Tetrapod Zoology

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ResearchBlogging.org

I hope everyone has been enjoying my write-ups of Inside Nature’s Giants (ING), series 2 (for comments on episode 1 go here, and for thoughts on episode 2 go here). Time to look at ep 3: the big cat one.

Given that big cats are more popular (among the general populace) than are either sharks or snakes, it’s predictable that this was the most discussed, most anticipated episode. Like the others, it was excellent [adjacent image © Windfall Films/Channel 4].

And let me say again how good the whole of ING series 2 was: well done to everyone involved, you left us wanting more. And to those who haven’t seen the series (yet), I hope these articles serve as useful promotional tools – it’s certainly not my intention to steal proverbial thunder. WARNING: total, epic spoiler ahead…

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So, to work. Episode 3 featured dissections of both a Lion Panthera leo and Tiger P. tigris* [Panthera taxa shown above (from wikipedia)... but no Snow leopard**]. Mark Evans noted at the start that one of the aims was to see whether lions and tigers are essentially the same under their skins, or whether any differences would become apparent. Most of the filming was done at the Royal Veterinary College: Tecumseh Fitch, a cognitive biologist who you might know best for his publications on mammalian vocal tracts, worked on the dissections with Joy Reidenberg and Andrew Kitchener. Penny Hudson, who works on cheetah locomotion at the RVC, also appeared. Members of the team travelled to Africa to see lions in the wild, while Richard Dawkins discussed the general principles behind predator/prey ‘arms races’.

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* Obligatory mention here of the fact that some workers regard P. tigris of tradition as consisting of three phylogenetic species. Under this proposal, the Sumatran tiger P. sumatrae and Javan tiger P. sondaica warrant separation (Cracraft et al. 1998, Mazák & Groves 2006).

** Molecular data indicates firm inclusion of the Snow leopard within Panthera. However, because it differs in throat anatomy, skull shape, tooth shape and limb proportions from definite Panthera species (in some respects it’s rather cheetah-like), some anatomists argue that the Snow leopard warrants placement outside of Panthera and still use the name Uncia uncia for the species [adjacent Snow leopard photo by Bernard Landgraf, from wikipedia].

I know that some viewers were a little disappointed to see that the matter of how lions and tigers can be differentiated wasn’t really elucidated. But perhaps that’s because the two are extremely similar, and it’s this similarity that was concentrated on, rather than the differences. The fact that lions and tigers can produce hybrids was looked at (but this doesn’t mean much about lions and tigers specifically, given that hybrids between just about any and all similar-sized cats are possible and have been produced in captivity) [lion skeleton below, courtesy Windfall Films. Photographed at the University Museum of Zoology, Cambridge, I think].

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Indeed, something that couldn’t be covered in the episode is that, yes, lions and tigers are similar, but they’re not especially similar among the big cats; rather, all the big cats (indeed, all cats) are highly similar, and I would say that people only think of lions and tigers as being similar because both are similar in size. Most studies show that tigers and lions aren’t even that close within Panthera: lions are part of a ‘spotted clade’ that also includes leopards and jaguars, while tigers lie elsewhere, possibly being the sister-taxon to the Snow leopard (Bininda-Emonds et al. 2001, Burger et al. 2004, Yu & Zhang 2005, Johnson et al. 2006).

The possible function of the lion’s mane was looked at. As has been discussed on Tet Zoo before [see book cover below], there are several competing hypotheses that hope to explain mane evolution: these explanations may well be overlapping and compatible, and it may also be that different factors take precedence in different parts of the lion’s range. So, while the mane is conventionally regarded as a visual signal of maturity and fitness in some lion populations (Yamaguchi et al. 2004), its development seems to be delayed in some populations (Kays & Patterson 2002) because having a large mane interferes with thermoregulation (Gnoske et al. 2006, Patterson et al. 2006).

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Something of incidental interest is the observation that zoo lions typically have larger manes than wild ones (Patterson et al. 2006, pp. 196-197), presumably because their nutrition is better and their manes are subjected to less abrasion than that experienced by wild lions (hmmm… does this explain why there are so many claims of Barbary lions being ‘discovered’ in captivity?). Captive lion cubs are sometimes larger than their wild counterparts, and one study reported that captive tigers have deeper occipital regions than wild animals (Duckler 1998), apparently because captive animals engage in excessive grooming and thereby over-exercise their head and neck musculature. O’Regan (2001) found that the skulls of captive big cats were broader across the zygomatic arches than wild animals, but it wasn’t clear why this was so. Anyway, I digress.

Laryngeal anatomy: why lions are like people

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I’m a big fan of laryngeal and tracheal anatomy, and one of the main stories focused on in this episode concerned the structure and function of the big cat larynx and its role in vocalising. Well known (and oft-mentioned) is that big cats differ from little ones in having a ligamentous (rather than ossified) epihyoideum component in the throat skeleton, thereby allowing them to roar (though it is not this component alone that allows roaring (see Hast 1989); as usual, things have turned out to be more complicated). Less well known is that the big cat larynx is positioned well posterior in the throat. Weissengruber et al. (2002) inferred the thyroid cartilage (the largest component of the larynx: the part often called the ‘Adam’s apple’) to be about level with the axis vertebra in Panthera (in contrast, it’s only just behind the rear margin of the lower jaw in a domestic cat and most other ‘ordinary’ mammals). However, they suggested that, in life, its normal resting position was much lower (as in, level with the 5th-7th cervical vertebra) (see Pérez et al. (2006) for data on tigers) [adjacent picture shows (l ro r) Penny Hudson, Mark Evans and Tecumseh Fitch dissecting the lion's throat. Image © Windfall Films/Channel 4].

