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Sabertooth Cat, Megantereon nihowanensisl
There are two kinds of “true cats.” Cat experts call one type feline or “modern” partly because they are the ones that did not go extinct. If you have a pet cat, it’s a modern/feine cat. This also includes the lions, tigers, leopards, etc. The other kind are called “sabercats” because this group includes the saber tooth. It is generally believed but not at all certain that these two groups of cats are different phylogenetic lineages (but that is an oversimplification).

It has been suggested for some time that the bite force mechanics for at least the most derived, latest (but, alas, still extinct) sabercats was less than modern cats. Specifically, this means that when the jaw and the maxilla are brought together by the major muscles that operate this system, the force of the bite is less in the sabercats. Another thing that has been suggested for some time is that among living (modern) cats, there is a fundamental difference in bite mechanics between the smaller cats (who have round heads) and the larger cats such as lions, who have squarer heads with more snouty faces.

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Lion skull
However, these assertions have not been as well tested because of a) a lack of live examples of sabercats to test the hypotheses on and b) lack of application of three dimensional morophometric modeling, which is the new thing in functional analysis of animal anatomical systems.

A recent paper, “Evolution of Skull and Mandible Shape in Cats (Carnivora: Felidae),” by Per Christiansen published in PLoS One gives us a new perspective on this. He has applied the morphometrics and come to some interesting conclusions regarding the evolution of bite force mechanics in cats.

This is pretty straight forward, so I’m going to bullet point it for you:


~ Repost from one year ago this month ~

  • Brain size varies allometrically (non in a one-to-one relationship) with body size that is different than the allometeric relationship of other featrues of the skull in the feline cats. This accounts for the difference in head shape between little kitties and big tigers and lions. The bite force dynamics and the overall strength of the bite force are not different (scaled to body size) across the feline cats. So we can throw that out.
  • Sabercats are fundamentally different from feline (modern) cats. Instead of having a strong bite force, they have the capacity to deliver a slashing, shearing force with their saber-like teeth. They were probably adapted to rip the prey’s throat out with one slice, or (though not suggested by Christiansen) to eviscerate smaller to medium sized prey.
  • The ancestral cats were probably more similar to each other, as this shift away from bite force and towards shearing action occurs during sabercat evolution and is seen in its most extreme form in the later forms.
  • This might have been an adaptation to needing to dispatch prey very quickly because of a predator rich environment (of, say, tyhe Miocene and early Pleistocene).
  • It is further suggested that this degree of specialization of the sabercats may have also made these species more vulnerable to extinction as conditions changed.

source

ResearchBlogging.org
Christiansen, P. (2008). Evolution of Skull and Mandible Shape in Cats (Carnivora: Felidae)
. PLoS One, 3(7)

Comments

  1. #1 Mike Haubrich, FCD
    July 17, 2009

    Slightly off-topic, I have been curious about where Nimravids fit here. Is it just that they have homologous structures in their jaws and “canines,” or do they share other phylogenetic traits that make them cloely related to cats? I had understood that they share more in common with bears than cats.