Spying on the big cats: an ancestral occupation

Prey animals are often quite interested in their predators. If you have spent time in the African wilderness you may have seen how the antelopes seem to shadow a leopard that ventures out from cover. The herbivores apparently consider that the most dangerous predator is the one that you can’t see, so they always try to keep the big cats in sight.
For our own ancestors, curiosity about the predators was a more complex thing. The very earliest hominins were almost exclusively vegetarian so they fit the role of potential prey very well. Fascination for the big cats equaled fascination with danger, a danger you need to know in order to better avoid it.
But, just as modern chimpanzees now and then include some monkey in their diet, australopithecines were likely to have more than a passing interest in meat, and from that point on, the felids became even more interesting, as examples of an extremely efficient fellow predator.

Somewhere in a humid forest in Southern Africa, a hominid of the species Australopithecus africanus spies on a melanic specimen of the “false sabertooth” Dinofelis barlowi, feasting on its kudu kill
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Then another big change happened in our hominin ancestors’ behavior. Not content with an ocassional taste of meat, they became regular scavengers, a development inseparable from their ability to shape the kind of stone tools that allowed them to deflesh and break the bones of animals. From that point on, sabertooth cats and other big predators became potential providers of fresh carcasses, and hominins needed to become ever more acquainted with the details of their behavior, not only in order to predict when and where to look for their kills, but also to avoid becoming new kills themselves during the process of stealing.

Perhaps it is not surprising that when modern humans developed the ability to create art, the first subject they turned their attention to were the big cats. Learning about the felines was a way to know nature (and human nature) in more depth. To this day, drawing the big cats is an unsurpassed way to grasp the secrets of what it means to be alive in this world. I for one never tire of it, and it is good to know that my passion has such a long pedigree. If I am a freak, at least I am in good company!

Reconstructing a monster bear

Several years ago I was approached by the BBC and asked to produce an accurate reconstruction of the giant short-faced bear, Arctodus simus, to be used by a team of 3D artists in order to create life-like animations of the animal. I had drawn Arctodus before but this project required a more in-depth approach, so I set to review all the available information about the anatomy and body proportions of this amazing ursid.
I consulted with paleontologist Paul Mattheus from the university of Alaska in Fairbanks who sent me his Phd thesis along with a wealth of data about the giant bear. With all those figures and measurements I put together a detailed reconstruction of the beast’s skeleton, based mostly on the nearly complete specimen from Fulton County in Indiana, but complemented with bits from other findings. One especially nice skull from Alaska allowed me a detailed restoration of the animal´s head.

In this collage you can see my drawings for the reconstruction of Arctodus simus, from a working sketch of the skeleton to a restoration of the animal’s musculature and soft-tissue outline and a detailed rendering of the head
arctodus-reconstruction-collage-1-low-res

The creature that emerged from those drawings was quite impressive. With especially long limb bones, it attained a shoulder height of 1.75 meters -while standing on all fours the animal’s eyes would be level to yours! The reconstructed head had a short face indeed, but on top of that the head looked relatively small for the animal’s massive body. Seen from the front, Arctodus also looked tall, narrow and small-headed relative to a modern brown bear.
The next step was to set the animal in motion. The relatively long limbs of Arctodus led some paleontologists to infer that it would be a good sprinter, a very active predator catching speedy prey on the run. But Mattheus’ analysis of the giant bear’s anatomy led him to a different conclusion: Arctodus would move around at moderate speeds with an efficient pace, with more endurance than speed, which in his view was an adaptation for covering huge distances in search of carrion that it would then appropriate using its huge bulk to expel other predators. In other words, the giant short-faced bear would have been a kleptoparasite. Even its great stature when standing on its hind legs would allow it to scan the horizon for any sign of a recent kill.