In having such a low-set larynx, Panthera cats resemble us humans, a point made during the episode. Big cats also resemble humans in that the larynx is bigger in males than in females, and it migrates posteriorly as an animal approaches sexual maturity. Worth noting here is that a descended larynx is not unique to big cats and humans*: some deer also have a permanently descended larynx, and koalas, some bats and possibly elephants have one too (Fitch & Reby 2001, Weissengruber et al . 2002, McElligott et al. 2006). I’ve mentioned some of this before when discussing Fallow deer Dama dama (and this reminds me, there’s a near-finished article on the subject of mammal throats and vocalisation waiting in the wings) [lion palate and teeth shown below, image © Windfall Films/Channel 4].

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* Seriously, humans are nice and everything, but they’re not all that special. All those old claims about humans being “the only animals capable of [insert behavioural or cognitive trait]“, or “the only animals possessing [insert anatomical component or configuration]” stem from lack of knowledge or data on non-humans.

During the dissection, it was discovered that the lion’s sternohyoid – one of the muscles involved in pulling the larynx down toward the chest during vocalising – attached deeper in the chest than previously thought. This means that the larynx can actually be pulled even further ventrally than hypothesised, hence helping to explain how lions can produce such low fundamental frequencies and low formant frequencies in their roars. The deep-set larynx, combined with the length of the pharynx, very large, fleshy vocal folds and cavernous mouth, has led some workers to propose that the big cat mouth and throat functions in analogous fashion to a brass trumpet (Hast 1989). Even in death, bodies can be made to vocalise: all you have to do is force air from the lungs out through the larynx. In series 1, a dead Nile crocodile was made to vocalise when its trachea was connected to a hose, and the same neat trick was used here on the lion. Nice!

Claws, paws and jaws

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The forelimb anatomy of big cats got some coverage. Cat wrists and hands are more flexible that those of carnivorans – like hyaenids and dogs – that don’t use their hands in grappling with prey. We were shown how cat claws only become unsheathed when both the dorsal and ventral tendons on the digits are flexed (the extensor digitorum lateralis and communis tendons dorsally, and the flexor digitorum profundus tendons ventrally). Cat claws are hyper-retracted when not in use, and are actually ‘stored’ in special concavities located on the lateral sides of the penultimate phalanges. Accordingly, those phalanges are strongly asymmetrical. The fore- and hindlimb claws of cats are different in shape and function, with the strongly hooked manual claws acting in prehension and combat, and the more blade-like pedal claws acting in raking (Bryant et al. 1996). Note to dinosaur fans: dromaeosaur pedal digit II claws look similar to cat pedal claws, and this is why I think that a raking/disembowelment role for these claws remains viable (and, in part, why the climbing crampon idea is not). Someone should look into this properly, hint hint [adjacent image: Panthera ligaments involved in claw retraction being manipulated. Image © Windfall Films/Channel 4].

Incidentally, the claw retraction mechanism present in cats isn’t as unique as tradition would have it: Nandinia (the African palm civet) and various viverrids have the same mechanism, and a less elaborate but very similar system is present in some mustelids and procyonids. In fact, retractile claws might be a synapomorphy for the whole of Carnivora (since lost or reduced in many lineages).

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ING also covered biting styles and the function of the teeth, and they included a bit of comparison between Panthera and Smilodon [replica skull shown here © Windfall Films]. However, I don’t think that what was said was really up-to-date in terms of current ideas on sabretooth behaviour. Recent studies on the predatory behaviour of these cats indicate that they practised a conventional felid throat bite (aiming for the windpipe and blood vessels) after restraining the prey with massive forelimb and pectoral musculature (Antón & Galobart 1999, Antón et al. 2004).

Final thoughts!

So there we have it. ING ep 3 was great, but (in my opinion), the White shark and giant python articles were better. But that sounds a bit unfair, as all the episodes of series 2 were great. In no way did this second series seem at all ‘samey’ or tired in view of series 1; each episode focused on entirely novel material of the sort not really shown on TV before [image below © Windfall Films/Channel 4].

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And the episodes were pretty comprehensive: it occurred to me as I wrote up the python episode that it had covered pretty much everything you would want to touch on when providing an introductory overview to snake anatomy and biology. I also think that the episodes did a good job of finding the right balance in terms of showing both ‘sciencey’ bits (the dissections and discussions of anatomy), and more standard natural history-themed bits. There was more than enough to keep a hard-core nerd interested yet, at the same time, many people with only a passing interest in science, natural history or animals also remained transfixed. The people involved in the series represent a good mix. All came across well: as likeable, knowledgeable and never as arrogant. At the risk of pissing off some of my friends in TV-land, I have to say that at least a few of the people who feature on science-based TV programmes come across as extremely annoying, or extremely arrogant, or both, so it’s nice to walk away from a TV series without a feeling of rage or frustration. So, I am totally happy with ING series 2, I loved it.

As mentioned earlier, a special episode of ING, focusing on giant squid, will be featured some time later this year. I also hear inklings that work on series 3 is underway – I really hope so, and I hope that ING becomes a regular thing on our TV sets. Well done to Windfall Films, to Channel 4, and to everyone involved. You served us well, showed us so much, and did not let us down.

Special thanks to Zach Buchan for his help with this series of articles, to Joy Reidenberg, Penny Hudson, and to Tom Mustill at Windfall Films. If you’re on facebook be sure to ‘like’ Joy’s page.

For other Tet Zoo articles on ING, see…

For previous Tet Zoo articles on cats see…

And, if you liked the discussion above of laryngeal anatomy and what it might mean for vocalisation, be sure to check out…

Refs – -

Antón, M. & Galobart, À. 1999. Neck function and predatory behavior in the scimitar toothed cat Homotherium latidens (Owen). Journal of Vertebrate Paleontology 19, 771-784.

- ., Salesa, M. J., Pastor, J. F., Sánchez, I. M., Fraile, S. & Morales, J. 2004. Implications for the mastoid anatomy of larger extant felids for the evolution and predatory behaviour of sabretoothed cats (Mammalia, Carnivora, Felidae). Zoological Journal of the Linnean Society 140, 207-221.

