Caturday Special: Homotherium

A recreation of Homotherium serum, it is believed it was a plains hunter, and so would likely have had a very drab coat, much like modern lions. Most of the specimens I can see seem to be lacking tailbones so they are depicted with short tails. It’s a beautiful cat, that’s for sure. (Credit: Sergiodlarosa CC-BY-SA 3.0)

We covered the Smilodon species in our Top Ten Cats series. I don’t think that for abundance in the fossil record, size, shape, popularity or dem teefies there is a sabre-tooth cat that can match up to Smilodon. It was a genus that spawned three completely different species, presumably each having their own niche, and may have been the prehistoric American equivalent of today’s African and Asian Panthera species; lions, tigers and leopards.

Spongiformia squarepantsii – the literal Spongebob Squarepants, and it’s not even a spong, it’s a fungus. Biology – it’s basically one big joke at every living organism’s expense. (Credit: Tom Bruns at Mushroom Observer, CC-BY-SA 3.0)

They were from the subfamily of the Felidae, the Machairodontinae. If you remember that stupidly long word, it literally just means ‘sabre-teeth’ in complicatese. Such is the way with Latin binomials, the means by which every species is assigned a genus and species name. The funny thing is half of them mix up their Greek and Latin and some of them are just jokes – There’s a sponge-like fungus whose Latin name, I shit you not, is Spongiformia squarepantsii…Don’t ever let anyone kid you into thinking life science is a serious business.

The problem I have with Smilodon is they’re…Well they’re known, they’re everywhere, they’re culturally disseminated, their pop-culture fuel, they’re the meme and, I guess, no offence to my transatlantic cousins but, they’re American. We’re ‘We Lack Discipline’, we’re about the downtrodden, the underdog, the down-and-outs!

If Native peoples of the Americas claimed them as important as part of their heritage I’d be all for bigging them up, but instead a bunch of white dudes at the Smithsonian point to their skeletons and go “Aren’t they swell! You have a nice day now!” Before gulping down a quantity of fizzy drink so unimaginable they find it impossible to measure in millilitres so they measure it in the fictional wizardly units of ‘Oz’.

It doesn’t help a lot of the well preserved specimens come from the La Brea tar pits. Not only are they in Los Angeles, one of the global centres of vapidity, where a lot of America’s media writers are (if they’re not in New York) but they’re also in tar, which is basically thick oil so those United Statians must have a particular hard-on for them.

Apparently American mammoth and elephant species did not like swimming so much, and were very distressed to see their relatives do it.

Nah! It’s a recreation of a proposed tragic scene at the La Brea Tar Pits – some poor schmuck would get stuck, its friends and relatives would gather round making distress calls. This could potentially attract predators like wolves or Smilodon fatalis, of which we have numerous examples from the La Brea tar, and they’d be dumb and try and get the easy prey from the tar only to get stuck themselves. The tar then preserved the bones meaning we have some excellent fossils out of all this sticky stupidity. (Credit: KimonBerlin CC-BY-SA 2.0)

Sorry – It’s a lot of Yank bashing but over my few decades I’ve seen a quite noticeable drop in awareness and knowledge of our own native histories – Particularly when it comes to prehistory. Not only our knowledge base, but our cultures and our media themselves have all become this homogenised, Americanised mass. Everything these days is now owned by Disney, Amazon or Google – international conglomerates, for sure – but also very American.

Nuralagus rex – A 50cm tall hunchback rabbit that lived on Menorca until about 3 million years ago. (Credit: Goyo Arriaga CC-BY-SA 4.0)

It’s okay me talking about cave lions last week, and mentioning cave hyenas, and woolly rhinos and woolly mammoths but – most people just don’t know they existed here, in the UK, across Europe. Most people, shockingly, don’t even learn about the crazy array, the adaptations and speciations that occurred in mammals between the extinction of the dinosaurs and…around 13,000 years ago. It was a fucking marvel!

