Top Ten Cats #4 – Smilodon sp.

An artists impression of Smilodon fatalis – note the thick-set, powerful body and limbs, bob-tail and those teeth, up to 7″ or 18cm in length! The slender face and squat profile of the head indicate it would have had little biting power though, but evidence indicates anchoring of the jaw to the neck muscles – much thicker set. So though it did not have as strong a bite as even a modern lion, Smilodon fatalis combined its neck muscles with its fangs, in the ‘canine-shear bite’ technique, allowing it to slice through flesh with ease for a quick kill. (Credit: Dantheman9758)

Not strictly speaking a species, Smilodon is a genus in the Machairodontinae family – essentially the sabre-toothed cats, in taxonomic identification we would indicate multiple species with an ‘sp.‘ after the genus, like in the title.

Again another throwback from my undergraduate days but there’s a perception of sabre-toothed cats, particularly since they allegedly had a penchant for hominid flesh, that they are ruthless, savage bullies. They are portrayed as these solitary, vicious, mindless predators and, actually there’s a decent amount of evidence that that is not the case at all and that they may have been a much more sophisticated cat than we give them credit for. A sophisticat, if you will.

Sorry, I couldn’t…I mean, when a pun just…Boom! In the face! You can’t NOT use it, no matter how bad.

So, Machairodontinae, we discussed those in the introduction article. It roughly translates to ‘dagger-toothed’ and it is a now extinct family of cats. Luckily for all you people terrified of being snuck up on by something the size of a small lion, built like a brick-shithouse and with teeth like swords, the Smilodon (roughly translates to dirk-tooth or dagger-tooth) genus is also extinct.

There are three known Smilodon species and, going in order from smallest to largest we have Smilodon gracilis, Smilodon fatalis and Smilodon populator.

A size comparison of the three Smilodon species. Smilodon populator, the largest, was probably not too dissimilar in height and length to a large male African lion, however it would have been nearly twice as bulky! Clocking in at up to around 400Kg. All of the Smilodon species were bulky. (Credit: Aledgn)

The most commonly known about species is Smilodon fatalis – already my lexiphilia is kicking in and Smilodon fatalis sounds like a James Bond villain, so I love them.

They are the species most commonly known about because a bunch of the buggers fell into the La Brea tar pits in California leaving behind a lot of beautifully preserved fossils as well as a huge amount of debate.

Now believe this or not – but there was once debate about the use of their iconic teeth. You see the thinking was that having canines that big, that long, you know how teeth are? They’ll shatter on a cold toffee…The thinking was they couldn’t possibly be functional. Some people wanted to propose a sexual selection reason for them, but then that fails to explain the total lack (or at least minimal presence – again debated) of what we call ‘sexual dimorphism’ – differences between sexes, of Smilodon individuals. Who was selecting? If there was selection why didn’t we see gradual change over time?

No, there is one sensible reason they had those massive teeth, and it ties in to why they have a stout body form, generally sloped (almost like a hyena) with a massively powerful set of forelimbs and a springy set of back limbs.

Smilodon is almost perfectly adapted for hunting megafauna – We’ve used that word before, it just means fuck-off massive animals, although technically anything bigger than a sheep is megafauna, including humans. The megafauna of the time of Smilodon, though, were a completely different class, consisting of true giants like the woolly mammoth.

A Smilodon fatalis skeleton – interesting skeletal features to note are flats and ridges (e.g. notice how flat the forearm bones are, and the big crest on the shoulder-blade) these generally indicate an area in which a lot of muscle was anchored, Smilodon would have had remarkable upper-body strength, likely to grapple the huge prey they were taking down. You can also see the small crest on the top of the skull, but the more prominent blades behind the skull at the top of the neck. Animals with more powerful bites have what is known as a ‘sagittal crest’ – a ridge that tends to run from the back of the skull toward the front to anchor their big jaw muscles. The relatively small crest on Smilodon fatalis implies a gentle bite with the ridges around the neck implying a good squeeze technique generated by powerful neck muscles, rather than jaw muscles. Like a chef with a knife, they let their blades do the work. (Credit: James St. John)

Smilodon gracilis was the first to come along, existing in the period around 2.5 million years-500,000 years ago. Smilodon fatalis followed around a million years later and survived all the way up the the Pleistocene extinction event, the so-called ‘Quaternary event’ around 10-15,000 years ago. Smilodon populator was the last evolved species, with the first evidence around 1 million years ago and, like fatalis, surviving until the Quaternary extinction.

One of the downsides of the evolution of those huge weapons, those piercing teeth, was their bite was not as strong as other cats. But ask a chef what they’d rather have for tearing flesh, a large, very sharp knife with little power and lots of technique or a smaller, blunter knife with more force and the answer is obvious.

How Smilodon killed its prey is debated but the throat bite is the most likely culprit. The ‘canine-shear bite’ being the preferred technique, allowing the cat to use its stronger neck muscles to aid in the cutting of the vital spots since its jaw muscles lacked the requisite strength.

Strength testing on the teeth shows them to be stronger than your average feline canine – an adaptation clearly intending them for use and not display. Paleopathological (looking for problems with old bones) analysis also reveals wear and tear around various aspects of the jaw muscles related to repeated strain.