Bininda-Emonds, O. R. P., Decker-Flum, D. M. & Gittleman, J. L. 2001. The utility of chemical signals as phylogenetic characters: an example from the Felidae. Biological Journal of the Linnean Society 72, 1-15.

Bryant, H. N., Russell, A. P., Laroiya, R. & Powell, G. L. 1996. Claw retraction and protraction in the Carnivora: skeletal microvariation in the phalanges of the Felidae. Journal of Morphology 229, 289-308.

Burger, J., Rosendahl, W., Loreille, O., Hemmer, H., Eriksson, T., Götherstrom, A., Hiller, J., Collins, M. J., Wess, T. & Alt, K. W. 2004. Molecular phylogeny of the extinct cave lion Panthera leo spelaea. Molecular Phylogenetics and Evolution 30, 841-849.

Cracraft, J., Feinstein, J., Vaughn, J. & Helm-Bychowski, K. 1998. Sorting out tigers (Panthera tigris): mitochondrial sequences, nuclear inserts, systematics and conservation genetics. Animal Conservation 1, 139-150.

Duckler, G. L. 1998. An unusual osteological formation in the posterior skulls of captive tigers (Panthera tigris). Zoo Biology 17, 135-142.

Fitch, W. T. & Reby, D. 2001. The descended larynx is not uniquely human. Proceedings of the Royal Society of London B 268, 1669-1675.

Gnoske, T. P., Celesia, G. G. & Kerbis Peterhans, J. C. 2006. Dissociation between mane development and sexual maturity in lions (Panthera leo): solution to the Tsavo riddle? Journal of Zoology 270, 551-560.

Hast MH (1989). The larynx of roaring and non-roaring cats. Journal of anatomy, 163, 117-21 PMID: 2606766

Johnson, W. E., Eizirik, E., Pecon-Slattery, J., Murphy, W. J., Antunes, A., Teeling, E. & O’Brien, S. J. 2006. The Late Miocene radiation of modern Felidae: a genetic assessment. Science 311, 73-77.

Kays, R. W. & Patterson, B. D. 2002. Mane variation in African lions and its social correlates. Canadian Journal of Zoology 80, 471-478.

Mazák, J. H. & Groves, C. P. 2006. A taxonomic revision of the tigers (Panthera tigris) of southeast Asia. Mammalian Biology 71, 268-287.

McElligott, A. G., Birrer, M. & Vannoni, E. 2006. Retraction of the mobile descended larynx during groaning enables fallow bucks (Dama dama) to lower their formant frequencies. Journal of Zoology 270, 340-345.

O’Regan, H. J. 2001. Morphological effects of captivity in big cat skulls. In Proceedings of the 3rd Annual Symposium on Zoo Research. North of England Zoological Society, Chester Zoo, pp. 18-22.

Patterson, B. D., Kays, R. W., Kasiki, S. M. & Sebestyen, V. M. 2006. Developmental effects of climate on the lion’s mane (Panthera leo). Journal of Mammalogy 87, 193-200.

Pérez, W., Lima, M. & Cunarro, B. 2006. Larynx anatomy in a Tiger (Panthera tigris, Linnaeus, 1758). Journal of Animal and Veterinary Advances 5, 1093-1095.

Weissengruber, G. E., Forstenpointner, G., Peters, G., Kübber-Heiss, A. & Fitch, W. T. 2002. Hyoid apparatus and pharynx in the lion (Panthera leo), jaguar (Panthera onca), tiger (Panthera tigris), cheetah (Acinonyx jubatus) and domestic cat (Felis silvestris f. catus). Journal of Anatomy 201, 195-209.

Yamaguchi, N., Cooper, A., Werdelin, L. & Macdonald, D. W. 2004. Evolution of the mane and group-living in the lion (Panthera leo): a review. Journal of Zoology 263, 329-342.

Yu, L. & Zhang, Y.-p. 2005. Phylogenetic studies of pantherine cats (Felidae) based on multiple genes, with novel application of nuclear β-fibrinogen intron 7 to carnivores. Molecular Phylogenetic and Evolution 35, 483-495.

Comments

  1. #1 Michael P. Taylor
    September 6, 2010

    Indeed, every single time I’ve sat down to watch Inside Nature’s Giants it’s been with a feeling of amazement and gratitude that something so uncompromisingly factual is allowed space in the TV scheduled. To Darren’s well-merited thanks to the production crew, I’d like to add my own thanks to whoever it is at Channel 4 that’s managed to get two series, and maybe a third, on the air. It really does go some way to restoring my faith in TV as an educational medium.

    And if Joy R. is reading this, and has any influence over Series 3 critters: please, please — ostrich! Or some kind of ratite, anyway. Failing that, a large raptor. The absence of birds has been the one downside of ING so far. A giant tortoise would also be awesome.

  2. #2 Anonymous
    September 6, 2010

    “Indeed, something that couldn’t be covered in the episode is that, yes, lions and tigers are similar, but they’re not especially similar among the big cats; rather, all the big cats (indeed, all cats) are highly similar, and I would say that people only think of lions and tigers as being similar because both are similar in size.”

    I wonder why that is. I mean, other hypercarnivorous lineages throughout history, like dromaeosaurids, for example, vary somewhat in their overall morphology. I’ve heard its due to the fact that in cats straying too far from the basic felid bodyplan tends to have dire consequences for the species due to the way cats are specialized, but I don’t know why it is so strict for cats.

    “Something of incidental interest is the observation that zoo lions typically have larger manes than wild ones (Patterson et al. 2006, pp. 196-197), presumably because their nutrition is better and their manes are subjected to less abrasion than that experienced by wild lions (hmmm… does this explain why there are so many claims of Barbary lions being ‘discovered’ in captivity?).”

    I wonder if this applies to other vertebrate groups where large display devices are a sign of individual health. Do elks and other cervids tend to grow bigger antlers in captivity? Do peacocks grow more vibrant tails?

