In the previous post we saw that vampire bats were more diverse and more widespread during the Pleistocene than are they today. Two things stand out (to me) as being particularly interesting; firstly, that some of these vampires seem to have differed in morphology, and therefore presumably in ecology and behaviour, from the living vampire species; and secondly, that some of these vampires survived until very, very recently. Here, we look at these two areas in more detail...
What species were these fossil vampires feeding from? Of the three living vampires, both the Hairy-legged vampire Diphylla ecaudata and White-winged vampire Diaemus youngi mostly prey on birds. However, the Common vampire Desmodus rotundus mostly preys on mammals, and because the fossil species are members of the genus Desmodus, it is reasonable to assume that they, also, mostly fed on mammals. A few vampire bat fossils are preserved associated with large mammals. A fossil Common vampire from a Brazilian cave, radiometrically dated to about 12,000 years ago, was discovered adhering to the underside of a coprolite produced by the sloth Nothrotherium (Czaplewski & Cartell 1998) and D. stocki fossils from Florida are preserved in the same caves as ground sloths. A skull belonging to the giant vampire D. draculae was preserved in association with a skull of the extinct horse Equus neogeus. None of these associations demonstrate the predatory preference of the vampire species concerned, but they are at the very least highly suggestive. The idea that some of these bats may have fed on giant sloths is likely and entirely acceptable, and one published life restoration - a drawing by Randy Babb, in Brown (1994) - depicts a D. stocki feeding on a nothrotheriid sloth.
Intriguingly, the morphology of some of these vampires suggests that they differed in ecology and behaviour from the living vampire species. Both D. archaeodaptes and the Cuban species D. puntajudensis seems to have had far more freedom of movement in their jaw joint that the Common vampire, a feature suggesting that they somehow differed in how they procured and/or bit their prey (Morgan 1991, Suarez 2005). The robust hindlimb bones of D. puntajudensis and D. stocki also suggest that their style of terrestrial locomotion differed from that of the Common vampire, though exactly how it differed remains unknown. The large size of D. stocki, D. draculae and the Argentinean giant form of course indicate that they fed on larger prey than living vampires and, as noted, these fossil bats are sometimes found associated with ground sloths. In the adjacent illustration I've shown D. stocki feeding from the leg of a teratorn. I knocked the drawing up myself because I'm bored with using pictures of living vampires.
Many fossil vampire records occur outside of the 10 degree C minimum isotherm that, today, marks the distributional limit for vampire bats. Rather than these records indicating cold-tolerance among the extinct species, it is more likely that the respective regions were warmer in the past than they are now, and indeed the associated fauna and other data shows that this was the case. Even so however, some of these records - such as occurrences of D. stocki in Florida - show that these bats inhabited warm temperate climates, and were not only restricted to tropical conditions. Some of the extinct vampires may also have been less reliant on the extremely high humidity that is required by living vampires, as some of the caves where their remains are found don't appear to have been especially humid.
Also of particular interest is the fact that some of these vampires survived until very, very recently. D. puntajudensis survived into the Holocene, and D. stocki even survived into historical times and was still alive 3000 years ago on San Miguel Island off southern California (Ray et al. 1988). Most remarkable of all is D. draculae. The original Venezuelan discoveries of this species might be as young as 10,000 years old and were discovered associated with the bones of extant species. Even better, the large D. draculae-like vampire from Argentina has been dated to an unbelievable 300 years ago (Pardinas & Tonni 2000), so this unnamed species was alive in c. 1700. The dates are so incredibly recent that several mammalogists have noted the possibility that D. draculae and similar forms might still survive, and await discovery (Ray et al. 1988, Trajano & de Vivo 1991). Indeed Trajano & de Vivo (1991) noted rumours from local people about particularly large Brazilian vampires that sometimes attacked their horses and cattle [adjacent pics of leaping vampire from here, as is the picture of the Camazotz statue at the top].
Various myths, legends and stories from Mexico and Central America describe large bats that, some researchers suggest, might be further references to these big vampires. The best known of these is Camazotz (also sometimes spelt Camalzotz), a bat-headed monster who (in some Mayan tales) inhabited the cave Zotzilaha in what is now Guatemala. Camazotz apparently translates as 'death bat' or 'snatch bat', and Gable (1997) noted that stories of bat-like demons also persisted in the cultures of Chiapas in Mexico and elsewhere. While Camazotz has conventionally been associated with the Common vampire, it is conceivable that big species like D. draculae were the inspiration for these tales. The Brazilian Muras Indians have tales of an enormous blood-eating bat called Caoera that is as large as a vulture, and again it is tempting to think that this just might be an exaggerated reference to a genuine giant vampire.