This second batch of sketches shows the pacing walk of Arctodus and the bipedal posture it would adopt now and then to scan its surroundings. Finally there is a full-color rendering of the living animal
arctodus-reconstruction-collage-2-low-res

Was that the real ecological niche of Arctodus? Well, if the dentition of an animal is our main guide to inferring its diet, then Arctodus was not a specialized scavenger, for one thing it didn´t nearly have the refined adaptations of a hyena for cracking bones. The teeth of Arctodus were, in spite of differences in detail, bear teeth, and that means a broad-spectrum diet. It could certainly steal kills from most predators around it, but it could also consume vegetable matter and kill its own prey now and then. Its wide distribution in North America indicates a considerable habitat tolerance, and probably a high degree of adaptability, but not enough to survive the wholesale extinction of large mammals at the end of the Pleistocene. As a result, now we need to resort to paleobiological reconstruction if we want to have a reasonable idea of what it looked like and how it behaved. Sad, but better than nothing!

Weird and Wonderful: Reconstructing Synthetoceras

Browsing old folders I came across a series of sketches I did several years ago during the preparation of my illustrations for the American Museum of Natural History exhibition “Extreme Mammals”. Among them there was a sequence of drawings showing the process of reconstruction of the American Miocene artiodactyl Synthetoceras tricornatus. I had painted this species before but in this assignment the animal would be shown in full detail so I wanted to double check all my information. One of the best sources was the sample from the fossil site of Love Bone Bed in Florida, and it served me as a reference to bring the animal back to life. I started by drawing all the known bones to scale in order to get an accurate representation of body proportions. I drew missing parts of the skeleton using a more completely known relative, Protoceras, as a model.

Here are the first stages of the reconstruction of Synthetoceras, starting with the assembling of the bones all drawn to scale according to published measurements, and continuing with soft tissue outline and external appearance.
1-synthetoceras-reconstruction-first-batch

Once the skeleton was assembled, I could proceed to draw the sof tissue outline of the living animal in side view, which gave me a clear idea of its proportions. With a shoulder height of nearly 90 cm, the animal was not especially impressive, and couldn´t rival a modern red deer, for instance, in linear dimensions. But its robust, stocky bones supported a heavy body and a male like the one depicted in this reconstruction could weight around 200 Kg.

The bizarre head appendages, sported only by the males, are the most characteristic feature of this species, and it was essential to depict them correctly. In order to give them depth and realism I needed to make sure that the shading was right, and to that end I sculpted a small clay model of the head, which I put under the kind of light I wanted to use for my reconstruction.

A side view is one of the most informative ways to depict an extinct mammal, but exhibit designers wanted something more dramatic in order to engage the public, so they asked me to show the walking animal in perspective, as shown in one of my preliminary drawings. But this was not judged engaging enough and they asked me to show the animal galloping.

Here is a second batch of images showing the clay model of the Synthetoceras skull and the various drawings that incorporate the lighting based on it. The animal was first shown walking but finally a more dynamic pose was chosen.
1-synthetoceras-reconstruction-second-batch

The final step in the reconstruction was to create a hypothetical coat color pattern. Again, the exhibit designers wanted something dramatic, so I borrowed patterns from a diversity of modern ruminants in order to create something that had a lively contrast but remained biologically sensible.

synthetoceras-color

A Glimpse into an Eocene Lost world

Isn´t it amazing to think that 35 million years ago, long before the sabertooth cats (or any true cat for that matter) ever evolved, there was such a specialized sabertoothed carnivore as Hoplophoneus mentalis?. This creature was about the size of a large lynx but it specialized in taking prey larger than itself, which it killed by a devastatingly efficient bite to the throat. But rhino-sized animals like Megacerops, shown in the background, had nothing to fear from this cat-like predator.

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OLYMPUS DIGITAL CAMERA

At a first glance (and even at a second and third) the skull of Hoplophoneus mentalis is so similar to that of true sabertooth cats like Megantereon, which lived more than 30 million years later, that you would be excused for taking it for a real cat, even for a direct ancestor of such younger species. In fact, the best heads of paleontology were such deceived for many decades until the detailed study of obscure anatomical features, such as the structure of the ear region of the skull, revealed the true affinities of those cat-like carnivores, which are now classified in an independent family: the Nimravidae.
hoplophoneus-mentalis-head

The late Eocene of North America, nimravids included, is one of the most amazing “Lost Worlds” discovered by paleontology. Read more about it in my book “Sabertooth”!