    “Even in death, bodies can be made to vocalise: all you have to do is force air from the lungs out through the larynx. In series 1, a dead Nile crocodile was made to vocalise when its trachea was connected to a hose, and the same neat trick was used here on the lion. Nice!”

    I wonder if this means that we could do the same trick to try and figure out an aproximate vocalization for extinct taxa (i.e. non avian dinosaurs and various mammals groups that are no longer with us). Obviously the sound produced won’t be the ‘exact’ sound that the animal would make, and we’d probably have to work with groups where the throat or soft tissue of the throat anatomy is preserved, but it would still be interesting to see if those ‘remixed animal roars’ used for many dinosaurs in movies are really within the range of what they may have sounded like.

  3. #3 Stu of the Peak
    September 6, 2010

    Thanks for these reviews Darren. I set my SkyBox when I went off digging in the Hell Creek but when I got back gremlins had been at work* and the remaining episodes hadn’t recorded so I’m glad to have the chance to catch up.

    *Operator error?

  4. #4 Darren Naish
    September 6, 2010

    Anonymous: on comparing dromaeosaurs with big cats, the big cats you’re thinking of represent a (more or less) ‘complete roster’ of species from one little chunk of time. By comparison, the dromaeosaurs you’re thinking of likely represent only a small sample of actual diversity, spread over many millions of years. Perhaps this makes it look as if all dromaeosaurs are highly distinct, whereas – were you actually alive and observing species in the Albian or whatever – you’d end up seeing lots of highly similar species. Of course, how reliable a mirror the fossil record is in reflecting actual biological diversity remains hotly contested. I think it’s unlikely that dinosaurs were as low in diversity as some palaeontologists imply.

  5. #5 chris y
    September 6, 2010

    n having such a low-set larynx, Panthera cats resemble us humans, a point made during the episode. Big cats also resemble humans in that the larynx is bigger in males than in females, and it migrates posteriorly as an animal approaches sexual maturity.

    So if a lion could talk, maybe we would understand it.

  6. #6 Darren Naish
    September 6, 2010

    Ha :) Cue Hoover the seal… (my article on Hoover has been sat in limbo for some years now, must get it finished).

  7. #7 shiva
    September 6, 2010

    I read somewhere that the reason Barbary (and Cape) lions have/had longer/thicker manes than other lions was not genetics, but climate – living at the northern (and southern) extremities of the lion’s range, ie where there are distinguishable winters, results in heavier hair growth. Thus captive lions (from equatorial African subspecies) born in zoos in Europe and North America also have heavier manes than lions of the same subspecies born in Africa, and the length and thickness of the mane is not a reliable indicator of subspecies in lions (although things like the colour and the extent of skin covered by it, i suppose, might be).

  8. #8 Jerzy
    September 6, 2010

    “the more blade-like pedal claws acting in raking and disembowelment (Bryant et al. 1996)”

    !!!??? Find me one picture of a lion or tiger disembowelling anything with its hindclaws.

    Crampons for support, yes.

  9. #9 Jerzy
    September 6, 2010

    Skulls of lions in captivity are indeed different, probably from the diet (less rough food, less developed musculature and bones). Larger manes are due to less abrasion and of course, selection towards impressive display animals over many generations.

    Indeed, some zoo people talk about “cage lion” or a different phenotype developed in zoos – with attributes such as slightly shorter legs, shorter tail, larger mane etc.

    This greatly complicates the matter of “Barbary lions” or “Cape lions” in zoos. And specimens of extinct Barbary and Cape lions are few, often in hard-to-reach museums, and often poorly preserved or dubiously labelled.

    On top of that, variation in wild lions is not at all well known. Lions in eg. West Africa, Sahel or Ethiopia are almost unstudied. Pretty ironic, but countless studies and pictures of lions come from the same few national parks in East and South Africa, often from the same prides.

  10. #10 Allen Hazen
    September 6, 2010

    Probably this just shows how ignorant I am, but the lion skeleton (photo above) looked surprisingly gracile: if you’d just shown me the photo and asked me to identify the species, I might have gone for something like cougar.
    (Maybe my problem is that the big cat skeletons I have gazed upon longest were Smilodon: hyper-robust by the standards of our dainty modern felids.)

  11. #11 Joy Reidenberg
    September 6, 2010

    Dear Michael Taylor:
    Keep watching, and your wish may be answered! There are plans to do a large bird, but this may depend upon funding, which in turn depends upon viewership. So, get all your friends to tune in! Also, although a tortoise might be fun, how about a sea turtle? Stay tuned…!

  12. #12 Joy Reidenberg
    September 6, 2010

    Dear Chris Y:
    Regarding the lion’s larynx, it is interesting that it is set so low in the neck. This really surprised me, but made sense because it allows a larger resonating space above the sound source for modifying sounds (roars) – just as the longer tube-work in a trombone does in the extended position. However, the dissimilarity with humans lies in the fact that, at rest, the larynx is still interlocked with the soft palate (epiglottis overlapping soft palate). In this interlocked position, it maintains the classic two-pathway pattern typical of all mammals except adult humans. Breathing and swallowing are separated in lions, which protects the airway from food incursions during swallowing. Humans, however, have lost this protection due to the descended laryngeal position in conjunction with the loss of the soft palate – epiglottic overlap. Humans did not extend the soft palate to accompany the descent of the larynx. This, along with changes in tongue shape/position, may have enabled more vowel sound production – which makes human speech unique. For more info, check out articles written by J. Laitman or P. Lieberman on the evolution of human laryngeal position.

  13. #13 Lionel L.
    September 7, 2010

    Keep up the great work! Looking forward to a pinniped dissection; a southern elephant seal would be fantastic!

  14. #14 David Marjanović
    September 7, 2010

    Obligatory mention here of the fact that some workers regard P. tigris of tradition as consisting of three phylogenetic species. Under this proposal, the Sumatran tiger P. sumatrae and Javan tiger P. sondaica warrant separation (Cracraft et al. 1998, Mazák & Groves 2006).

