After all these months and years working in the preparation of my book “Sabertooth”, the moment when I arrived to the Indiana University Press stand at the recent SVP meeting was an emotional one. It was the 29th of October and I met Bob Sloan, Science editor at the Press, who handed me a copy of the book. I had seen and corrected PDF versions of the thing many times, but holding the real book, feeling its weight, leafing through its pages, well, that is a different experience altogether.
There are of course those who claim that in the future all our reading will be done in screens, and that the printed book is a thing of the past… well, for me there is still something very special about a paper book, especially if it is an illustrated one. To celebrate its “physicality”, let me now share a few photos of my copy of “Sabertooth”. I know that copies have taken quite a bit longer than expected to ship from Amazon.com, and that people who want to order it through European branches of Amazon are still waiting to even know a distribution date, but they will not have to wait much longer… it is coming!
The more active you are in real life, the less time available to contribute to the blog. Some people seem miraculously able to avoid this inverse proportionality, but I am yet to find a way to do it… So, I have been unable to update you on many exciting things that have been going on lately. Now let me at least share the excitement of a new discovery by my paleontologist friends Jack Tseng, Xiaoming Wang and colleagues: an amazing collection of fossils of what seems to be the oldest pantherine cat known this far, coming from latest Miocene-earliest Pliocene deposits in the Tibetan plateau. A somewhat crushed but complete skull was the basis for may reconstruction of the life appearance of this new species of big cat, named Panthera blytheae by its discoverers. You can see the 2D illustration right here:
I have also uploaded a mini-video of the reconstruction process. Check the youtube link here:
Finally, here is a link to the academic paper describing the new species:
We are back from the “Drawing the Big Cats” safari experience, and there is an awful lot to assimilate from what we saw and lived during those action-packed days in Botswana’s wilderness. Every safari is different from any other, and it always gives you something different from what you were expecting. Among the things this safari has yielded which I did not dare to expect was a lot of quality time with big cat families, especially with the most elusive of them all -the leopard. We look at the big cats as predators, and thus we want to see them hunt, but this predatory fixation may make us forget the real complexity of felid psychology. We like to talk of the cats (past and present) as “the ultimate killing machines”, but machines they are not. What they are is, just like us, natural born LEARNERS. Cat species are the result of millions of years of evolution, but each individual cat is the result of a long period of dependence, spent learning from its mother. I count myself fortunate to have watched a leopard killing its prey, but I tell you until you watch a leopard mother playing with its cubs you don’t have an idea what it means to be a big cat. I have to admit that I have not paid enough attention to that aspect of cat behavior in my reconstructions of sabertooths, which is all the worse when you consider that there is a fascinating fossil record of the development of cubs in several sabertooth species. More importantly, that record shows us that given the rate and timing of tooth eruption, sabertooth cubs would have dependend on their mothers for food for a very long period of time, long even for a carnivore. Sabertooths were efficient predators sure enough, but just as surely we can say something else: female sabertooths were especially patient mothers. All kittens are a handful, but imagine having one or several growing sabertooths under your care for more than two years… that must have been a motherhood test!
Here are a few pictures (taken by my son Miguel) of some of the big cat families we met in our trip. First, a very succesful cheetah mother who had reared 3 cubs to full adult size (the mother is the one wearing the collar)
The next picture shows just a part of a large lion pride which had cubs of two different ages
And here is one of the leopard families we met, only one cub but enough to keep mom busy…
And finally here is a very old sketch of a Smilodon fatalis family with two equally playful generations of cubs. The fossil site of Rancho la Brea in California includes a rich record of cubs in many different stages of development. I ended up making a painting from this concept, but it was a very simplified version.
During the Miocene, North America was home to an impressive array of sabertoothed predators. Some of them belonged to the Barbourofelidae, a family of carnivores that developed extreme sabertooth adaptations and became extinct during the late Miocene; others were true sabertoothed cats, members of the family Felidae.
Among the latter, there were several species that look superficially very similar to one another, and paleontologists have a hard time trying to sort out their relationships. Were all these species part of a single, native American lineage spanning much of the Miocene period? or perhaps some of them arrived to North America from the Old World as part of succesive immigration events?
This may sound like a very technical issue, but it touches the very core subject of sabertooth evolution: we know that the sabertooth morphology is an adaptation for a very specific killing technique, but, how much of that morphology is the result of shared ancestry and how much is the result of convergence?
After this somewhat technical introduction, let me introduce to you an amazing sabertooth cat: Machairodus catocopis. This predator had the approximate size and body proportions of a modern tiger, but it was armed with elongated, laterally flattened upper canine teeth with coarsely serrated margins that allowed it to kill large prey almost instantly through massive blood loss. It also had a huge “dewclaw” that it used for literally hooking its prey.
