitors, so no human could have provoked his ire.

The stones were very clearly an anti-human weapon. Santino never used either stones or concrete slabs for any other purpose other than to pelt tourists. He never chucked them during the six off-season months when the zoo is closed to the public. And he only ever placed them on the shoreline facing the visitors' area, a sector comprising less than a quarter of the island's full circumference.

Osvath admits that he had to rely on an "unorthodox choice of methods" for this study, given that the keepers were ethically obliged to protect the zoo visitors from the risk of thrown stones. Despite this constraint, he still managed to accumulate a large amount of data that demonstrates the remarkable intelligence of the chimpanzee.

Santino is an advanced tool-maker, learning to create concrete missiles through its own initiative. And what's more, he showed the ability to plan for the future based on a predicted state of mind, rather than the one he was currently experiencing. A few studies have reported that chimps, orang-utans and scrub jays can plan for the future, but all of these involved behaviours learned in an artificial laboratory setting. Santino's stone-throwing antics, on the other hand, were completely spontaneous.

Reference: Current Biology to be published in 10 March issue

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edyong Mon, 03/09/2009 - 07:00

Yes, sapients are often aggressive. Also there is the octopus that recently caused multimillion dollar damage at an aquarium. Does Santino not have a mate, clan, or children to attend to? This violence may stem from too much free time. Another few questions: Is he an alpha male? Where is he in the clan hierarchy? His he abused by other chimps? Does he show similar disdain to his fellow chimps? Does he live alone?

kleer001: All of that might be interesting to folks who have to actually deal with Santino, but the point of the article -- and what's interesting here -- is not that chimps can be aggressive, it's the clear evidence of prior planning.

Scott's right, of course, but since you ask, here's more on Santino:

Santino, the male chimpanzee described in the report, was born in 1978 at Munich Zoo in West Germany. He was transferred to Furuvik Zoo in Sweden at the age of 5. He spent the 5-month quarantine period with a keeper, Ing-Marie Persson. He was then introduced to a group of chimpanzees. This consisted of 5 individuals: 4 females and 1 male. Two of the females and the male were the same age as Santino, and 2 females were adults. Another chimpanzee roup was visible from the compound housing Santinoâs group. This group, including an adult male, 2 adult females and infants, was present for the first 4 years of Santinoâs residence.

Over the years, the composition of Santinoâs group varied, ranging between 4 and 7 individuals of mixed sexes and ages. When Santino became the dominant male at the age of 16, there was only 1 other male in the group. This male died within the first year of Santinoâs dominance, leaving Santino as the sole male. Soon after this, the occasional stone throwing began. Stone throwing or other stone manipulations had not been observed in Santino or the other individuals in the group prior to Santinoâs establishment of dominance. When Santino began to cache stones, he had been the only male in the group for 2 years. His behaviour has not been copied by the females, who seem to show little interest in the stone caches and concrete disc manufacturing.

No hint that the octopus was being aggressive, either, just it's normal exploratory behavior, so no pre-meditation there :-)

Having worked with chimps and orangutans, I am not surprised at all that this was finally supported by study. I am willing to say that no person that has worked with these animals would be surprised.

side

Does this mean concrete is now classed as a 'dual use technology' in the chimp-captivity world?

Lol @ Frank.

"Bad Santino! Bad! You were only meant to use your powers for good!"

Put yourself in the place of this chimp. Any crowd of staring bipeds is a threat to me. Counter that threat by a warning to leave. I bet the chimp stands, hoots and gestures at the bipeds in an attempt to communicate discomfort at social aggression on part of stupid bipeds. Stupid staring bipeds don't leave his territory. Throw something heavy enough to physically contact stupid staring bipeds. How is this zoo educating the human public or conserving this non-human species?

Before anyone goes off on one about chimps in zoos, please consider that Ing-Marie Persson from Furuvik, who observed Santino's behaviour, is the chairperson of the Swedish Chimpanzee Trust, an organisation dedicated to the conservation of chimps and orang-utans. She also represents the Jane Goodall Institute and the Sumatran Orang-utan Society.

The Daily Mash, as ever, has a brilliant take on this. Now obviously the bit about him being captured is rubbish (he was born in captivity), but the rest of the spoof article is hilarious. Especially the last paragraph:

"Interestingly Santino also displays the distinctly unhuman characteristic of having some kind of vague plan and at least trying to think it all through, instead of just making it up as you go along until even the fucking banks run out of money."

The article can be found here, access required for more than the abstract.

I wonder if he started throwing stones because somebody threw some stones at him or if he thought it up completely on his own.