    And now that the Caspian tiger is extinct, these two are the most highly endangered ones, right? Right?

    And if Joy R. is reading this, and has any influence over Series 3 critters: please, please — ostrich!

    Wasn’t there an ostrich in Series 1?

    I wonder why that is. I mean, other hypercarnivorous lineages throughout history, like dromaeosaurids, for example, vary somewhat in their overall morphology. I’ve heard its due to the fact that in cats straying too far from the basic felid bodyplan tends to have dire consequences for the species due to the way cats are specialized, but I don’t know why it is so strict for cats.

    Cats do vary. Their size variation isn’t much smaller than that of dromaeosaurids, and if you add Dinofelis, Smilodon, Homotherium and the tyrannosaur-like Xenosmilus to the present diversity, you arrive at comparable or higher disparity than that of dromaeosaurids at any particular time in the Cretaceous.

  15. #15 Darren Naish
    September 7, 2010

    Many thanks to all for comments. If you liked these articles (or, at least, found them interesting), it’s mandatory that you watch series 2 of ING yourselves. A few responses…

    Jerzy (comment 8): indeed I cannot find any pictures of lions or tigers raking prey with their pedal claws (indeed, big cats prefer to keep their hindfeet on the ground while attacking prey), but I was referring to cats in general. Smaller cats will ‘rake’ with the pedal claws while restraining prey with the mouth and forelimb claws. They do the same when fighting with conspecifics.

    Joy (comment 12): on the human pharyngeal configuration (combination of descended larynx and short velum [soft palate] that doesn’t overlap epiglottis)… I should have noted that the deer and cats with descended larynges still have overlap between the velum and epiglottis (and hence are unlike humans), in cases because their velum has become unusually long. However, in case anyone thinks that the human configuration is unique to our species, velum-epiglottis contact is not present in chimps (Nishimura et al. 2003).

    Furthermore – - does anyone know what the deal is with walruses? There’s an extensive literature on the cranial anatomy (and vocal abilities) of walruses, but I can’t find a definitive statement on whether they exhibit a ‘human-like’ condition: they clearly have both a descended larynx and a short velum, and the only diagram I’ve seen of a walrus pharynx in section (Tyack & Miller 2002) shows a human-like condition where the velum does not reach the epiglottis.

    And, to those wondering why pinnipeds can’t talk if they have such human-like palates and throats, the answer is… they can.

    Refs – -

    Nishimura, T., Mikami, A., Suzuki, J. & Matsuzawa, T. 2003. Descent of the larynx in chimpanzee infants. Proceedings of the National Academy of Sciences 100, 6930–6933.

    Tyack, R. & Miller, E. H. 2002. Vocal anatomy, acoustic communication and echolocation. In Hoelzel, A. R. (ed.) Marine Mammal Biology: An Evolutionary Approach. Blackwell Science (Oxford), pp. 142-184.

  16. #16 Dartian
    September 7, 2010

    Darren:

    Molecular data indicates firm inclusion of the Snow leopard within Panthera. However, because it differs in throat anatomy, skull shape, tooth shape and limb proportions from definite Panthera species (in some respects it’s rather cheetah-like), some anatomists argue that the Snow leopard warrants placement outside of Panthera and still use the name Uncia uncia for the species

    And, indeed, in contrast to molecular data, which usually recover a snow leopard – tiger clade (e.g., Davis et al. (2010)), analyses of morphological data tend to consistently place the snow leopard as the sister taxon to the other Panthera.

    some viewers were a little disappointed to see that the matter of how lions and tigers can be differentiated wasn’t really elucidated. But perhaps that’s because the two are extremely similar

    I think you just answered your own question. Osteologically, lions and tigers are very similar indeed. There are subtle, relative differences between them, but they are not easy to detect on visual inspection alone.

    lions are part of a ‘spotted clade’ that also includes leopards and jaguars, while tigers lie elsewhere

    Actually, it would be more appropriate to say that the entire Felidae forms a (primitively) ‘spotted clade’. The majority of extant felids are either spotted, or uniformly coloured descendants of spotted ancestors. Striped felids are decidely in the minority; they’re represented by the tiger and by some species of Felis sensu stricto, and that’s pretty much it.

    does this explain why there are so many claims of Barbary lions being ‘discovered’ in captivity?

    Crikey, that’s a good question! (I’m ashamed to admit that I’d never even thought of that possibility before you brought it up.)

    Reference:

    Davis, B.W., Li, G. & Murphy, W.J. 2010. Supermatrix and species tree methods resolve phylogenetic relationships within the big cats, Panthera (Carnivora: Felidae). Molecular Phylogenetics and Evolution 56, 64-76.

  17. #17 Andreas Johansson
    September 7, 2010

    And, to those wondering why pinnipeds can’t talk if they have such human-like palates and throats, the answer is… they can.

    I presume you mean “talk” in the sense parrots can, here?

  18. #18 John Harshman
    September 7, 2010

    I think it’s unlikely that dinosaurs were as low in diversity as some palaeontologists imply.

    Finally, an opportunity to hijack the thread into archosaurs. My favorite references on non-avian dinosaur diversity:

    Dodson, P. 1990. Counting dinosaurs: How many kinds were there? PNAS 87:7608-7612.

    Fastovsky, D. E. et al. 2004. Shape of Mesozoic dinosaur richness. Geology 32:877-880.

  19. #19 Darren Naish
    September 7, 2010

    Curse you Harshmaaaaan!!! (shakes fist). There’s also…

    Wang, S. C. & Dodson, P. 2006. Estimating the diversity of dinosaurs. Proceedings of the National Academy of Sciences 103, 13601-13605.

  20. #20 David Tana
    September 7, 2010

    Dr. Naish,

    these posts on both series 1 and series 2 of Inside Nature’s Giants have been great. I’m in the States and don’t have cable television, so I might not heave heard of the program if it weren’t for your reviews. Thanks a million!