I’ll make some shit up and I bet it existed…

Horses as big as houses that ate other smaller horses, swimpigs, A sort of hippo but with a long dog’s snout, something like a catweasel (actually we have them today, they’re called civets and genets – feliformia, I may cover them one day), a cow that could glide!

Closely related to hippos, and known only through this titanic (about 85cm long) upper jaw/skull fossil, Andrewsarchus mongoliensis is literally a sort of hippo but with a long dog’s snout! It’s one of my favourite prehistoric mammals because…What the fuck even is this murder machine!? (Credit: Ryan Somma CC-BY-SA 2.0)

…All completely made up but you get my point. Set free from the tyranny of their reptilian overlords mammals did what young uni students do when let off the leash for the first time, they got hammered and experimented.

A skull of Archaeotherium caninus – you can tell from the teeth this thing is likely a predator, but what the fuck was it? Just effectively a hog the size of a cow with teeth to eat you with. Nothing to worry about. From the group of animals known as Entelodonts, this one shouldn’t worry you too much, they get bigger! (Credit: Steve Lew CC-BY-NC-SA 2.0)

Yet ask your kids, ask your friends, ask most people what prehistoric mammals existed and they’ll probably tell you Sid the Sloth, Manny the Mammoth, Diego the’ sabre-toothed tiger’ (THEY DON’T EVEN CALL HIM A FUCKING SMILODON!) and Scrat the weird sort-of squirrel thing. Why!? Because they were in the movie ‘Ice Age’.

The impact our cultural media has is stark. Persecution of sharks existed before 1975’s release of ‘Jaws’, but after 1975 – the scares, the panics and the inevitable impact on shark populations was noticeable. It was so significant that Peter Benchley, the writer of Jaws, went on to be a shark activist and helped fund marine research, including his own research boat, out of remorse!

Bless you, Google Images, for proving me right. The first images to show up when image searching ‘Ice Age’, not ‘Ice Age movie’ or ‘Ice Age cartoon’ – just ‘Ice Age’ – are of this movie and this one just happens to feature – ooh, the four characters I named above! The balance between making knowledge accessible and completely altering the public perception of something is a delicate balance. (Credit: AmaniTheLion1996 CC-BY-NC 2.0)

The ‘Ice Age’ movies were great for getting people interesting in the lives and species of animals in the prehistoric glacial period but most people don’t move on from there to learn more. They take the pop culture presentation as fact and move on.

So today, after that long-winded introduction, I want to talk about Homotherium. Like Smilodon, Homotherium is in the subfamily Machairodontinae. It’s a sabre-toothed cat. Unlike Smilodon, if you’re from Europe, Asia or Africa it was a lot more likely these awesome cats were terrorising the massive megaherbivores in your area. They also found their way to the Americas so, fuck off with your Smilodon dominance…Smilodominance?

Unfortunately they seem to be a little older than Smilodon and to have gone extinct around 10,000 years or so sooner.

The divergence of Smilodon and Homotherium happened around 18 million years ago. Phylogenies (where shit fits on the tree of life) and cladistics (where closely related species relate to each other) is complicated enough when we have genetics, but when all we have are bones it’s even harder.

It looks like the Homotherini (the tribe – an unofficial, linked group) to which Homotherium belonged was closely related to the Machairodontini tribe, particularly the species Machairodus – but whether Homotherini evolved from Machairodus or another, earlier, related common ancestor of the two is debated.

If We Lack Discipline’s First Rule of Everything is “It’s always more complicated than that.” Then our First Rule of Biology is “The real answer is we just don’t fucking know!” I’m fairly certain I covered this in my Introduction to Biology article. People who want certainty from science are asking for the improbable, but in astrophysics we have models that can tell us where massive celestial bodies will be, barring disruptive events, in thousands of years’ time. In biology, I can’t tell you what this fly on my windowsill will do next. Biology is diving headfirst into a world of chaos and accepting it. We just don’t know, likely never will, but have to try.

