I Can Has Slothburger?

2 October 2007

Smile!

Sorry. I couldn’t resist. Here’s the awesomely misleading headline from Science Daily: “Saber-toothed Cat Was More Like A Pussycat Than A Tiger.”

The new paper appears in the early online edition of PNAS: Supermodeled sabercat, predatory behavior in Smilodon fatalis revealed by high-resolution 3D computer simulation. The authors conclude that Smilodon did not have the bite strength of a modern lion, and probably didn’t kill large prey in the same way that lions do today–namely clamping down on the prey item’s trachea and waiting for it to asphyxiate.

Here’s how the lead author, Colin McHenry, visualizes the killing strategy of Smilodon, as quoted in the totally decent BBC article on the new study:

I think it was using its huge limbs and thumb-claws to wrestle large animals to the ground, and then when it’s got them there under control, that’s when the teeth come into play, and there’s one instantly fatal bite to the neck, severing the airway and carotid arteries to the brain. Death is more or less instantaneous.

You know…just like a “pussycat”!

Saber-toothed predators appear in several felid and non-felid lineages, including some marsupial lines (!), throughout the Cenozoic.  But, without any surviving examples to draw on, many, many, many hypotheses have been put forward about saber-tooth function and purpose.  The present modelling study is really interesting, but will hardly be the final word on the subject.

Brian wrote a piece on felid and nimravid saber-tooths a while back, and it’s well worth a re-read especially in light of the new paper.

4 Responses to “I Can Has Slothburger?”

  1. Zach Miller Says:

    I’ve always felt that there’s more to saber-teeth than just killing. In other mammals (primates, walruses, dogs, those weird extinct horned deer, elephants), enlarged canines have a strong social purpose, usually associated with threat displays. This is not, of course, 1:1 (walruses use their huge tusks to scrounge for food on the seafloor), but I’ve never seen a social theory for Smilodon’s great sabers.

    At a certain point, the canines would just be too large. Smilodon’s teeth are certainly beyond the level of practical. Sabers half that size would be enough to tear through prey’s vascular canals. I guess one of the things I’d want to know is whether, among saber-toothed felids, saber size is sexually dimorphic. I mean, think about it. Once the prey animal is dead, how do the damn cats EAT IT? Their canines get in the way!

  2. Laelaps Says:

    Just you wait Neil; I’ve got a long post all about bite forces and sabercats coming up (hopefully) tonight.

  3. Neil Says:

    Zach: Indeed saber-teeth look very much like they could be social structures. Van Valkenburgh and Sacco (2002) found Smilodon to be “significantly less dimorphic than living or fossil lions.” I’m not sure if anyone has looked at sexual dimorphism in other saber-tooth taxa. (I can send you that reference tomorrow.)

    Contrary to popular wisdom, sexual selection may not require dimorphism in all cases, but that’s a big tangent to go off into.

    As for how Smilodon might have eaten, if you watch big cats feeding on a large carcass you’ll notice they often eat with the side of their mouth (this picture shows it rather nicely) shearing meat off with their carnassials. Heavy wear on the carnassials of saber-tooth nimravids and felids suggest they did the same thing. Also, saber-tooths (saber-teeth?) tend to have larger gapes than their non-sabery relatives (Emerson and Radinsky 1980). (I can send you that one too).

    We’ll see what Brian has to say about all of this!

  4. Zach Miller Says:

    Yes, send me both, sir! I didn’t realize that cats tear off food with their premolars and molars. See, my two cats each with their heads stuffed in their food bowls, so I just assume they’re grabbing food with their incizors, even though I can’t see them. 🙂


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s