Years after its original description, this species was removed from the genus Machairodus and assigned to Nimravides, a change that reflected the belief that it was part of a native lineage of cats that had evolved in North America for many milions of years. Those changes in classification had been made on the basis of fragmentary fossils, but several years ago at the American Museum of Natural History (New York) collections I came across a couple of undescribed specimens that were amazingly well preserved, and they seemed to me strikingly similar to the fossils of Machairodus aphanistus that we were finding in the fossil sites of Cerro Batallones, in Spain.
Now in collaboration with my colleagues Manuel Salesa and Gema Siliceo from the Museo Nacional de Ciencias Naturales (CSIC) I have finally been able to look in detail at the anatomy of those wonderful American fossils, and we have found that the similarities with the Spanish specimens go very deep indeed. This study, now published in the Journal of Vertebrate Paleontology, clearly indicates that Edward Drinker Cope (back in 1887!) was right from the start to classify this animal in the genus Machairodus: it is so closely related to the Batallones sabertooth that if we found its fossils in a Spanish site we would consider it just a slightly more advanced form of the same group. The geological ages of the two populations are consistent with the possibility that the ancestors of M. catocopis arrived to North America as part of a migration wave from the Old World. The original migrant must have been almost identical to the Batallones cat: an immensely powerful animal that had the potential to invade continents and rule as top predator thanks to the combination of a versatile feline body plan and a pair of precociously specialized scimitar-like canines.
By the way, don’t bother to look for Machairodus catocopis in my upcoming book “Sabertooth”. The book went into press before our new paper was published, so I had to stick to the previous classification and call it “Nimravides catocopis”…
Here is the title of our new pubication:
Antón, M, M. J. Salesa and G. Siliceo 2013. Machairodont adaptations and affinities of the
Holarctic late Miocene homotherin Machairodus (Mammalia, Carnivora, Felidae): the case of Machairodus catocopis Cope, 1887. Journal of Vertebrate Paleontology 33:5, 1202-1213
You can check it in the JVP page:
Making a lot of quick sketches is an excellent way for you to absorb the shape and structure of animals. Doing it fast enhances your concentration and makes your brain feel that what you are doing has “survival value” and you switch to deep learning mode.
But as a paleoartist you will want to give things a further, more analytical turn. Once you have captured the shape of the animal you are sketching, it is a useful exercise to try and identify the “bone points”, those spots of the animal’s body where the bone comes so close to the skin that you would feel it if you could touch the animal. Once you have located those points, you can draw a quick sketch of the whole skeleton inside the outline of the living animal. I have done this exercise many times, and it makes you ever more familiar with the way soft tissue is arranged around the bony frame. I cannot overemphasize the importance of this concept in order to reconstruct extinct animals from the inside out!
Now here is an example: three steps in the making of a quick sketch of a galloping lioness, and finally an outline drawing of the same animal with the inferred position of the bones inside.
And here is a schematic representation of the “bone points” in a jaguar.
Go get your pencils and practice, it is useful -and a lot of fun!
What is the most important difference between drawing a modern animal and a prehistoric one? For me, the key fact here is that, with living animals, we can always check our artwork against the real thing and see if we have got the proportions and the “gestalt” of the creature right. But with the extinct species, what is left of their “personality” is determined by their skeletons (the only preserved part in most instances), so that in this case we need to be extremely careful that our drawings are faithful to the morphological information transmitted by the bones.
This is where technology can be especially helpful for the artist. I have found it enormously useful to be able to create accurate, computer 3D models of the skeletons of extinct animals, which then I can render from any angle in order to check how the animal would look in views different from the more classic side view. Such a 3D model will take many hours of work but for creatures that you expect to draw many times it is a worthwhile effort indeed. Of course, the models become even more useful if we animate them, giving shape to our hypotheses about locomotion. Fortunately I have had the help of amazing 3D animators for setting the vanished creatures back in motion!
Here is a couple of renders of my computer 3D model of the skeleton of Promegantereon, and a reconstruction of the animal´s head based on that model:
Now I have uploaded a short clip from the upcoming documentary “Bringing the Sabertooths Back to life” where this subject is mentioned, as well as the following steps of anatomical reconstruction “from the inside out”.
You can check the clip following this link:
I hope you enjoy it!
Now that all the filming for “Bringing the Sabertooths back to Life” is finished, we are busy with postproduction and editing. The film will be ready in a few weeks, but in the meantime I have uploaded a short clip for you to have a glimpse of a part of the complex process of reconstruction.
Participants in our Botswana art safari will be the very first people to see the finished film, which then is expected to premiere at Los Angeles in early Novemeber. I will keep you posted on any new developments.