The 4-dimensional safari

Looking back at four years of our “Drawing the Big Cats” safari I am amazed at how much I have learned first-hand about the cats and their adaptations to their wild home -and I thought I knew something! That experience becomes a key ingredient to enrich my renderings of the felines, and my reconstructions of their fossil relatives and their lost world, not to mention the challenge to try and reflect those complexities with my limited abilities… But beyond those “practical” applications, I also get the impression that my life has grown in several dimensions: length, width, depth, height… and I suspect I am not alone in feeling that way!
Length, because each minute in the wilderness of Botswana seems to last so much more than it would do on an average day back at home. Our life lengthens each time we go there!
Width, because the endless horizons of the African savanna seem to create new room within the soul, to make our mind more spacious and free to roam wherever it will.
Depth, because the myriad sensations, both striking and subtle, that surround us while on safari, (especially when camping out in the bush), renew our senses and give us an intuition of a world where boredom is impossible and whose deep complexity we could not begin to comprehend in a lifetime.
And height, because there we are given a privilege of a true spiritual kind. Flying over the Okavango delta we know we are witnessing a miracle, not only because this giant oasis in the Kalahari sands is such an improbable phenomenon, but also because its preservation is a monument to the faith of many women and men who have fought hard to preserve this jewel for all of us. I get a renewed sense of awe both at wildlife and at that particular breed of people who can recognize what gives our life dignity, what makes us truly human, and are ready to devote themselves to protect it in a brave and selfless way.

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After each trip we come back home with a treasure of memories, pictures, sketches… but perhaps the most important thing is less easy to define: we could call it a transformation. While out in the wild, we are reminded of (and submerged in) the things that matter in life: nature, art, good company. And we become more able to free ourselves from the many petty traps that ensnare us in everyday life. If I picture myself back in Savuti, looking up at the star-filled sky after the campfire is no more than cooling embers, then, strangely enough, everyday problems appear more manageable. Have you felt the same way? Well, no magic tricks here, just pure life force of a kind we can only get in the place that made us human: the African savanna, the Cradle of Human Kind. I cannot wait to go back!

Legends of the Flores “Hobbits”

A couple of years ago a TV producer asked me to create a few reconstructions of Homo floresiensis, popularly known as the “hobbit of Flores island” for a documentary film. They wanted the images to be grounded on scientific fact, but quite especially they wanted them to be dramatic and striking.

The first image depicts an imaginary conflict between a band of “hobbits” and several Komodo dragons. The producers asked me to show the very biggest dragons that could exist, in order to remark the contrast with the tiny, 3-feet tall hominins
dragon-scene-low-res

The second image shows the hobbits spending time up in the jungle canopy, in relation with the climbing ability suggested by some details of their osteology
hobbits-in-trees-scene-low-res

Of course it is possible that such “climbing” adapations are just primitive features retained by H. floresiensis from its distant ancestors, but at any rate the right question to ask is probably why would they spend any substantial time up in the branches? Escaping a hungry giant varanid would be one occasional reason, but anatomically modern humans (giants to the hobbits’ eyes), which invaded the island at some point, could be another motivation to seek refuge up in the trees.

The third image shows a band of hobbits hunting one of the dwarf proboscideans that inhabited Flores in the Pleistocene
hobbits-and-stegodon-low-res

Although the elephant-like creatures were very small in comparison with their relatives from the continent, their hunters were similarly tiny, so this lilliputian confrontation implied a considerable risk of injury.

All in all, making this set of illustrations was a very interesting experience. When creating scenes from the distant past I tend to be rather conservative and choose the kind of interactions that are most likely to have taken place. But in this ocassion, the pressure from the client to create more dramatic, risky scenes took me to some exciting new grounds.