    Are you sure you won’t cover the squid episode when it airs? I know you’ve strayed from tetrapods before for other vertebrates, and can understand if molluscs are really not Tetrapod Zoology material, but I’m sure you’d do them justice regardless.

  21. #21 Nathan Myers
    September 7, 2010

    I was starting to despair that Joy R. wouldn’t be in this episode, but there she is in the final still. My kids (8 and 10) jump up and down with excitement about each episode in this series, and are among her great admirers.

    I have to admit that my kids’ attention and mine flags during the Dawkins bits. It’s not what he says, it’s the way he says it — as if he’s trying to convince us of something he thinks we’re too thick to pick up on the evidence of our own eyes. There are certainly such people, and a very few of them will be in the audience, but his tone won’t win them.

    This episode doesn’t appear to be on YouTube yet. Any idea when it might get there?

  22. #22 Joy Reidenberg
    September 7, 2010

    Darren:
    The normal non-human primate condition is velum-epiglottic contact. There are numerous live experimental studies that show this to be the case (see, e.g., Laitman et al. articles). The one you cite is the only contrary one, and I suspect that is because it shows temporary unlocking during swallowing and perhaps during some vocalizing, but at rest it definitely locks back into position.

  23. #23 Joy Reidenberg
    September 7, 2010

    Darren (comment 15):
    I haven’t dissected a walrus yet, but I can say that elephant seals and other pinnipeds have a pretty typically highly placed larynx, with velum-epiglottic overlap.

    Nathan (comment 21):
    Send me your kids’ names and address to my e-mail and I will send your kids an autographed card!
    I’m so glad you waited for my cameos on the claws, jaws, and safari scenes! I was actually in charge of the tiger dissection while Tecumseh did the lion dissection. Unfortunately, due to the poorer condition of the tiger specimen (mostly post mortem decomposition), and the redundancy with the lion anatomy already being shown, much of the tiger anatomy didn’t make it into the final cut.

    David (comment 14):
    No, there was no ostrich, although we did do a number of African animals (elephant, giraffe, lion, crocodile, great white shark). I’m still keeping my fingers crossed for an emperor penguin or an emu though.

    Lionel (comment 13):
    I agree – a pinniped would be great! I’ve dissected harbor seals and sea lions, but I’d like to see a walrus or adult male elephant seal (I’ve only dissected juvenile elephant seals so far – adults males are just to big to ship back to New York!).

  24. #24 graham
    September 8, 2010

    Obligatory mention here of the fact that some workers regard P. tigris of tradition as consisting of three phylogenetic species. Under this proposal, the Sumatran tiger P. sumatrae and Javan tiger P. sondaica warrant separation (Cracraft et al. 1998, Mazák & Groves 2006).

    And now that the Caspian tiger is extinct, these two are the most highly endangered ones, right? Right?

    The Caspian tiger was probably not a distinct subspecies/ESU/whatever you want to call it, but an allopatric population of Siberian tiger, which is obviously still extant. P.(t.) sondica is now almost certainly extinct.

  25. #25 Dartian
    September 8, 2010

    David T.:

    Are you sure you won’t cover the squid episode when it airs? I know you’ve strayed from tetrapods before for other vertebrates, and can understand if molluscs are really not Tetrapod Zoology material, but I’m sure you’d do them justice regardless.

    The thing is, there is already another, moderately successful science blog whose owner is well known for having a particular affection for cephalopods; were Darren to write about giant squid, he might be stepping on that blogger’s tentacles toes…

    Nathan:

    my kids’ attention and mine flags during the Dawkins bits. It’s not what he says, it’s the way he says it — as if he’s trying to convince us of something he thinks we’re too thick to pick up on the evidence of our own eyes.

    Do you mean that your 8 and 10 year old kids are already so well versed in evolutionary theory and vertebrate anatomy that Dawkins’ narration insults their intelligence?

    As for Dawkins’ supposedly inefficient narration style in general; seriously, how would you prefer him to do it instead? By engaging in Steve Irwin-style histrionics?

    his tone won’t win them

    How do you know that?

  26. #26 David Marjanović
    September 8, 2010

    it’s mandatory that you watch series 2 of ING yourselves

    Not possible over here. :-(

    The thing is, there is already another, moderately successful science blog whose owner is well known for having a particular affection for cephalopods; were Darren to write about giant squid, he might be stepping on that blogger’s tentacles toes…

    Bah. PZ has more traffic than he knows what to do with, especially in his current reconvalescing state and his new teaching duties; and if he links to Tet Zoo, imagine how traffic here will go up when a horde of Pharyngulites will descend upon Tet Zoo!

    Really, it would be a win-win situation. :-)

  27. #27 Samantha Vimes
    September 8, 2010

    #26, when I come here, it’s usually from PZ’s blog. But via the sidebar.

  28. #28 Dartian
    September 8, 2010

    Bah. PZ has more traffic than he knows what to do with

    Détendez, mon camarade. I was just joking.

  29. #29 Darren Naish
    September 8, 2010

    Thanks for continuing comments; thanks especially to Joy for comments 22 and 23 on velum-epiglottis contact (or lack of it) in non-humans. Nishimura et al. (2003) – the study that reported a short, human-like velum that doesn’t contact the epiglottis in chimps – stated…

    The epiglottis, which is attached to the thyroid cartilage of the laryngeal skeleton, descended relative to the velum during the first year of life. It completely lost contact with the velum by at least 6 months of age, and the distance between them (the VL–EG length) increased during early infancy in all subjects (Fig. 3).

    Their study subjects were three living juvenile chimps.

    There’s no doubt that monkeys have full velum-epiglottis contact (e.g., Laitman et al. 1977); the Nishimura team have published other studies where they refer to lack of velum-epiglottis contact in chimps, but I have to say that the MRI scans I’ve seen of chimps (in various of Fitch’s articles) seem to show the velum and epiglottis as being extremely close (though not necessarily in contact), so maybe there’s room for doubt about this. In humans, distance between the velum and epiglottis is pretty variable, so maybe it is in chimps as well.

    Ref – -

    Laitman, J. T., Crelin, E. S. & Conlogue, G. J. 1977. The function of the epiglottis in monkey and man. The Yale Journal of Biology and Medicine 50, 43-48.

    Nishimura, T., Mikami, A., Suzuki, J. & Matsuzawa, T. 2003. Descent of the larynx in chimpanzee infants. Proceedings of the National Academy of Sciences 100, 6930–6933.

  30. #30 Nathan Myers
    September 8, 2010

    Dartian: You will find the answers to your questions in the text you quoted.. Dawkins channelling Steve Irwin would be an improvement, particularly if he were wrestling a crocodile at the time, but Joy would be quite up to his job (narrating, I mean, not channelling), and then Dick could stay home.

    What impressed my kids most was when Joy climbed right inside that whale.

  31. #31 Dartian
    September 8, 2010

    Nathan:

    Dawkins channelling Steve Irwin would be an improvement

    I brought up Steve Irwin in this discussion because I think that he is a good example of a ‘media spotlight biologist’ who arguably failed to get any real pro-evolutionary message* across to large segments of his viewership, or at least to those who would have needed that message the most. If you are a professional biologist and creationists love you**, it’s pretty safe to say that you’ve done something wrong. (Behind the flashy style, there was actual substance in Irwin’s programmes, but it was all too easy to miss because of all the showmanship.)

    * I actually also suspect, alas, that by and large, Irwin probably wasn’t really that successful in getting across his pro-conservationist views to laypeople either. But that’s another story.

    ** I don’t think that Ken Ham will ever write a respectful eulogy to Richard Dawkins when he eventually karks it.

  32. #32 Dartian
    September 8, 2010

    Something I forgot to ask earlier…

    Joy:

    Regarding the lion’s larynx, it is interesting that it is set so low in the neck. This really surprised me

    While performing the dissections for these two series, did you guys discover anything really novel? Something that has not been previously reported in the scientific literature, and that you are going to publish? (Heck, for some of the animals featured in ING, just publishing basic biometric data would already be of scientific value.)

  33. #33 Nathan Myers
    September 8, 2010

    Dartian: I see that we are in agreement, then.

    But does anybody know whether/when this episode is going to be posted on youtube? My kids are still asking.

  34. #34 Ranjit Suresh
    September 8, 2010

    Off topic: but, humped(!) quill knobbed Spanish carcharodontosaur Concavenator corcovatus seems to further push back the origins of feathers. It’ll be interesting to see if eventually the gap between Ornithischian and Tetanuran proto-feathers disappears altogether.

  35. #35 Mickey Mortimer
    September 9, 2010

    I gotta say that I didn’t find this episode as interesting as the others, especially those from season 1. This was largely due to the fact there was very little time devoted to the dissection and anatomy, with more time spent on behavior and live lions. Every other nature show is about living animals, so what I like seeing from this one are the internal differences and morphological details. I was looking forward to seeing the anatomical differences between lions and tigers, but while the show claimed it addressed this, they were never compared at all.

    I don’t want to be completely negative though, as in general the series is excellent and far more educational than other animal shows out there. Joy’s enthusiasm makes it that much better, and it’s great she’s commenting here too.

    I think I might be an outlier in that I would be interested to see episodes about more mammals as opposed to things like turtles or birds. This is ironically because the latter are more different than the standard human anatomy, so people like me who already have a general knowledge of comparative anatomy will already know the major points that will be covered (look forward to seeing air sacs, vertebrae fused to the shell, etc.). But an episode about an aardvark, hippo, giant anteater, seal, or even a small mammal (just rename it Inside Nature- I’d gladly watch four dissections a year of anything) would feature more things I didn’t know. That’s why the giraffe episode was my favorite- I had never really considered giraffe morphology before besides their long neck, but I learned so much about their anatomy from it.

  36. #36 Andreas Johansson
    September 9, 2010

    Hm. I’m presumably less clueless wrt anatomy than the average viewer, and I expect they could tell me plenty stuff I didn’t know if they did an episode on a human …

  37. #37 Neox
    September 11, 2010

    I’d just like to add my compliments to the makers and participants of the program for making a show so compelling I had, for the first time ever, write a note of appreciation to the broadcast channel.

    Keeping my fingers crossed for more seasons. An ostrich or emu as mentioned in the comments would be lovely and fit with the theme. When I sat speculating on future shows, I figured a bison might be a fitting subject as well, and possibly not that hard to come by, given the farmed stocks in the US.

    Thanks to you too, Mr Naish, for a very informative blog.

  38. #38 zlg
    September 12, 2010

    Great write up! I don’t have t.v., so I probably would have never heard of ING if I hadn’t come across this. I’ll have to find a way to watch it. I would like to see a dissection of a Capybara. They may not be as big as a tiger or elephant, but come on, giant rodent!

    I brought up Steve Irwin in this discussion because I think that he is a good example of a ‘media spotlight biologist’ who arguably failed to get any real pro-evolutionary message* across to large segments of his viewership, or at least to those who would have needed that message the most. If you are a professional biologist and creationists love you**, it’s pretty safe to say that you’ve done something wrong. (Behind the flashy style, there was actual substance in Irwin’s programmes, but it was all too easy to miss because of all the showmanship.)

    * I actually also suspect, alas, that by and large, Irwin probably wasn’t really that successful in getting across his pro-conservationist views to laypeople either. But that’s another story.

    ** I don’t think that Ken Ham will ever write a respectful eulogy to Richard Dawkins when he eventually karks it.

    I don’t know if I would consider Steve Irwin a “professional biologist” considering he never went beyond a high school education (and there’s nothing wrong with that in my opinion). Just because he had a t.v. series about animals doesn’t mean he was obligated to have a pro-evolutionary public service announcement every episode. What he did do was get people interested in and excited about animals. That’s the first thing people (especially kids) have to become before they care about conservation. The zoos I’ve been to put a much larger emphasis on conservation than evolution (if they even talk about evolution at all), but does that mean they are failures because creationists don’t boycott them?

  39. #39 Dartian
    September 13, 2010

    Zig:

    I don’t know if I would consider Steve Irwin a “professional biologist” considering he never went beyond a high school education

    His formal education notwithstanding, Steve Irwin actually did have an academic publication record. He has published a number of peer-reviewed scholarly papers on herpetology. (This is not widely known and it comes as a surprise to many – which, from the point of view of the argument I was making, is rather telling – but Darren has mentioned it here on Tet Zoo; see this article and the comments on it.) That, together with his self-promotion as an animal conservationist, makes me willing to consider Irwin a ‘professional’ biologist. Though I admit that he’s a bit hard to classify.

    Just because he had a t.v. series about animals doesn’t mean he was obligated to have a pro-evolutionary public service announcement every episode.

    Irwin did not really have a TV series about animals. He had a TV series about himself. The various animals were, at most, his co-stars.

    That’s basically the problem I have with Irwin’s way of doing things. Admittedly entertaining though they could be, his shows tended to reduce living, wild animals to little more than Reality TV entertainment (I hasten to add that I do not for a moment think that Irwin himself actually thought like that; it’s just that that’s the impression that all too often and easily was conveyed to viewers). Beyond the rather unsurprising fact that snakes/goannas/crocodiles/whatever don’t particularly enjoy being chased and manhandled by humans, what do you think that the average layperson does learn from a typical Crocodile Hunter episode? A deeper understanding of biodiversity, of ecological complexity, of evolutionary relationships? Or ‘Wow, that fucking thing almost bit Steve’s arm off!’? Irwin, not the animals, was always the main attraction of the Crocodile Hunter.

    Or, to put it differently, you could easily watch Irwin’s shows and walk away reaffirmed in your belief that animals were put on Earth by the gods for the purpose of providing entertainment for us humans. Hence Irwin’s popularity among creationists.

    What he did do was get people interested in and excited about animals.

    And after Irwin’s death, some of those people mutilated and killed sting rays in ‘revenge’. It’s pretty clear that Irwin’s earnest pro-conservation message, too, was totally lost on some segments of his audience.

    The zoos I’ve been to put a much larger emphasis on conservation than evolution (if they even talk about evolution at all), but does that mean they are failures because creationists don’t boycott them?

    Well, I personally think that all too many zoos miss many good opportunities to educate people about evolutionary biology*, so in that sense, yes, they are ‘failures’. (But then again, zoos as we know them were not originally intended to be either scientific institutions or conservation centres. Zoos/menageries were intended as entertainment and as places where people could go and gawk at weird and wonderful beasts. It wasn’t until well into the twentieth century that zoos – or the better zoos, anyway – reinvented their main purpose to be one of conservation.)

    * Speaking of zoos, Steve Irwin’s ‘own’ zoo, Australia Zoo in Queensland, suffers somewhat from the show business syndrome. That was the impression I got, anyway, when I visited that place in March 2007, a few months after Irwin’s death. There were some good exhibits there, but there were also stuff that made the place seem more like a circus than like a serious zoological park. And, again, it was obvious that Steve Irwin, rather than the animals, was (even posthumously) the main attraction of that place.

    Finally, as I realise that what I wrote above may seem unfair or harsh: I’d like to emphasise that I have not intended to criticise the man, but his methods. For the most part, I actually liked Steve Irwin, and I would never question that his intentions were fundamentally good. But I also believe that his legacy is, for various reasons, a mixed one, and that it can – and should – be open to reassessment.

  40. #40 mo
    September 13, 2010

    How can I watch this in Germany? I don’t need German dubbing. Are there DVDs of the show yet?

  41. #41 Stewart Macdonald
    September 17, 2010

    Does anyone know where the closeup footage of the lion running through the grass (with the camera tracking alongside it) came from? I’m assuming it was of a captive animal.

    And, judging by the ratio of female to male students in the audience, I’m thinking I should have done vet science at uni.

  42. #42 kittenz
    July 3, 2011

    Re: cats’ use of their pedal claws.

    Cats don’t typically use their pedal claws to disembowel PREY, but they DO sometimes disembowel other creatures with their pedal claws – usually other cats, during intraspecies fighting. I’ve patched up many a gut-ripped cat – usually toms – with injuries to the underbelly, inflicted by the back claws during fighting. In a fight, each cat tries to flip over onto its back, so it can get those pedal claws into play. Their backs are very flexible, and their hind limbs extremely strong, so they can deliver a serious of vicious kicks, using the pedal claws like spring-wound razor blades.

    Occasionally I see dogs injured by cats in this way, too; for instance, a hound that has tangled with a bobcat will often have serious wounds to the belly, caused by those devastating pedal claws.

    Although cats quite deliberately rake the belly of opponents during fighting, they don’t typically attack prey in the same way. But the pedal claws do allow the cat to “hang on” when they attack prey larger than themselves. They can inflict terrible wounds on the flanks and hindquarters of prey as they dig in with the pedals to anchor themselves so that they can more efficiently engage the forearms and teeth for the killing bite.

    I believe that the pedal claws perform an important function in locomotion, not just the obvious one (climbing), but also in leaping, allowing the cat to “push off” with more accuracy than animals with unretractable pedal claws. Certainly cats whose rear claws have been removed are not nearly as proficient in leaping as cats with their claws intact. Of course, declawing actually mutilates the foot; the third phalanx is removed at the last joint of the toe. The difference in the declawed cats’ leaping abilities may be a function of the mutilation. But compared to, say, dogs, cats leap with much more strength, accuracy and grace. Could that be (in part) because as they leap, each pedal claw extends & engages the surface independently and gives the brain that much more information to accurately judge and complete the leap?

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