They bit. A lot! They bit and stabbed with those teeth.

So gracilis came first but then fatalis apparently dominated the landscape of North America so much gracilis was forced further south. An isthmus, a land bridge, between North and South America opened up allowing for what is called the ‘Great American Interchange’ – causing a seismic shift, migrations of flora (plants) and fauna (animals) between the two previously separate continents.

Fossil evidence seems to indicate that gracilis moved there and eventually evolved into the also awesomely named Smilodon populator – sounds like a metal band.

Smilodon populator was the largest of the smilodon species and possibly the largest, bulkiest felid to have existed. Slightly larger than a lion, but carrying significantly more bulk, they were perfectly adapted to the huge prey items on offer in South America, and likely outcompeted the previous dominant predators, the Phorusrhacid or ‘terror birds’, to eventual extinction. Previous mega-predators, such as Arctotherium, a near two-ton, 15 foot tall bear, was extinct by the time populator arrived, giving it free reign.

An image compare of a Smilodon populator skeleton (credit: Javier Conles) and a sketech of the same animal (credit: DiBgd) Again note the flatness of the bones in the legs, and the ridges, around the shoulders, neck, and hips. These are all anchoring points for big, strong muscles. Populator would have been strong!

When I was first researching Smilodon for an essay back in my undergrad years one of the areas of debate that caught my attention was the question “Was Smilodon a social animal?”

There’s a lot of circumstantial evidence (mainly to do with sexual dimorphism – are a lack thereof) to suggest that there is the potential for permanent or semi-permanent pairing or small-grouping, but sociability is not something one associates easily with modern cats, never mind ‘primitive’ prehistoric cats.

The evidence for it is also circumstantial, namely that in Africa lions, the social cats, there is a likelihood to respond to distress calls from prey animals – Smilodon fatalis is found, significantly, around the tar pits of the West Coast of America, implying they, too are responding to distress calls either from their prey or potentially their kin.

There is also fossil evidence of healed injury in Smilodon skeletons, implying either a very quick recovery time (not impossible) or they’re being looked after by a social structure (also not impossible).

They are built more like ambush predators than social hunters but, again I have described their form as being ‘hyena-like’ and, tell me, are hyenas solitary?

Given the size and scale of the prey items we’re dealing with, I mean, one Smilodon fatalis compared to even a bison? and we’re not talking current bison, Bison bison (yup, real original binomial for that one) we’re talking the ancestral, and much larger Bison antiquus. You either have to kill quick or kill smart and I’m on the side of smart every time.

Kitten tax! As far as I know we don’t have many, if any, examples of Smilodon kittens on display so this is the best you’re gonna get. (Credit: La Brea Tar Pits Musuem – used without permission, contact us for removal)

For a lion-sized cat, with admittedly a fair bit more heft and bulk, to be taking down the kinds of prey fatalis were I find it difficult to believe there was no co-operation. Now whether there were packs, prides, as with modern Lions, is another matter. Personally I would favour small groups either mate-pairs and their adolescent offspring, or groups of adolescent males or females who hadn’t paired up yet.

This gives them a much greater chance of hunting success, the ability to manoeuver prey into ambush situations (as we do see with modern lions) and keeps things genetically simple, obeying Hamilton’s rule (that an individual is more likely to sacrifice its own genetic fitness for its kin, rather than more genetically different individuals).

Either way, going back to my intro you can see there’s a lot more to Smilodon than just an unthinking killer.

These are animals that still exist within human ancestral memory. Our awe at the majesty of the big cats today is surely linked to the fear and regard we once held them in when we were one of their prey items, though likely little more than a quick snack.

They are a species emblematic of the Pleistocene epoch, along with Mammoths, giant bears like Arctotherium, Megatherium – the giant ground sloth of South American, the Irish elk, the woolly rhinoceros.

I love the Pleistocene megafauna, it represents such a mad, dinosaurian era of mammalian evolution, when everything seemed to get big and weird. The enigmatic nature of Smilodon, those ferocious teeth, the unknown nature of their hunting behaviours, it is all so fascinating.

An artists depiction of a late Pleistocene scene in Northern Spain – Featuring woolly mammoth, woolly rhinoceros, European cave lions eating what looks like a reindeer, and some wild horses. (Credit: Mauricio Antón © 2008 Public Library of Science. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

And while the dinosaurs had their ‘Jurassic Park’, the best the Pleistocene has to represent it in popular culture is ‘Ice Age’. Not bad movies, by any means, but in no way are they trying to capture the awe and majesty of the creatures that existed in this period – A world of giants.

And the epoch associated with the 4th best cat of all time.

If I had to pick one I’ll go Smilodon populator. Chonky boi is best boi.

Did you miss our number 5 cat? Well go back and check out the Black-Footed Cat – one of the smallest felines in the world!

Or enjoy the majestic tiger, at number 3 right here.

Published by Karl Anthony Mercer

Like a dark-chocolate fountain at a weight loss party, Karl Anthony Mercer is an under-utilised river of bittersweetness. When not busy researching or writing about any and all non-fiction topics for 'We Lack Discipline' Karl can often be found walking, staring at wildlife or writing poetry.

18 thoughts on “Top Ten Cats #4 – Smilodon sp.

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