Sprint of the giant cheetah

Today the cheetah, Acinonyx jubatus is the only cat with clear adaptations for extremely fast sprint running, but in the past there were other species, more or less closely related to it, which also developed that kind of specialisation. The American cats of the genus Miracinonyx (about which I wrote in some detail in an earlier post) lived during the Pleistocene and paralleled to a remarkable degree the cursorial features of the cheetah skeleton, although none of them was quite as specialised as the true cheetah. But in the Pliocene and Pleistocene of the Old World there was an early species of the true cheetah genus Acinonyx, what we could call a cheetah with a difference. Of course I am talking about Acinonyx pardinensis, the giant cheetah known from many fossil sites from Spain to China, and which is known to have been considerably taller than the modern species. It is tempting to imagine that, having comparable adaptations for running as the modern cheetah but with absolutely longer limbs, the giant cheetah could have reached higher peak speeds, but would it?
Many years ago I had the opportunity to study casts of a partial skeleton of A. pardinensis from Perrier (France) housed at the Paris Museum of Natural History, and I was impressed by the animal’s enormous size and advanced running adaptations. The animal probably weighted about 70 kg, but its limb bones were quite elongated and so were its lumbar vertebrae, betraying a long and flexible back just as in the modern cheetah. But a detailed examination reveals some features in which the giant cheetah appears to be intermediate between the advanced morphology of the modern cheetah and that of the more “normal”, slower cats. For instance, the femur is not as strongly bowed as in A. jubatus, and the fibula is relatively robust without signs of the incipient fusion with the tibia observed in living cheetahs. In the radius, the tuber for the biceps muscle occupies about 10% of the shaft length in A. pardinensis as in most felines, while in the modern cheetah it is only half that long (muscle force tends to concentrate in the proximal part of the limb in the cheetah, as in all cursorial mammals).

Here are some of the limb bones of A. pardinensis that I photographed in Paris
a-pardinensis-limb-bones-paris

And here are some of the animal’s vertebrae
a-pardinensis-vertebrae-paris

In this comparative drawing the skeleton of the modern cheetah, Acinonyx jubatus (foreground) is shown to the same scale as the extinct giant cheetah, Acinonyx pardinensis (background)
a-pardinensis-skel-to-scale-with-a-jubatus

More recently, the bones of the forelimb of a giant cheetah were found at the Georgian site of Dmanisi, and their study has revealed some interesting facts. The authors estimate that the body mass of that individual would be in the vicinity of 100 kilos, quite larger than the individual from France that I examined and more than twice the average weight of extant cheetahs. The humerus bone is far more stout than in modern cheetahs, probably in relation with the animal’s great mass, but otherwise the proportions of the bones are remarkably elongate.

Here is a photo of the Dmanisi giant cheetah forelimb exhibited at the National Museum of Georgia in Tbilisi (by the way, the small round objects are not cheetah bones, they are actually hyena coprolites!)

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OLYMPUS DIGITAL CAMERA

Other fossil sites, including Saint Vallier in France and Pantalla in Italy, have yielded amazing fossil skulls of A. pardinensis, showing a considerable but not total similarity with modern cheetahs. The skull was proportionally somewhat longer and lower than in A. jubatus, thus resembling more “conventional” cats. But the dentition is very similar to that of the modern cheetah, especially in the fact that the upper carnassial was remarkably blade-like, lacking the inner cusp or protocone. This feature indicates that the animal consumed little if any bone, and, just like modern cheetahs, it would hurriedly eat the more meaty parts if its prey and leave the rest for more powerful competitors.