Also of interest are the various modern tales that tell of how people in Argentina and elsewhere have been attacked by immense vampire bats (go here to see examples). It is doubtful if these stories really have any truth in them: if they do then the bats they report are considerably larger even than D. draculae, and differ significantly from real vampires in not attacking stealthily.
And that will do for now. There is still one major area concerning vampires that I have yet to address, and this is how blood-feeding actually evolved within the group. This, and much more, due to come soon...
Refs - -
Brown, D. E. 1994. Vampiro: the Vampire Bat in Fact and Fantasy. High-Lonesome Books (Silver City, New Mexico).
Czaplewski, N. J. & Cartelle, C. 1998. Pleistocene bats from cave deposits in Bahia, Brazil. Journal of Mammalogy 79, 784-803.
Gable, A. 1997. Two possible cryptids from Precolumbian Mesoamerica. The Cryptozoology Review 2 (1), 17-25.
Morgan, G. S. 1991. Neotropical Chiroptera from the Pliocene and Pleistocene of Florida. Bulletin of the American Museum of Natural History 206, 176-213.
Pardinas, U. F. J. & Tonni, E. P. 2000. A giant vampire (Mammalia, Chiroptera) in the Late Holocene from the Argentinean pampas: paleoenvironmental significance. Palaeogeography, Palaeoclimatology, Palaeoecology 160, 213-221.
Ray, C. E., Linares, O. J. & Morgan, G. S. 1988. Palaeontology. In Greenhall, A. M. & Schmidt, U. (eds) Natural History of Vampire Bats. CRC Press (Boca Raton, Florida), pp. 19-30.
Suarez, W. 2005. Taxonomic status of the Cuban vampire bat (Chiroptera: Phyllostomidae: Desmodontinae: Desmodus). Caribbean Journal of Science 41, 761-767.
Trajano, E. & de Vivo, M. 1991. Desmodus draculae Morgan, Linares, and Ray, 1988, reported for southeastern Brasil, with paleoecological comments (Phyllostomidae, Desmodontinae). Mammalia 55, 456-460.
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No chance of C-14 contamination or anything in that 300-year date...?
All that talk regarding giant vampire bats at the link, recalls to mind the Chupacabra mythos. I'm surprised you didn't go there Darren, with your facination for all things cryptozoological.
Given that modern day teratorn relatives storks and new world vultures defacate down their legs as a means of temperature regulation, I'm not sure I'd want to be the vampire in your picture.
Good call, Cristopher.
Actually, it got me wondering if vampire bats, wherever they're found, spawn some sort of similar archetype. After all, blood-feeing is inherently mystical (or taboo) in many cultures. The idea of draining power, or life, or the soul, from a victim seems a logical step.
Yaaaarrrggghh!
Excellent work as always, Darren! I can't wait for more kaiju-biology (I learned a new word, and I hope I used it correctly).
Thanks to all for their comments. I deliberately avoided discussing Chupacabras, mostly because I think its got nothing whatsoever to do with vampire bats (and probably nothing to do with zoology either, despite the efforts of some to explain it as an arboreal porcupine, giant spiny rat, amphibious primate or new type of xenarthran... ).
On teratorns and the possibility of urohydrosis: good call R. Arthur Wilderson. It's possible that teratorns did this too, but we don't know if they did: the main reason for my uncertainty is that teratorn affinities are still undecided, though if they really are allied to New World vultures then it becomes more likely that they did practise this behaviour after all. Incidentally the formerly popular idea about storks and New World vultures being close kin has now fallen by the wayside.. the fact that storks also practise urohydrosis is better explained as a convergence.
Anyway, even if teratorns did do this, they wouldn't have done it during the night while sleeping, so the bat in my drawing is safe.
This isn't precisely relevant to vampire bats, but I wanted to let Darren know how very much I am enjoying his blog since I discovered it a few weeks ago. Sometimes I have to look up every word except for the prepositions and conjunctions, but ah well. The science is fascinating.
I would like to ask about primate or hominid biology. My "thing" is fiber--yarn or string if you will and I have long suspected that string is possibly as old as any stone tool. I suspect the reason for this is the peculiarity of the human evolutionary line--and it's the one thing that NO ONE ever seems to discuss.
What critter other than womankind and her foremothers bleeds every month. I've looked all over and can't seem to find any information on menstrual cycles in other primates (don't seem to be any even in bonobo apes which are sexually active all the time) or in our hominid forebears. Technology follows need and it would seem to me that dribbling blood around as a billboard for predators would provide a huge push to develop techniques for protecting menstruating females and some means of dealing with the blood itself.
Any thoughts
Llinn
Well, El Chupacabra...This thing is really a very good example how mass hysteria, superstition and ordinairy critters materialized in some kind of supernatural blood-sucking monster. The fact alone that there are uncountable completely contradictory descriptions if it shows alone that most "sightings" were only invented or shameless exagerated. Perhaps the fact that vampire bats are really part of the south american fauna, added some additional believe in the existence of such a beast, but I also doubt that it was the key factor. Some people claim that ancient south american rock carvings of blood-sucking creatures (which are in this cases no bats) show the chupacabra, ignoring the fact that in some of this cultures the ritual consumption (in some cases the own) blood was common. But so many of the mythical creatures which owns the prominent jaguar teeth which were added to many different beings in south american art, are seen as some kind of chupacabra.
The deeds which are said to be commited by the chupa are in most cases not more than those of poaching dogs and other natural predators, but the superstitious peasants (and many other people) are more willing to believe in a monster which sucked to blood out of their livestock. An aquaintance of me has several chickes, and last year he was haunted by a mysterious beast which killed many of his chickens, ripping their throat of and drinking their blood. But this was nothing more than a normal marten (what he knew of course), but in Mexico the same situation could easily result in a local chupacabra-hysteria.
Do you remember the famous "chupacabras" which were encountered some time ago in the US? They were nothing more than many dogs, coyotes and foxes, but many people thought they were real chupacabras. The problem is that many medias are not willed to explain things, but to make things mysterious, and monsters are a good topic to make an interesting story. You have surely read about the "alien" which was catched some days ago by russian fishers. Many people actually think that this ordinairy skate is extraterrestrial, and the medias keep the myth alive. Today I read the story once again at the homepage of the biggest german newspaper (this one is nearly as bad as the english "Sun" and I had the link only from a forum) and they wrote even more bullshit than the normal para-sites. You know the stuff, mysterious being, probably extraterrestrial, scientists are not able to identify it...arrggghhh.
It really hurts that newspapers like this add every day their part to the public stultification.
Answers.com's article on Cercopithecines (Old-World monkeys and apes) says all have a menstrual cycle (where the uterine lining is shed). Wikipedia says this only occurs in apes. (The cycle lasts 29 days in Orngs, and 37 days in chimps). Neither source references these statements. A google search for "Menstruation non-human primates" produces a lot of studies avaliable on pubmed or JSTOR, so I know which I'd believe. (Sadly these articles aren't always publically accessible, but you can often get the abstracts).
Humans are unusual among apes in that their fertile period is not advertised (Concealed Ovulation). It occurs in some monkey species (Vervets are probably the best studied).
A google search for "Menstruation non-human primates" comes up with a lot of research.
Bloodsuckers rock.
It's fascinating that among tetrapods, haematophagy seems to have evolved only in bats and perhaps 2 lineages of passerine birds. I do wonder why it's not more prevalent.
And cathartids may not be close relatives of the storks? Then where do they belong? Back with the accipitrids? (Read somewhere that accipitrids and falconids may not be that closely related after all). And I recall that though older studies seemed to group owls with nightjars and kin, it appears that owls may be close relatives of diurnal raptors instead.
Bird systematics: ACK.
I just want to comment on the wonders of scientific nomenclature. Its pretty impressive having a special word for "cooling yourself by peeing down your legs".
It's almost as good as something invented by Terry Pratchett.
Probably all placentals. I've once read that rats have a menstruation cycle that lasts 11 days. The source (which I've forgotten) mentioned this to counter claims that the human cycle is somehow coupled to the moon.
Interesting that it takes longer in chimps. I'd have guessed it was correlated with body size... apparently not...
The latest major morphological study of modern bird phylogeny (Livezey & Zusi, 2007) places cathartids together with the other diurnal birds of prey, to which owls are a sister group; the most recent major molecular study (Ericson et al., 2006) places both cathartids and owls in what might be called the 'higher land-bird assemblage' in positions that do not allow for a close relationship to falconids, but don't exclude the possibility of a relationship to accipitrids (the three clades are in a polytomy that also includes other clades). In both cases, a position for cathartids in the 'higher land-birds' is far removed from storks in the 'higher water-bird' assemblage. Neither study places nightjars near owls, but they differ significantly (very, VERY significantly) on where nightjars do go.
Looking forward to hearing about the rhinogradentians :-)