Our Ancestors’ Love-Hate for Sabertooths
Hominids have a long story in common with sabertooth cats. The earliest members of our own zoological family were vegetarians that fitted quite nicely with the role of sabertooth prey. Not a very important prey at that, because as a source of meat ungulates have always been more important, so our early ancestors such as Ardipithecus and Australopithecus would only occasionally figure in the menu of felids like Dinofelis, Megantereon or Homotherium. Even so, their life in the African forests of the Pliocene period would be always marked by the fear of the dagger-toothed felids.
But things changed in the Pleistocene. The appearance of our own genus, Homo, meant the entrance of hominids to the carnivore guild, probably as timid scavengers at first, but with an ever more assertive attitude as they developed a more sophisticated use of stone tools and a greater body size. By the time when the species Homo erectus (or Homo ergaster, as some specialists call the African populations) appears, hominids have become a force to reckon with among African predators. The leopard-sized sabertooth Megantereon was one of the most efficient hunters of the wooded savannahs, but as a solitary cat it had little chance to defend its kills against a well organized gang of the tall, aggressive and object-throwing hominids.
Did this relationship develop into a full-fledged kleptoparasitism? This term means that one species regularly steals the food from another without any benefit to the provider. Evidence is very complex to interpret, but current views tend to support this notion. In fact, if pressure from hominids got too heavy it might even contribute to the final extinction of this felid. There is interesting evidence, nonetheless, suggesting that now and then one hominid paid his bravery with dear life during such conflicts…
Even more complex is the possible relationship between species of Homo and the larger sabertooth cat Homotherium, which not only was as big as a lion but probably had some kind of social structure.
The possible implications of the uneasy coexistence between Dinofelis, Megantereon, Homotherium and our own relatives are discussed at some length in my upcoming book, “Sabertooth”. For those more technically minded, here is a link to an academic paper where we discuss in depth the coexistence between Homotherium and hominids in the Pleistocene:
http://www.mediafire.com/?35c93nyk23u3lr8
Here is a hypothetical scene where the sabertooth Megantereon whitei tries to defend its kill (a waterbuck antelope) from a gang of Homo erectus. I am sorry to say it doesn´t look good for the cat…
A Clash of Titans: Lion Vs Scimitar-tooth Cat
A former “pet theory” about the sabertooths was that they were specialized for hunting giant, slow and thick-skinned prey, and that when those herbivore behemoths went extinct, the sabertooths found themselves unable to capture the faster, smaller prey such as horses and antelopes. Then sabertooths went extinct, while the modern cats triumphed, because the latter were fast and smart and so they could chase and even use group tactics to catch the fast prey animals.
So the thory went, but it was largely based on the observation of the fossils of Smilodon, which is the heaviest, most robust of the sabertooth cats. Even for Smilodon the theory is certainly wrong, but the fact is that also in the Pleistocene there lived another kind of sabertooth: Homotherium, the so-called scimitar-tooth cat. In the Old World, Homotherium coexisted with the lion for many thousands of years, and when one compares the anatomical structure of these two top predators there are quite a few surprises to be found:
Homotherium was not a slower or heavier animal than a lion. In fact it was on average a lighter animal, especially when compared with the Pleistocene lions of Europe that were larger than their modern counterparts. You can see that difference at a glance looking at the drawing below, where both animals are shown to the same scale: the Pleistocene lion is shown at left (life outline on top, skeleton at bottom) and Homotherium at right. Homotherium had comparatively long forelimbs, and its wrist was narrower, better adapted to running and less adequate for handling prey.
The claws of Homotherium were smaller and less retractable than those of the lion, except for the large dew-claw, as happens with the living cheetah, again adaptations for sustained running rather than grappling heavy prey.
The teeth of Homotherium were precision tools perfect for cutting the throats of large prey animals, but given that each individual cat was more of a runner and less of a wrestler than an individual lion, there is one clear implication: in order to hunt the animals that its teeth were adapted to kill, a cat with the limb anatomy of Homotherium almost inevitably had to hunt in groups.
The size of the upper canines limits the diameter of the necks of prey animals that Homotherium could bite, so it is clear that it would not hunt adults of giant species such as proboscideans, rather it would target animals within the high part of the size range of the prey taken by lions, that is: large bovines, horses and the young of the giant species.
So we see a lot of overlapping and potential competition with lions, more so than the old cliché of the sabertooths as slow brutes would have us think. So now new questions arise: how did those animals avoid the worst of competition for so many thousands of years? And how did the lion manage to survive the crises of the Pleistocene that killed off the sabertooths and so many other species of large mammals?
Those are good questions indeed… and evidence points to some rather surprising answers. That evidence is discussed at some length in the upcoming book “Sabertooth”. Stay tuned!
In the Shadow of the Sabertooths
There is a popular misconception that sees the sabertooths as older, primitive relatives of our modern big cats -even as their ancestors. But the fact is that both lineages share a common ancestor that lived more than 20 million years ago, and since then they have evolved independently. Actually, the feline cats have changed much less in the course of all those millions of years, and they resemble that common ancestor more closely, so, ironically, it is the sabertooths who became more specialized, and our felines that remained more “primitive”.
One striking snapshot of the evolution of the two cat lineages (sabertooths and felines) is provided by the exceptional sites of Cerro Batallones in Madrid. This complex of fossil sites of late Miocene age (about 9 million years ago) has yielded an amazing treasure of fossils of carnivores, including the best sample in the world of 2 species of sabertooth cat, Machairodus aphanistus and Promegantereon ogygia. Machairodus was the first sabertoothed felid to reach the size of a lion, and it had a range of prey animals to choose from, including horses, antelopes, jiraffids, rhinoceroses and maybe even young mastodons. Such variety of herbivores would offer suitable prey for a modern big cat such as a lion or tiger, and one wonders: where were the ancestors of our big cats in the late Miocene? Well, the answer is they were right there, sharing the same ecosystems, but they certainly were not competing with the sabertooth for prey… because none of those felines was larger than a lynx!
Yes, the feline cats lived in the shadow of their sabertoothed cousins for many millions of years just like mammals lived in the shadow of the dinosaurs. And we are finding there was more variety of them than we used to think. For years we assumed that all the fossils of small cats from Batallones belonged to Felis attica, a serval-sized species commonly found in the late Miocene of Eurasia. But when a team of paleontologists led by Manuel Salesa from the MNCN in Madrid set out to study those fossils in more depth, we found some surprises.
As it turned out, most of the small cat fossils from Batallones belonged to a different genus and species (a new one, by the way) , Styriofelis vallesiensis, which differs from Felis attica in retaining more teeth (a primitive feature) and being slightly smaller, and which would have been rather similar to a modern wildcat. During the same study, we took a close look at fossils of the common species “Felis attica” and we found that it differed so much from modern species of the genus Felis that it was impossible to keep it in the same genus, so we created the new genus Pristifelis for those Miocene cats. Now the interesting thing is that several postcranial fossils from Batallones are slightly larger than those of Styryofelis vallesiensis and indicate the simultaneous presence of Pristifelis at the site. This combination reminds me of the situation in the modern African savannah, where the african wild cat and the serval cat share the same ecosystem with the cheetah, the leopard and the lion. In the case of Batallones, the big cat niches were firmly held by the sabertoothed species, and the felines were restricted to the role of rodent and bird hunters, a situation that would remain that way for millions of years until the late Pliocene. By that time, some felines evolved into full jaguar-sized beasts and for the first time they challenged the sabertooth supremacy. What led to such dramatic developments? Well, that is a different story…
Here is an illustration showing the small feline cat from Batallones, Styriofelis vallesiensis, to the same scale with the sabertooth Machairodus aphanistus. Even I was surprised by the size contrast when I put these two together!
And for those more technically-minded here is a link to read a PDF of our scientific paper about the Batallones small cats:
Meet an early “extreme” sabertooth: Eusmilus sicarius
Sabertooth predators evolved at least 5 times independently among mammals. Among them, the first group to attain all the extreme adaptations that we associate with the sabertooth “model” were the nimravids, a family of true carnivorans that thrived in the Eocene and Oligocene periods. Almost 30 million years ago (when the ancestors of more familiar sabertooths like Smilodon were only ocelot-like creatures chasing smallish prey in the forests of the Old World), the nimravid lineage of Eusmilus had already acquired all the “sabertooth” adaptations to the limit or nearly so. With the body size of a large leopard, the american species Eusmilus sicarius was a giant among the carnivores of its time. Of course it had enormous saber-like canines, but it also had other attributes that we see in other specialized sabertoothed predators: a huge downward projection on its chin; large incisors arranged in an arch well ahead of the canines; an enormous mastoid process for the attachment of powerful neck muscles that aided the animal to sink its sabers into the flesh of prey; and quite a few other subtle features. Other families of mammals would make their own “experiments” with the sabertooth adaptations, but this nimravid was the first to achieve this level of sophistication. And yet the nimravids disappeared without descendance near the end of the Oligocene. The cause of that extinction is a great mistery, but certainly it is not a unique episode. Sabertooth predators have evolved time and again with enormous success, becoming the top predators in several continents, and each time they have been wiped off the face of the Earth. In a way, they died of success, something that should give us humans food for thought. But that is a different story…
And here is a life reconstruction of Eusmilus sicarius, the apex of sabertooth ev0lution in the Oligocene of North America. The animal was about the size of a large leopard. Some paleontologists think this species does not belong in the genus Eusmilus but rather in Hoplophoneus, but while we await for this matter to settle I will use the traditional name here.
A CALL FOR ADVENTUROUS ARTISTS!
How would you like to join me in a safari to the Okavango delta in search of the big cats? A few months from now I will be returning to Botswana (after all those years) and I would love to recruit a group of artists and big cat lovers in general who want to take part in a unique experience (painters, illustrators, animators… or anyone wishing to take a deeper-than-skin look at the most wonderful predators on Earth). I will try to share with you what I have learned over these 20 years about the anatomy, action, behavior and evolution of the big cats. And of course I look forward to learning from YOUR experience and background. The safari is organized by my friends from “The Elephant Trails”, a company based in Maun, Botswana, with a long experience setting the highest standards for photographic safaris. I will be announcing details soon, but in the meantime, think about packing your sketch pad and cameras, and get ready to come face to face with the big cats!
The safari departs in september 2013. You can download a PDF with information about the trip in the following link:
http://www.mediafire.com/view/?57ion6791h622hf
A time between two Worlds
One of the most fascinating aspects of studying the faunas of the Pliocene and Pleistocene of Africa is the intriguing mixture of modern species with others that have vanished forever. In many of the cave sites from the Sterkfontein Valley (South Africa’s “Cradle of Humankind”) we find fossils of several kinds of sabertooth cats (Dinofelis, Homotherium and Megantereon) together with those of various modern antelopes. In fact the ungulate fauna was of a rather modern type, and it is pretty obvious that the sabertooths, like any other big mammalian predators, would have to pick their prey from among the most abundant herbivores in the area.
As a jaguar-sized felid well adapted to life in wooded areas, Megantereon would have ample opportunity to ambush antelope as they crossed gallery forests on their way to drink in South African rivers. The scene depicted in my illustration, with a hapless bushbuck (Tragelaphus) caught under the powerful paws of Megantereon, is based on the fossil sample from the site of Kromdraai (one of the many Sterkfontein Valley cavities), where both animals are recorded. Is is just one example of the many interactions between extinct species and more familiar ones that would have occurred in those wonderful times.
With evidence like this in mind, I can’t help thinking that if Megantereon were alive today in places like Kruger Park in South Africa, it would find a prey base not terribly different from the one that was available back in the early Pleistocene. Certainly not so different that the predator would not find some suitable animals to hunt… Extinction often seems to be a matter of too many things going wrong at the same time – a sort of biological “Murphy’s Law”- and once the crisis is past, the world goes back to business as before -only several species short. How I wish I could look through a “time window” into that amazing time before the extinction of the sabertooths!
Sabertooth reconstruction or de-extinction?
These days we are hearing a lot about “de-extinction”, that is, the scientific process of bringing extinct species back via cloning their DNA. Sabertooths are among the species mentioned, because the last sabertooth species to disappear did it as recently as 10,000 years ago and their fossils do preserve some DNA. Does that mean we are going to see a real living sabertooth anytime soon? I very much doubt it, and given the details of the methodology, even if we ever see a “resurrected” sabertooth there will always be a lot of doubts about how much it resembles the REAL thing.
I find these possibilities really intriguing, but I do not for a moment think that they turn extinction into a reversible process, and while I am not “offended” by the concept of “playing God” my impression is that we should not overestimate our actual potential for “bringing back the dead”.
My humble job is to research the anatomy of fossil animals and their living relatives in order to create reasonable approximations of the appearance and action of bygone species. But whenever I see a living big cat in the wild I get a very strong reminder of how much more than just osteology is needed to make a living animal. One cannot overstate how final extinction is. If we lose the wild lions and tigers we will never fully know what it is that we lost, because even if we reintroduce captive born specimens to the wild in some future time, there are subtleties in the interaction of a species with its environment that will be lost forever. But if all that is left of a species is the more or less incomplete DNA of a dead individual… well, the prospect is not especially bright.
As exciting as the possibility of seeing “what happens” after such experiments may be, I have two things clear in my mind: one of them is that whatever comes out of the laboratory, it will only share a small fraction of its essence with the real thing that was lost; and the second thing (CAUTION, here I indulge in some poetry) is that if I were a sabertooth cat (meaning a sentient individual of one of the most sophisticated species ever to evolve) I would like to see the light of day in the wilds of the Pleistocene, to face my fate as a predator and to raise a new generation of my kind, but I would not at all love to be born as a result of an awkward experiment by some overfunded scientists with a misguided sense of curiosity. It is easy to forget that each animal (including ourselves) has only one life to live, and from that point of view, de-extinction for me has something in common with some of the worse aspects of animal experimentation.