And here is the link to watch the clip:
The spectacular fangs of sabertooth cats have been often seen as possible adaptations to pierce the hide of giant, thick-skinned prey such as proboscideans. But living elephants are such formidable creatures that it is difficult to accept that they would be the main targets of any mammalian predator. And yet there are pieces of evidence which clearly show that, at least in some instances, sabertooths did hunt proboscideans.
At Friesenhahn cave in Texas ( a fossil deposit of late Pleistocene age) the bones of several sabertooths of the genus Homotherium, including individuals of different ages, were found in association with those of many mammoths and mastodons. The place was in all likelihood used as a den by the cats, and the proboscidean bones show clear tooth marks, proof that the sabertooths were eating from them at the site. The proboscidean bones corresponded to animals between 2 and 4 years of age, a time when they are still of “manageable” size for the predators, but less closely vigilated by the mothers who need to concentrate in protecting their younger, more vulnerable calves.
But even at such young age, elephants make rather inconvenient prey. Even with the long and flattened canines of Homotherium, the diameter of the elephant neck is just too big and the skin too thick for an efficient killing bite to take place, so the dispatching of prey is by necessity long as it gets slowly weakened through blood loss from relatively superficial wounds. On the other hand, the sheer size and strenght of even a calf of this age makes it very difficult for a single cat to keep it pinned down to the ground. This disadvantage is made more serious by the fact that Homotherium, unlike other sabertooths, had long forelimbs with narrow wrists and small, not fully retractable claws (except for the enormous dewclaw).
The scene below shows a group of Homotherium and a young mammoth in the early Pleistocene of Southern Spain.
So, if we look at the overall anatomy of Homotherium we see that it was not an ideally built “elephant killing machine”. In terms of the ability to single-handedly wrestle down a large prey, even a lion is better equipped, but then the sharp canines of Homotherium were a real advantage to inflict nasty, debilitating wounds.
For me, there are 2 conclusions to be gained from this overview of the evidence:
First, that in order to bring down young proboscideans as the Friensenhahn cave sabertooths obviously did, hunting in a group would be a distinct advantage, and in fact it was probably a necessary condition.
Second, that since the overall body build of Homotherium was not that of a “giant slayer”, the odds are that the systematic elephant predation we see at Friesenhahn was either a local phenomenon, or a seasonal one, or both. Elsewhere and at different times of the year, there was probably a variety of prey for Homotherium to take, but my guess would be that it most often concentrated on ungulates of horse to bison size, and whenever it had to hunt individually, it would certainly go for lighter animals like horses or antelope.
So, giant slayer? potentially yes, but only under the right circumstances.
To learn more, look for the book “Sabertooth” in late october!
As the “World Lion Day” approaches, I feel like indulging in a little philosophical reflection… please bear with me, I promise to be brief!
I take it for granted that followers of this blog share my passion for the big, wild carnivores. But I know that for some people this passion might at times seem strange. And yet our preference is a time-honored one: shamans around the world have chosen the big cats as their totem animals and as guides for exploring the world of the unknown, and the fact that one of the oldest known Paleolithic sculptures features a lion-headed man indicates that such an affinity is deeply rooted.
With the sabertooths being my own “totem beasts” since childhood, I have had plenty of opportunity to wonder, WHY this fascination? I suppose that the ultimate cause must remain a mystery. But my encounters with the modern big carnivores in the wild have given me some food for thought.
My first encounter with a wild apex predator took place well over a quarter of a century ago. I was alone, on foot and unarmed, but there was nothing to fear: it was “only” a wolf; a magnificent Iberian wolf, trotting effortlessly –almost gliding- in the early morning light, among the broom and heather of the remote mountains of Asturias, in Northern Spain. The animal was impressive enough, but looking back I find that the impression it made was inseparable from that of the place. Those mountains became magical for me, as any place that can still sustain its top predators must be.
The magic mountains of the wolf, Asturias, Northern Spain. I took this picture in 1997.
Years later I travelled to the African wilderness in search of the big cats, and the same thing happened: the places where I encountered the big cats became magical, strikingly attractive places for me. The lion may be king of the beasts, but what is a king without a kingdom? Conversely, a landscape depleted of its wildlife may be pretty, but a place where the big predators still rule is far more than pretty: it is a place where the laws of nature are fully at work.
Lions in Samburu National Park, Kenya, 2006.
Similarly, the fascination I felt as a child admiring the illustrations of sabertooths by Rudolph Zallinger had much to do with the way the artist had immersed the beasts in their long lost world. Posing dramatically as it stabbed a mammoth trapped in the tar pits, the sabertooth Smilodon seemed the unquestionable ruler of its legendary kingdom.
Well, I think that our admiration for the big carnivores embodies one of our most basic contradictions. On one hand, we humans somehow feel that nature has to be respected if we want it to keep nurturing us, and the big predators are a sort of guardians and living signs of a balanced system. But as members of human society we also perceive that it is other people who provide or deny what we need, making the balances of Nature seem almost irrelevant. In traditional societies shamans were the intermediaries between “ordinary” people, too immersed in their daily affairs, and the mysterious world of non-human nature. Today, the role of the shamans is mostly lost, but it could not be more necessary. Somebody has to transmit the message of the rulers of the other kingdom -the wild kingdom. Lions, wolves, and from their long lost past, sabertooths, all send the same message to us: “We predators have long ruled the wild Earth while abiding the rules of nature. Under our rule, landscapes remain fertile. Under YOUR rule, nothing lasts long”.
A lost Eden: the environment and fauna in the Lake Turkana Area (Kenya) in the early Pleistocene, with the sabertooth Homotherium as the temporary “King of the Beasts” -the proboscideans permitting!
The combination of old fossils and new technologies is taking us closer and closer to understanding the adaptations of extinct animals, and in particular of sabertooths. One recent piece of research by Stephen Wroe and colleagues takes the fossils of the marsupial sabertooth Thylacosmilus from the collections of the Chicago Field Museum, and uses 3D scanning and FEA analyses to compare it with the more “familiar” felid sabertooth cat Smilodon. The Field Museum Thylacosmilus sample was recovered by the 1926 Marshall Field Expedition to Argentina, and it served paleontologist Elmer Riggs to publish an excellent description of the species in 1934. Many decades later, it remains the best and most complete sample of the species, and it was rightly chosen for this “rocket-science” study (you can see the paper following this link: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0066888 ).
The results of this comparison reassuringly confirm something that more conventional studies of the marsupial sabertooth fossils already indicated: that this animal not only had converged with placental sabertooths from its isolation in Cenozoic South America, but it had in fact taken the adaptations for a sabertooth way of hunting several steps beyond what we see in the true sabertooth cats like Smilodon. Sabertoothed predators had a different kind of killing bite than modern cats, so that when jaws were open at full gape and jaw-closing muscles were too stretched to pull with force, it was the muscles of the neck that came into action, pulling the whole head down to help sink the fangs into the flesh of prey. As my illustration here shows, the neck vertebrae of Thylacosmilus were very large with huge processes for muscle insertion, making it quite adequate for such a function.
The new study shows that the skull of Thylacosmilus was well designed to stand the stresses caused by that kind of motion –pulling down the head to sink the canines – and less well prepared to deal with the stresses that would be generated if the canines had to pierce the flesh using mostly the forces generated by the jaw musculature (as it does in modern cats).
The authors conclude from their comparisons that the action of neck muscles was even more important in Thylacosmilus than it was in Smilodon, something that seems pretty evident from the results. But they go one step further and argue that the lower canines did not play any major part in the killing bite in Thylacosmilus. If that were the case, the mandible would still have its role in biting off meat from carcasses and slicing it with the premolars and molars, but it would hardly contribute to the actual killing of prey… may that be true?
Well, most sabertoothed predators have something in common: the area where the two halves of the mandible join under the incisor teeth, technically called the symphysis, is more vertical than in other predatory mammals, and it tends to develop vertical ridges along its antero-lateral edges. In some sabertooths, including Thylacosmilus, this shape is exaggerated and a downward, scabbard-like projection is created. In others, like Smilodon, the projection is nearly absent, but the shape of the symphysis remains unmistakably “sabertoothy”. It is tempting to see the projection as a sort of “protection” for the sabers, but in fact it is more likely related with the kind of forces that the symphysis has to withstand during the killing bite. In “normal” cats, those forces have a large lateral component, but in sabertooths vertical forces were overwhelmingly dominant, and that has likey shaped the anterior part of their mandibles. Paleontologist Bill Akersten in his elegant 1985 hypothesis of the ”Canine Shear-Bite” gave the lower canines and incisors a role in the killing bite, a role that at least partly accounted for the unmistakable shape of the sabertooth symphysis. While there are some studies of the form and function of the mandible in sabertooths out there, more analyses are clearly necessary. But as long as a sabertooth mammal retains a vertical, reinforced symphysis (as is the case in both Smilodon and Thylacosmilus in spite of the obvious differences), we have good reason to think that the mandible had an important role to play in the killing bite.
If you are interested to read more about this, look for the book “Sabertooth” in late October!
Here are a couple of references:
Akersten, W. A. 1985. Canine function in Smilodon (Mammalia; Felidae; Machairodontinae). Contributions in Science 356: 1-22.
Riggs, E.C. 1934: A new marsupial saber-tooth from the Pliocene of Argentina and its relationships to other South American predacious marsupials. Transactions of the American Philosophical Society 24, 1–32.