The skeleton of Homotherium venezuelensis. You can see the sharp, serrated teeth and the strongly prominent saggital crest on the skull. But also note the barrel chest (often indicative of a necessary lung capacity – i.e. for taking in a lot of oxygen) and strong-set forelimbs. This would have been a formidable hunter. (Credit: George Miquilena CC-BY-SA 3.0)

The general date given for the extinction of Homotherium is around 28,000 years ago – give or take. Again, we’re basing this off of tens of thousands of year old dead shit we dig out of the ground that was lucky enough to be preserved. The real answer is we just don’t fucking know!

There are four proposed species, Homoetherium latidens, H. ischyrus, H. serum and H. venezuelensis. I bet you can’t guess where that last one was discovered? Though, again, some argue that what we’re looking at is a disperse form of the same cat, others argue different species. See the First Rule of Biology again. Given the times and distances involved I’d have to believe some speciation occurred.

These cats were not lacking in size, naturally. Like most sabre-toothed cats their main prey would have been these outrageous megafauna, wild ox that make our domestic cows seem like sheep, mammoths, giant deer, etc. Most specimens are about 1.1m at the shoulder and clock a respectable near-200kg.

But there are better reasons to discuss Homotherium. I’m a predator guy so, yeah, it’s about killin’.

A recreation, and size comparison, of Homotherium serum – I have a few disagreements here. It is suggested the pelage, the coat, would have been quite drab as it was likely a plains hunter. This sort of rosette markings make it more akin to a leopard which also hunts from or near forest cover – although we don’t know for sure so their guess is as good as mine. The facts presented suggest is is the ‘lesser known’ cat and was considered ‘rarer’ but, again, it is lesser known because – let’s be honest, Smilodon has bigger teeth and so wins the PR war on fear alone. A lot of the fossils suggesting abundance of Smilodon come from a specific location (the La Brea tar pits) and some paleontologists suggest Homotherium was a lot more common than was previously believed and is merely scarce in the fossil record. (Credit: Dantheman9758 CC-BY-3.0)

I talked in my Smilodon article about how they may have hunted, and the debate about whether or not they may have been social cats.

Well Homotherium comes at ya with all the cool-cat adaptations. For one, about the size of a male African lion – that’s the benchmark of impressiveness of size, so – tick in the box there. For two, it had large, squared nasal openings. These, today, are only seen in the specialist speed and sprint predator the cheetah (Acinonyx jubatus) so it’s suggested it needed a large amount of oxygen – both for fuelling and cooling – like air intakes on a car. They also seem to have had non-retractable or semi-retractable claws, this is another adaptation seen in cheetahs that are evolved for speed.

Evidence from their skulls shows great development in their visual cortex. It had complex visual processing ability – this, I would argue, is usually done for one of two reasons. One is to keep your spot things to kill from a distance, and the other is to keep a sharp eye on things very close…You know…if you’re chasing them.

Identified as Homotherium crenatidens and one of many proposed Eurasian species of Homotherium it is believed they all, actually, are different populations of Homotherium Latidens. I’m not sure if you can make out the fine serrations on the amazing teeth, but you can see by the thick-set skull, and that prominent crest, this was a powerful biter – certainly more so than Smilodon that likely used technique rather than power for the kill. The youngest dated fossil of Homotherium was dredged up from the North Sea bed and is carbon dated as having lived around 28,000 years ago. (Credit: Jebulon Public Domain)

Already a dazzling combination of features but their trademark teeth – well, I’d love to tell you they were a two foot long and made of metal but that would be a lie. Whilst likely being some of the longest teeth in Eurasia and Africa they don’t have Smilodon beat. What they do have is serrations, multiple, smaller, sharp edges on their big teeth, like shark’s teeth! They also have a very prominent saggital crest – the bone that sticks out of the top of the skulls of carnivores to anchor powerful jawbones to.

We talked of the ‘canine shear’ of the Smilodon cats. Smilodon, when it hunted, was a species that needed a one-and-done kill, so its bite was intended to do that job. Smilodon were stout, muscular and powerful. It’s unlikely they chased much, and were more likely to be an ambush predator, where they did chase it was with the intention of getting close to some soft vitals and plunging those daggers in for the kill. Like a good chef, they didn’t use great power they let the knives do the work. Their saggital crests were less prominent, further back, and their strongest jaw muscles were anchored lower, or at the neck, implying a squeeze, a calculated slice, rather than a strong clamp.

A Homotherium sp. mounted in pounce-mode in Tianjin Natural History Museum. These cats were disperse and clearly exceptionally successful as evidenced by their range from Africa, across Eurasia into North America and even making it to South America during the ‘Great American Exchange’ with the creation of the isthmus, the land bridge, between North and South America. For all the credit we give Smilodon, they have only ever been found to have ranged in the Americas. These cats were worldwide! (Credit: Jonathan Chen CC-BY-SA 4.0)

Everything about Homotherium is different to that. It’s likely they were more slender, less powerfully built but – again, about the size of an African lion so hardly like prehistoric Tiddles is gonna sit on your fucking lap! The prominent crest suggests a powerful bite, but the serrated teeth suggest slashing, wounding. Whilst the Smilodon could not afford to make a mistake Homotherium possibly could, knowing a mistake will slow down their prey and they, with their big nostrils, can keep pumping air and keep up the chase.

A 2018 study showed their bite was likely similar to that of a lion. Their textbook, sabre-toothed sloped form and strong upper body do still suggest a powerful, dragger-down of prey. Their bite suggests a clamping, an attachment, a latching on.  

A snarling (or possibly flehmening?) recreation of Homotherium serum. Ooooh-ee it’s a pretty kitty. (Credit: Tim Evanson CC-BY-SA 2.0)

This and evidence of skeletons in close proximity (not potentially lured to a tar pit – the fossil grouping most responsible for suggestions of sociability in Smilodon) makes the question of sociability in Homotherium a pretty easy case. It likely was social, it likely hunted socially, using those serrated slashers like modern lions use their claws and bites – if you can’t drag the prey to the ground the first time you make sure you inflict enough wounds to slow it down. Unlike modern lions Homotherium have the equipment to keep a long, fast chase. They can chip away – death by a thousand cuts – but when the time came – SNAP! They’d clamp that jaw down on somewhere soft, squishy and vital, likely the neck and extinguish the life of their prey.

I can tell you now, as a fan of the deadly ballet, I’d love to have seen that hunt. Especially when they chanced on some really big prey. I bet that was a beautiful, savage bloodbath.

You want to know something more incredible? A huge find of Homotherium in the Friesenhahn Caves in Texas showed a number of cats of differing ages. If these cats weren’t social they sure had a penchant for hanging out in caves with one another! But there were also the bones of around 400 young mammoths.

A Deinotherium giganteum skull at the Oxford Museum of Natural History. It was a large elephantine creature with, as you can see, two large tusks for a beard! (Credit: Ballista by GFDL)

Yeah, in Africa they likely hunted Deinotherium, a now-extinct large prehistoric elephant, in Europe and Asia likely woolly mammoth was on the menu – they seem to have been well adapted to high altitudes and the cooler, northern climates. They were just well adapted full-stop!

In America these fuckers definitely ate mammoths, there are toothmarks on the mammoth bones found in the caves consistent with Homotherium. Of the Homotherium specimens we have found fewer have fractured canines than their Smilodon cousins. I think my model of their hunting holds up, if they got a shot for the kill they’d take it but otherwise this was a calculated chase, a chipping away, disable a leg, open a wound, cause blood loss, slow it down – work together! They weren’t weakly built and the number of bones in the cave suggests they would drag the prey back there to eat it. They had dinner with the family!

But it gets better, grimmer and bloodier.

In some cases it seems the mammoths had been dismembered before being taken back to the cave.

A Homotherium serum skull. One thing to note is the sharp carnanssial teeth at the back – clearly not adapted for crushing bone their eating must have been a delicate operation! No wonder they learned butchery! (Credit: James St. John CC-BY-2.0)

This is an evolution of division of labour. If you split the carcass then each member of the hunt can easily carry a chunk back to the den and you leave nothing behind and reduce the risk of having the whole carcass taken by competitors. A pack of wolves (and they would have had large, imposing dire wolves in some of their territories) or American lions (Panthera atrox, the largest of all lion species) comes at you to pinch your kill? One of you drops a haunch and the rest scarper with the other 3/4 of the kill. No fuss, no danger, it’s fucking smart.

It’s also butchery.

Homotherium? Smart and social sabre-toothed butcher cats.

Fuck yeah.

It’s Caturday! Kick back, relax, curl up into a purring ball and read more cats!

Top Ten Cats: Introduction – The basics of cat biology, evolution and natural history.
Top Ten Cats #10 – The Pallas’ cat – a small, very fluffy pika-hunter from Asia.
Top Ten Cats #9 – Jaguarundi – A unique and little known Puma relative.
Top Ten Cats #8 – Clouded Leopard – A stealthy and stunning Asian cat.
Top Ten Cats #7 – Jaguar – Beauty in spades, loves swimming, cracks skulls with teeth…
Top Ten Cats #6 – Lion – Emblematic, beautiful and social, an amazing cat.
Top Ten Cats #5 – Black-footed cat – one of the smallest, yet most deadly wild cats.
Top Ten Cats #4 – Smilodon – Going prehistoric with the sabre-toothed cats.
Top Ten Cats #3 – Tiger – One of the most gorgeous animals to have ever existed.
Top Ten Cats #2 – Cheetah – The placid lovechild of a sportscar and a murderer.
Top Ten Cats #1 – Domestic cats – Saviour of our foodstores and loving companions.

Caturday Special: The Origin Story – Proailurus and Pseudaelurus – The progenitor species of all modern cats examined.
Caturday Special: The Snow Leopard – The ‘Ghost of the Mountains’ gets an examination, a beautiful cat with some remarkable characteristics.
Caturday Special: The Scottish Wildcat – Once an emblem of so many Scottish clans, now this poor, cute, and feisty wildcat is struggling to survive due to historic persecution and current ongoing interbreeding with domestic cats.
Caturday Special: The Serval – Find out about this elegant and beautiful medium-sized African wildcat and how it has become part of our domesticated cat lineage!
Caturday Special: The Kodkod – The smallest cat in the Americas and endemic to only a small part of Chile and Argentina, find out about this amazing little boopster.
Caturday Special: The Feliformia and the Spotted Hyena – Did you know that hyenas are actually more closely related to cats than to dogs? They are members of sub-order of carnivores called ‘Feliformiae‘ or the cat-like carnivores. Learn more about them, the hyena and the hyena’s remarkable genitals here.
Caturday Special: The Cougar – The second biggest cat in the Americas is actually more closely related to your domestic moggy than the lion! Learn more!
Caturday Special: The Eurasian Lynx – One of my continent’s most handsome predators and one that certain groups are looking to get reintroduced to the UK after a 1,000 year absence in the hope it will control rabbit and roe deer numbers. I’m all for it!
Caturday Special: Hybrids – Looking at the phenomenon of hybrid species, with focus on cats like the liger, the pumapard and the Kellas cat, as well as some talk about domestic hybrids like chausie, bengals and caracats.
Caturday Special: The Fishing Cat – It’s a cat that loves to fish. An adorable little kitto from Asia.
Caturday Special: The Marbled Cat – A beautiful Asian cat of the Bay-Cat lineage that completes a write up of a cat species from every extant cat clade and that discusses the smaller, little known cats and why they are worth study.
Caturday Special: The Eurasian Cave Lion – A prehistoric beauty, around 10-15% bigger than the modern, African lion and as fearsome as it was admirable. Lions and humans emerged from Africa together and have a strong, cultural bond as a result. Like competing brothers.

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