Here we see a life reconstruction of A. pardinensis (background) shown to scale with a modern cheetah
a-pardinensis-compar-low-res

All in all , we get a complex picture of A. pardinensis. Undoubtedly it would be an extremely fast sprint runner, but its adaptations were a little less refined than in its modern relative, which, combined with a greater body mass, almost surely implied that it would not be a faster animal, in spite of its longer legs. Once A. pardinensis made a kill, its blade-like carnassials allowed it to cut and consume skin and meat very efficiently, but it would probably not stay at the kill site long enough to consume any significant proportion of bone. And it makes sense that, in a world populated by large jaguars, sabertooths like Homotherium, giant hyenas like Pachycrocuta and packs of wolves, the elegant giant cheetah would not risk injury in a fight over a carcass. Just as in the modern cheetah, there was a price to pay for extreme sprinting efficiency. And just like its modern relative, its hunting would have been a true spectacle of nature. Ah, to see such a scene!

Here is a reconstruction of A. pardinensis in hot pursuit of the Pleistocene antelope Gazellospira
acinonyx-pardinensis-and-gazellospira

Iberian lynx: the value of the individual

Early this year we had the privilege of encountering this majestic Iberian lynx in the wilderness of southern Spain. A recent study reveals that the genetic diversity of this species is alarmingly low, something that makes each wonderful individual like this one even more valuable (you can check the study here: http://genomebiology.biomedcentral.com/articles/10.1186/s13059-016-1090-1). It is almost a miracle that we still have the Iberian lynx with us, and it is such a shame that so many of them are killed by cars each year (see a recent news article about the latest lynx killed by a car: http://genomebiology.biomedcentral.com/articles/10.1186/s13059-016-1090-1), not to mention those that fall victim to the ridiculous “predator controls” still practiced in many private hunting concessions in Spain. In spite of genetic problems and centuries of persecution, the Iberian lynx has shown it has what it takes to make a comeback: now it is time for the authorities to get serious about protecting each cat.

One thing you learn from trying to reconstruct fossil creatures is to value the everyday wonder of encountering living, breathing animals in their environment. Unlike the case of our reconstructions, there is so much in them that we didn’t put in there! Portraying the individual is something that is usually beyond the scope of paleontological illustration, because fossils only tell us so much about the variation and subtleties of physiognomy. If only by contrast, that makes it even more enjoyable to be able to portray living, unrepeatable creatures like this male Iberian lynx in his prime.

A few pencil strokes are enough to define the broad proportions of this walking lynx
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At this stage, I concentrate on the shading in order to create volume and depth, but I already block in some of the spot patterns of the face. The animal’s shadow on the ground contributes to create the feeling of perspective
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In the next stage of the drawing I gradually add more spots
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I continue adding spots, but as I advance with this process some of the shadows I defined at the beginning are now looking almost too subtle by contrast with the more marked spots,so now I have to deepen them in order to keep the balance between light and dark
lince-camina-4

On the track of Smilodon, at last!

A couple of the earliest posts in this blog were devoted to the scanty record of cat fossil footprints, and in one of them I regretted the absence of any recognizable tracks of Smilodon. That was indeed an important hole in our knowledge because some specialists have long hypothesized that Smilodon would be a plantigrade cat. In fact, several kinds of sabertooh cats had features in their limb anatomy that were interpreted at some point as indicative of a plantigrade posture. Such features were present, for instance, in the skeleton of Homotherium, and back in the 1960s the famous paleontologist Bjorn Kurtén hypothesized that this animal walked on plantigrade hindlimbs. But, what does that really mean in terms of the locomotion an appearance of the living animal? Well, if Homotherium were plantigrade then its rump would be much lower, since the hindlimbs lost a whole segment (the metapodials) in height, and the part of the leg that rested on the ground would be proportionally much longer. The animal’s stride would become much shorter, and its gait, ungainly. One of the clearest ways to show the implications of that hypohesis is to create a detailed skeletal reconstruction of the animal in such a posture and compare it with the digitigrade alternative. I did such an experiment some time ago, and I found the results quite striking.

