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.
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:
- 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.
I think that first picture is of a Nimravid (maybe Hoplophoneus). In which case its not a cat but from a separate family (Nimravidae).
No, it is a Megantereon.
We'll probably never know exactly why sabertooth cats went extinct but they were successful predators for millions of years across radically changing environmental conditions. Whatever drove them to extinction had to be more than just overspecialization.
Haven't Sabers evolved several times, going extinct and then another species evolving basically the same tactics?
Sabers (long [usually] canites) have evolved a number of different times in mammals (and fish, but that is almost certainly a different kettle of monkeys). The smilodonts and their relatives are one example, and the regular felid kittys is another (becauase there are probably some sabers in that group, such as the snow leopard, maybe). Ross mentions the Nimravids ... that is an example that is morphologically very much like the smilodon cats. There was a marsupial saber tooth "lion" as well.
The reason why each group went extinct is almost certainly because most groups go extinct.
I have loved this post on nimravids since it first came out at Olduvai George: Not Quite a Cat. Wasn't this supposed to be about whales?
Nimravids have an interesting history in North America. Throughout the Oligocene, they assumed all the predatory roles later taken by true cats. But by the beginning of the Miocene, 23 million years ago, they had all disappeared. For whatever reason, perhaps because there was an abundance of arctoid (doglike) carnivores of all descriptions present here at the time, there were no nimravids in North America for the next few million years. Felids also were missing and made their North American debut in the form of a small conical-toothed animal, Pseudailurus, about 17 million years ago. (Showing up to really confuse things a few million years later was a scimitar-toothed true cat named Nimravides! Got that? Barbours Cat is a nimravid, and Nimravides is a real cat! Aurgh!!!)
Greg, Why So Serious (about extinction?)
The mention of sabre-tooth marsupials compells me (sorry!) to remind you that I wrote about these animals - the thylacosmilids - at Tetrapod Zoology recently (here). Sorry to self-promote.
Incidentally, Per Christiansen has been giving talks where he referred to Neofelis, the clouded leopards, as sabretooth-like in some respects. I can't recall if his work on this taxon has yet been published however.
Mike: My point is simply really a reference to how we think about extinctions, and how we try to explain them. If one group goes extinct and the other does not it is almost always assumed (by non-extinction experts) that there was a difference between the two groups that accounts for one going extinct and the other not. But even if there was such as factor tht does not mean that if you re-ran history again that this factor would not play that role to that degree, and perhaps some other factor wold come into play (a little) and the OTHER group would go extinct instead.
The fact is that every one of the cats and cat-like creatures all became almost extinct or reduced significantly in number during the LGM and similar periods previously. During the Pleistocene, lions were very very widespread (possibly the most widespread carnivor ever) and after the LGM they were probably reduced to a few patches in asia and Africa (probably). Other large cats underwent the same kind of shift. Perhaps among large bodied canivores, anything that was really widespread had a small chance of surviving the repeated LGM's of the Pleistocene, and anything not widespread had almost zero chance.
This would tie in 'specialization' if specialization also links to heterogeneity and diversity/disparity.
Darren, thanks for noting that. That is definitely not self promotion, it is good linking.
> Got that? ï¿½Barbourï¿½s Catï¿½ is a nimravid,
> and Nimravides is a real cat! Aurgh!!!)
Barbourofelids are very nimravid-like at the first glance, but in fact they form their own, separate clade, wich might be closer to felids than to nimravids.
Christiansen published on sabretooth characters in Neofelis back in 2006 in the Journal of Morphology. I think its available online.
Also, are you sure its not Hoplophoneus?
Also, are you sure its not Hoplophoneus?
Interesting. I was going by what the site I took it off of said (seemed bot authoritative and copyright free). So now we have conflicting information. Who knows?
I am going to change the image to what I think is a less ambiguous case.
> Also, are you sure its not Hoplophoneus?
Then it would be a nimravid, not a cat. Nimravids and cats are only distantly related. Hyaenas are actually closer to cats than nimravids are, but still it is quite possible to confuse the skulls of nimravids and felids - at least if you have only pictures to work with. The degree of convergent evolution is really astonishing. As a rule of the thumb, saber-toothed nimravids and barbourofelids have mandibular flanges, and saber-toothed cats have not, but alas, that rule doesn't apply for *Megantereon*, wich has flanges in spite of being a felid.
I was curious; does anyone know what the dent or hole is on both the saber and lion skull that is directly below the eye? It looks pretty deep on the lion's; does that hole connect to the eye socket? It looks approximately where the whiskers would be, but I'm doubting that that is it's purpose.
Its called the infraorbital foramen and supplies nerves and blood vessels to the front of the face. Interestingly enough in lions from India it is split in two (bifurcated) whereas it is a single hole in African lions.
In wetlands and wet forest conditions, single large predators are apex (tiger, leopard), in savanna/plains conditions, pack predators are apex (lion, hyena, wolf) largely targeting weaker members of large herbivorous herds.
Sabertooths clearly indicate not-savanna specialization, they were not pack hunters on savannas, rather they shared some features with the clouded leopard of Borneo. They utilized soft substrata such as swamps, tar pits, (high soft snow? Note caribou females have been selected for antlers, deer shed their antlers at about snowmelt), to ambush from behind and trap prey, using the cat's weight on prey's back to slow down and exhaust the prey, especially effective in water. On savannas, ungulates need sharp thick horns and hooves, not branching antlers (like porcupine) which protect from attacks above-behind. The curling spiral horns in antelope are stronger than straight horns when head undergoes twisting.
As wolves dominated the plains, sabertooths were reduced to sparser wet forests. Unlike felines, canines can eat plant food and small game therefore could survive in the absence of large game, sabertooths could not and were decimated during extended drought, due to lack of breeding opportunities and territoreality.
Compare the puma/mountain lion vs the jaguar. Pumas attack headgeared ungulates in dry forests, jaguars (love water) attack non-headgeared (diving) tapirs, capybaras in wet forests, therefore they lack sabers. Sabertooths attacked non-diving prey. Water chevrotains dive to escape predators. Sabertooths succeeded when their prey stayed afloat at all costs. Moose are able to submerge, which is why their antlers have become more palmate/massive and less spiky, more impressive to the ladies.
Actually, Greg, I was just trying to slip in a reference to Joker from Dark Knight.
I have this project due January 19, 2009. I have to show the evolution of any animal or plant of my choice. I chose the cat. I was wondering if you could Email me some information that could be useful. I really need this project to be a good one. I have a C in science and i want to bring my grade up. Thank you.
hello i just watched a show on national geo where a study was being conducted on the bite of sabretooth tigres i dont know much abt these animals and i know this may sound stupid but what are the chances that the sabertooths didnt open there mouths to kill their prey what if they simply buried the long teeth and ripped with the neck muscles and causing fatal bleeding in their prey the same way a wild boar will rip and tear in defense they could have also kept their mouths shut and flayed the muscle off the bone before consuming it wouldnt this account for the weak bite force and the enlarged neck and shoulders kind of the same biuld as a wild boar all the brute force up front well i saw the show and was just wondering if this was a possibility. Thank You for your time.
The infraorbital foramina of both the lion and the sabre have been commented on. In humans the infraorbital foramina are tiny defects you couldn't squeeze a pencil through; so what is the functional significance of these animals having such large foramina in comparison to ours? The size difference is striking!
They are not defects. Generally, foramen are holes in bone through which blood vessels and/or nerves pass. As mammals evolved and skeletal tissues have reorganized in different groups (mainly at the "order" level) the distribution of blood vessels and nerves has also become organized in taxon-specific ways. Sometimes the difference is functional sometimes it is just chance.