Let us do what we can to prevent the extinction of living species, and about those that are gone, I am content to study what remains of them. I am happy that pencils and graphic tablets remain my harmless tools for “resurrection”.
Thanks for reading!
Sabertooth diaries 6: time to play with clay!
Reconstructing sabertooths is a very demanding task, but it is also a lot of fun: in fact sometimes it can look a lot like childplay, and never so much as when you are making scale models in clay for reference. I have made a lot of models of skulls and heads of sabertooths and of their prey animals so that I can see how the heads would look in different angles and under different light conditions. These days when I need an absolutely accurate 3D reference I model the objects directly in the computer, but for a more spontaneous (even crude) approach there is nothing like the good old clay -and honestly, it remains a much more fun and relaxing thing to do!
Now, a few examples:
1.- Here is a skull of Homotherium based in several specimens form Incarcal in Spain. At some 12 cm. long, this is conveniently toy-like sized, like the rest of the models here.
2.- Here is the skull of the marsupial Thylacosmilus, with some of its soft tissues in place (concretely, it has the masseter and temporalis muscles, the nasal cartilage, the whisker pad and the orbiculars of the mouth.
3.- Here is the skull of Barbourofelis fricki…
4.- Even more bizarre: the skull of the gorgonopsian Rubidgea:
5.- And yet another gorgon, this time it is Inostrancevia, andI have put some soft tissue on it…
6.- If sabertooths look strange, some of their prey can be stranger still. Here is the skull of one of Inostracevia‘s potential prey: Scutosaurus.
7.- And here is the skull (with some soft tissue on it) of an animal that was neither a sabertooth nor a very likely prey, but rather a potential competitor for the carcasses of the predators’ victims: the entelodontid Entelodon. These animals are called “killer pigs” by some, and looking at their heads one gets an idea that the name might just be appropriate…
Sabertooth Diaries 5: concepts you will not see in the book
When you start working in a book like “Sabertooth” you see it as a sort of limitless box where you will be able to put all your ideas on the subject matter. But as the project takes shape (and especially when the deadlines begin to loom in the horizon), you realize that many of your concepts will not find a place in the finished book. In fact, you may realize that MOST of your ideas will be left out!
In my case, a good many concepts never went beyond the stage of a crude pencil sketch. It doesn’t mean they won’t go beyond that stage: I expect to find them a home in some future projects, and it is my experience that a sketch may find its opportunity many years after its initial inception. Many of the illustrations that you will see in “Sabertooth” derive from discarded sketches originally intended for “The Big Cats and their Fossil Relatives” or other projects from the last years.
Now let me share with you a few of those concepts that didn’t make it to the book. Between them they span almost 20 years in total, but at some point I seriously considered to make each of them into a finished piece for the book.
1.-Here is a violent scene showing Barbourofelis as it gets ready to dispatch a hapless Syntethoceras.
2.-Here is a quick study of Megantereon leaping from behind some branches in pursuit of some unseen prey animal.
3.- Some more violence here: a scene based on the famous fossil skull of Nimravus with a wound apparently inflicted by the saber of a bad-tempered Eusmilus. I had to manipulate clay models of both skulls in my hands until I managed to position the saber of Eusmilus in the right angle to inflict a wound like the one seen in the fossil. And then the difficult part was to arrange the rest of the bodies of both animals (at least the front part of them) to fit with the relative positions of their skulls.
4.-Finally, here is a scene with a pair of Smilodon emerging from among the branches of a fallen tree as they stalk their prey.
THE ULTIMATE SABERTOOTH DOCUMENTARY -COMING IN 2014!
As you may have gathered from the content of previous posts in this blog, I think it is just impossible to unravel the mysteries of the sabertooths without an in-depth study of modern cats. For this reason, the work of naturalists such as Jonathan Scott (of “Big Cat Diary” fame) has been such an essential input and inspiration for my work in reconstructing those extinct predators.
Now I am proud to announce that Jonathan and I are preparing a documentary film that will bring together the fascinating findings of paleontologists with the raw power of first-hand observations of the modern felines in their environments, in order to produce new and surprising insights into the evolution and adaptations of the sabertooths and their living relatives. This is not just a film, it is an experience of ongoing research, and I am sure that the results of this collaboration are going to change the way we see these mighty predators – both living and extinct.
In order to complete the film we will be launching a crowdfunding initiative a few months from now, so that the documentary can be ready to premiere sometime in 2014. We will announce the dates in due course.
With my collaborators from “The Fly Factory” creating amazing 3D animations of the anatomy and action of the sabertooths and a team of professionals behind the camera and in the cutting room, this is going to be a truly eye-opening experience. Stay tuned!
You can watch an early trailer for the film in the following link (make sure to set the YouTube quality settings to HD!) :
Life reconstruction of the sabertooth cat Megantereon