The "Uplift Wars" have begun!

Amazing stuff. Thanks, Ed.

This article in the Guardian has more detail on how they dealt with this problem:

http://www.guardian.co.uk/science/2009/mar/09/chimp-zoo-stones-science

The zookeepers recently decided that an operation was the best way of controlling Santino's behaviour.

"They have castrated the poor guy. They hope that his hormone levels will decrease and that will make him less prone to throw stones. He's already getting fatter and he likes to play much more now than before. Being agitated isn't good for him," said Osvath.

This makes me kinda squirmy (and not just in the visceral "guy" way), but it's hard to think of a good solution for a raised-in-captivity chimp in a situation like this.

Thoughts, anyone?

premediated?? get real. no way a great ape could think like that.

At the first international environmental enrichment conference held in Portland, OR, years ago, I heard about some captive dolphins who cached things they found in their pool. They had learned that the keepers would trade them goodies (fish?) for retrieving items that fell in the water, so they started their own "savings account."

And also as someone who works with great apes, I am not the least bit surprised to learn about Santino's behavior. But I am appalled that the zookeepers would castrate as a way of controlling him.

Apparently he can only throw underarm, I would be certainly in favor of training him to throw with the much more powerful over arm/round arm style. Those pesky humans should be sent packing.

When I was a tourist in Sweden in 2002, I wish I'd known how easy it was to get stoned at the Furuvik zoo; the flight from Stockholm to Amsterdam was not cheap and neither were the products once I got there.

But how good of an arm did he have?

Given that chimpanzees are better than humans at just about every other physical activity (apart from speaking and swimming), I wonder how much evolutionary pressure stone-throwing had on us.

He might want them to go away or just to see them react. I wonder how he'd like it if the zoo staff gave him some tennis balls to throw.

Great explanation, Ed! I'm going to link to this.

I watched a black-faced macaque at the National Zoo and Aquarium in Canberra manufacture and use a tool, back in 2001 or so. I even saw it try and discard one attempt at doing so before settling on something different, that worked better. It blew away those lingering "God made humans special and unique" ideas I had from a christian upbringing.

I wouldn't like it if people - often rude and obnoxious - invaded my space and oggled at me every day either. Has anyone been to zoos lately? By FAR the most ill-behaved animal one will encounter are amongst those on the other side of the exhibit barriers.

Nobody can blame Santino for having a sense of civilized decency and outrage at its lack. The poor guy doesn't like it and he wants no part of it. All he wants is his little space to live out the rest of his life in peace. He's not antisocial or some violent psychopathic maniac. He's just fed up.

With US.

I mean, come on! Just look at that one photo with all those people staring in on him! He can't stand it! Neither could any of us in his position.

It is incredibly shortsighted of the zoo to they take his rocks away from him. To take that priviledge away from him is yet another cruel and "inhumane" insult that undoubtedly pisses him off all the more. They are turning what was a chimpanzee with normal chimp behavior into a grump whose every thought is how to lash back at his oppressors.

If people want to spy on him at close range, perhaps they should be issued riot gear for a modest rental fee. At least Santino can continue to keep some measure of his dignity and gain some gratification from hurling rocks at them, and the zoo can offset some of the expense of his upkeep from the proceeds.

Once again, the question looms: What the heck do we think we are we doing?

Beware! This is how it starts... next thing you know: Planet of the Apes.

The zookeepers recently decided that an operation was the best way of controlling Santino's behaviour.

"They have castrated the poor guy. They hope that his hormone levels will decrease and that will make him less prone to throw stones. He's already getting fatter and he likes to play much more now than before. Being agitated isn't good for him," said Osvath.

Is that for real? So the chimp demonstrated some remarkable abilities, and humans thought the best way to deal with that was to extinguish them. Why am I not surprised?

Joseph,

This is precisely my answer to the question of why apes have not evolved to be more like us: We'd never let 'em!

We barely let "primitive" societies have a chance at evolving, what chance for "primitive" intelligences?

Unless we are selecting against intelligence in chimps (i.e. killing the smart ones), what does taking away tools have to do with their evolution, if random genetic variation and natural selection is all that is happening?

Manual trackback:

http://backseatdriving.blogspot.com/2009/03/santino-planned-for-his-own…

"Ed Yong caught the crucial issue regarding the zoo chimp that calmly collected and made stone missiles to throw at visitors that would come to the zoo later....I haven't seen other reports about Santino discuss this issue - he didn't just plan for the future but did so with a self-awareness of what his future state of mind would be."

My gosh, the assumptions. The flippin chimp was bored, as kids we threw rocks at everything, even eachother. Future state of mind?, egads!, if you had fun throwing stones one day why wouldnt it be just as entertaining the next day.

Snowball fights, we would spend hours building the fort, and then we would make a cache of snowballs in preparation for the big fight.

As adults, we throw lead and steel propelled by explosives at one another. Many humans have a few guns and a cache of ammo in our very homes, just like this guy.

After being caged for like ever, he found something else to do to break up the monotony of his long caged days.

I've been to the zoo and looked at these poor buggers sitting around in zoo jail. They are a sad lot indeed.

One of my fondest memories was of watching my boisterous 4 year old nephew scream "MONKEY", at the top of his lungs while watching the chimp at the zoo, well now that nephew is on mind-numbing drugs to keep him quiet and compliant.

Instead of castrating him to control his behavior, imagine the benefits if he had been allowed to reproduce. We have an animal who is a genius of his kind. What else might we have learned from him or his descendants?

Congolese chimps modify fishing-sticks to make them even more effective tools

edyong — Tue, 03 Mar 2009 18:00:00 +0000

Congolese chimps modify fishing-sticks to make them even more effective tools

In the Goualougo Triangle of the Republic of Congo, a chimpanzee is hungry for termites. Its prey lives within fortress-like nests, but the chimp knows how to infiltrate these. It plucks the stem from a nearby arrowroot plant and clips any leaves away with its teeth, leaving behind a trimmed, flexible stick that it uses to "fish" for termites.

Many chimps throughout Africa have learned to build these fishing-sticks. They insert them into termite nests as bait, and pull out any soldier termites that bite onto it. But the Goualougo chimps do something special. They deliberately fray the ends of their fishing sticks by running them through their teeth or pulling away separate fibres - just watch the chimp on the right in the video below.

The result is a stick with a brush-like tip, which is far more effective at gathering termites than the standard model. This population of chimps has modified the typical design of the fishing stick to turn it into a better tool. They truly are intelligent designers.

Naturalists first suggested that chimps deliberately manufacture brush-tipped sticks to dig for termites in 1985 and indeed, these sticks have been found all over central Africa. But fishing sticks fray naturally when they're used and East African chimps are known to actively remove the frayed ends from their probes. So it seems that in most cases, the brush-sticks are just the discarded remnants of active tools.

Crickette Sanz from the Max Planck Institute for Evolutionary Anthropology has found the first true evidence that some chimps actually shape them that way. She used motion-sensing cameras to record chimps fishing at termite nests and collected footage of 31 individuals, 54 fishing attempts and 65 hours of foraging. Her videos clearly show that the chimps deliberately fashion their fishing-sticks with distinctive brush-tips.

All of the chimps arrived at the termite nests with arrowroot stems and proceeded to refine their tools. The vast majority of the modifications involved fraying the tips, mostly by pulling the ends through their teeth, or by biting individual fibres apart. That behaviour has never been seen in other contexts - it's an action specific to the creation of fishing-sticks.

After fashioning the brush, they would almost always straighten it by pulling it through their partially closed fist, presumably to allow them to insert it more easily into a nest-hole. Occasionally, the videos showed that the stick wouldn't fit, whereupon the chimp would straighten it again until it did.

The brush-tipped sticks are multi-purpose tools too. Sanz's video showed that four chimps occasionally flipped the stick around and used the blunt end to clear debris from a nest-hole, before using the brush again to collect termites.

To Sanz, these shots were clear signs that the chimps were deliberately modifying their tools in a way that other populations were not. To make sure that she wasn't just laying her own interpretations on the footage, she asked a research assistant who had no idea what the study was about to analyse the videos. They came to the same conclusion.

Sanz also found that the brush-tipped design is an improvement over the standard model. She gave standard and brush-tipped sticks to five local guides and set them out to fish for termites. Each guide tried both versions on the same holes, for the same amount of time and the same number of attempts.

The standard models fared relatively poorly, picking up termites 18% of the time and averaging just one insect every four attempts. The brush-tipped tools were dramatically more successfully - they gathered termites on 76% of fishing attempts and netted about 5 insects per go, almost 20 times as many as the unmodified tools.

The results clearly show that this particular group of chimps have improved on the standard blueprint of fishing-sticks and they craft these tools with specific design in mind. Surely not long then before they design a stick with a corkscrew, nail file and small pair of tweezers in it too...

Reference: Biology Letters doi:10.1098/rsbl.2008.0786

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edyong Tue, 03/03/2009 - 13:00

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