This illustration from my book “Sabertooth” shows the striking difference between how a digitigrade Homotherium would look (top) compared to a plantigrade one (bottom).
homotherium-digitigrad-plantigrad-low-res

At any rate, other specialists such as R. Ballesio and L. Ginsburg made quite detailed analysis of the functional anatomy of the feet in sabertooths and convincingly argued that Homotherium, and in fact all members of the family Felidae, extinct or extant, were perfectly digitigrade, with the possible exception of the earliest species comprised in he genus Proailurus. My own research in collaboration with paleontologists like Angel Galobart, Alan Turner and Manuel Salesa, added further evidence to confirm the digitigrade stance of Homotherium.
But while there seems to be a growing consensus about the posture of Homotherium, some specialists still think that heavier, shorter-limbed sabertooths such as Smilodon or Xenosmilus would have been plantigrade, and one of their arguments is the sheer mass of these robust animals. Such views imply some degree of confusion between the normal standing or walking posture of an animal and its running abilities. It is an observed fact that many digitigrade carnivores, such as dogs, are fast, lightly built runners, while heavy, robust animals like bears are plantigrade. But this does not imply a real correspondence between build and posture, and one must rememeber that among extant cats the hyper-robust jaguar, for instance, is perfectly digitigrade, just like the agile cheetah is. Whatever the case, we still see skeletal reconstructions that show those extinct cats with a bear-like, plantigrade stance.

The details of the limb osteology of these animals fit better with a digitigrade posture, but finding the creatures’ fossilized footprints would go very far in proving their actual gait and posture. And finally, earlier this year, Argentinan scientists M. Magnussen and D. Boh reported the discovery of two sets of carnivore footprints in a Pleistocene site near the coastal city of Miramar that belong, with all likelihood, to Smilodon populator, the largest and heaviest species of the genus. The tracks are the right age, the right size and the right morphology to correspond to Smilodon, whose fossils miraculously happen to be present in the same locality. And there has never been a cat-like carnivore in South America that even approached the size of Smilodon, so the attribution of the footprints looks pretty safe.

This illustration shows a reconstruction of Smilodon populator shown to scale with one of the recently discovered footprints. The print corresponds to the right forefoot.smilo-populator-con-huella

What about the cat’s gait and posture? The footprints leave no doubt that the animal was digitigrade, just like the much smaller modern jaguar is. The footprints also confirm that the animal’s claws were retracted during the walk, although there is one interesting detail in one of the prints, that corresponds to a forepaw: a small mark on the inner side of the footprint would correspond to the position of the dewclaw, which doesn´t normally touch the ground in modern cats. But, given the remarkably short metapodials of Smilodon combined with the enormous size of its dew claw, it would make sense that it would touch the ground at least occasionally, as it seems to have done in this case. Also, the footprints’ enormous width corresponds well with the immense size of the paws of this predator, whose trail has been finally found, more than a century after its fossils were recognized by paleontologists as those of perhaps the most powerful cat ever to walk the Earth.

Lessons from feline violence

Out in the wild, the big cats spend most of their time just resting, and it is only on rare occasions that one gets a glimpse of their full potential for explosive action. And yet it is those brief moments that their whole structure is designed for. When I sit at my drawing table conceiving an action scene, as in the case of my illustration of two fighting Barbourofelis, I try to get all the details of the action right, and I use my memory and all the reference material available to represent the conflict taking place.

This reconstruction of two Barbourofelis fighting over a kill was an attempt to portray sudden action
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But last summer in Botswana we had a totally unexpected opportunity to see what a big cat fight really looks like. I referred to that episode in a previous post, but there is so much more about those amazing moments. One amazing aspect which unfortunately you cannot show in a painting is sound: the animals are impressively loud, and you don’t just hear the sound, it really gets to your guts. Another important factor is speed (it all happened in less than 5 seconds) but that is also impossible to show in a static image, even if it can be implied. There is a lot of other elements that can indeed be represented through drawing and painting, and they take a good deal of study to comprehend. It is a good thing that we can bring back our pictures and videos in order to elaborate an experience that struck us like lightning and will stay with us while we live.

Here is a picture showing one particular moment of the lioness’ hair-rising charge on the male
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And here is a sketch showing a detail of this same conflict
furious lioness 7

Watch this video showing a few of the many highlights of our trip: