Monthly Archives: February 2015

Fangs for show?: making sense of Megantereon’s toothy grimace

For more than a century paleontologists have been puzzling about the function of the sabertooths’ namesake upper canines, with new studies and analyses being published every year, and a sort of consensus is emerging about the way these extinct predators would use their impressive weaponry, as discussed elsewhere in this blog. But a few decades ago it was fashionable to say that such enormous canines could not be used for killing prey and were there only for display. According to that view, sabertooths would intimidate other predators with their showy fangs at kill sites and gain access to carrion, (their primary food source, according to such theories) as well as using them to resolve disputes with rival males for the access to females.
There are many reasons why this theory is wrong, as I discuss at lenght in my book, “Sabertooth”. But the important thing I would like to stress now is that, although the primary function of the “sabers” was related to hunting, it doesn´t mean they weren´t used in display. For instance, let us look at Megantereon. When the animal was relaxed, the tips of the upper canines would protrude beyond the upper lips, an impressive but not neccesarily scary sight.

Here is a protrait of a relaxed Megantereon with the tips of the sabers protruding beyond the lips
megantereon relaxed

But when several muscles of the face contracted, pulling back the lips and moving up the nerve pads of the whiskers, the resulting display of teeth would give pause to any rival. However, the facial language of the sabertooths, like that of any cat, would be more complex and subtle than just an option between baring the teeth or not. Felids share with us primates the privilege of having more facial muscles than any other mammal, and they can convey a wide range of emotions to a conspecific with their facial expressions. Baring the teeth more or less fully, opening or closing the eyes (and pupiles), turning the ears one way or the other, all these elements combine to send totally different messages. For instance, in the illustration shown here Megantereon is not really trying to intimidate anyone; instead, it has just caught the smell of another cat in the plants around it, and is performing the “Flehmen”, a non-aggressive gesture that is produced as the animal tries to smell particles in the air with the Jacobson’s organ, located in its palate.

This illustration shows Megantereon as it bares its teeth during the Flehmen gesture
megantereon snarling

Facial expression is completed with motion. It can be sometimes difficult to read the difference between a Flehmen gesture and an aggresive snarl in a still photograph, but in the live animal there would be no possible confussion. When doing “flehmen”, the cat moves its head slowly to the sides as it tries to capture the scents in the air, but I don’t need to remind any cat owner of what kind of motions and gestures accompany the baring of the teeth in an irritated feline!
But let us not deceive ourselves, even when the teeth are used “for show” in aggresive displays, the animal must be ready to turn threats into real aggression. And that was a definitive weakness of the “display only” theory of sabertooth canine function. If paleontologists rule out the use of the sabers in hunting because of their supposed fragility, then it makes little sense to hypothesize that they were used to scare rivals away, because no display of strength can be used indefinitely without an occasional demonstration. And biting your rivals during a fight is no less dangerous for fragile teeth than it is to bite your prey. In fact, during a dirty fight with a rival cat there is even less control and more chance for breakage.
Sabers were there for show, most certainly. But not merely!

Was this the most extreme sabertooth ever?

The American Pleistocene genus Smilodon is probably the most famous sabertooth, and it certainly was the largest, and one of the most spectacular. It also was the last of its lineage, only becoming extinct after modern humans reached the Americas. But, was it the most extreme form of sabertooth ever to exist? Well, in terms of the anatomical adaptations for the sabertooth hunting and killing method, I think it wasn´t.

I would propose several candidates for the title of the most extreme sabertooth, including species of the genera Thylacosmilus (a metatherian), Eumilus (a nimravid) and Barbourofelis (a barbourofelid). Among these, Barbourofelis fricki, from the late Miocene of North America, combines large body size (although certainly smaller than Smilodon) with proportionally huge upper canines, together with a skull that has undergone a more radical transformation than that of any placental sabertooth, and body proportions that reflect enormous muscular power and the ability to wrestle down large prey and keep it completely immobilized while the predator executed its very specialized and precise killing bite.

Here you can see several preliminary sketches and the finished reconstruction of the head of Barbourolefis fricki. It took me several attempts to choose the angle of view and the lighting which best showed the unique porportions of this animal’s head
barbourofelis head collage baja b

Here is a full body reconstruction of Barbourofelis fricki. Notice its stocky proportions, with short and extremely muscular limbs
Barbourofelis fricki full body 2015

If you think that other sabertooths were more specialized you could be right at least in part, because the skull of Thylacosmilus, with its ever-growing sabers,was even more weird-looking, while Smilodon populator had the most massive sabres ever and would have taken the lergest prey of any sabertooth in the whole Cenozoic. But in terms of the total set of adaptations that it displayed, Barbourofelis fricki certainly pushed the envelope, and if we could see it in action we would witness the ultimate lesson in sabertooth hunting style. Frustratingly, we will have to rely on our studies of functional anatomy to have any idea of how these amazing predators dealt with their prey. But learning more and more about them is also a lot of fun!

If you want to know much more about these creatures, check my award-winning book “Sabertooth”!

“El gato”: getting familiar with the Iberian Lynx

Naturalists who study the Iberian lynx often call it simply “el gato” (“the cat”). At first it surprised me to hear it called that way, and it even sounded a bit like it took the mistery away from such an impressive creature. But as you spend more time observing the lynx behaving naturally in its habitat it strikes you how similar it is to your house cat in so many of its gestures and reactions.
In 2013 we observed this male lynx courting a beautiful female which was not yet ready for mating and made its rejection perfectly clear. After walking around her for a while he just sat and looked away with that expression all cat owners have seen, and which seems to say: “what should I do next? Most definitely, not hurry. It would be indignant for a cat to appear to be in a hurry!”

I tried to quickly capture the essence of that moment with my pencil. As always, I try to define the general shapes in 5 minutes or so. It is especially important to focus your attention on the general masses of the head, shoulders and legs rather than being distracted by coat patterns. The markings of the iberian lynx are so striking that it takes some concentration to perceive the animal´s real volumes underneath.
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Once the main features seem to fit, it is time to add some shading and detail.
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Leave most of the spots for the end! You will be glad you refrained from putting the markings in place before the cat’s actual shape.
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It takes time to get familiar with the shape of this very special cat. I will be exploring some less obvious aspects of its structure and natural history in upcoming posts. Stay tuned!

The Prince of Spanish Oligocene predators: Dinailurictis

Most members of the extinct family Nimravidae were cat-like predators from lynx to leopard size, including the famous sabertoothed genera Eusmilus and Hoplophoneus. But in the European Oligocene some nimravid species (more closely related to Nimravus) evolved to fill the niche of the superpredator, reaching the size of a modern lion. One such monster was Dinailurictis, whose fossils have been found in the Spanish Oligocene site of Carrascosa. Most herbivores living in the Europan archipielago at that time were pretty smallish creatures, and you would expect that for much of the time Dinailurictis was actually catching prey smaller than itself.
With a body mass of around 130 kg, Dinailurictis was one of the largest nimravids ever to exist, but in Carrascosa the remains of an even larger relative have been found, and classified as Quercylurus. These animals would rival a male lion in mass, with a weight of about 200 kg! Quercylurus would thus be the king of Spanish Oligocene predators and the biggest nimravid ever, but its remains are quite fragmentary and the differences with Dinailurictis rather subtle, so more material would be most welcome to make a clearer case for the presence of two species of giant nimravid in Carrascosa.

Now here is a reconstruction of Dinailurictis based on the Carrascosa fossils and on remains of related animals. The predator has just caught a vaguely pig-like ungulate of the genus Methriotherium, while in the background two minute herbivores of the genus Cainotherium warily leave the area.
carrascosa fragment low res

This is just a corner of a larger scene depicting the strange fauna of the Oligocene in the plains of Central Spain. More to come!

A Close Look at the Iberian Lynx

The Iberian lynx is a creature of superlatives. It is the largest cat species in Spain and arguably the most beautiful, and certainly the most endangered cat species in the world. Just a few years ago it was within an inch of extinction, and many of us feared there was no real hope for it. Now it is clearly making a comeback, but there is an urgent need of renewed efforts for its conservation. The rabbit populations in key lynx habitats are suffering from devastating diseases, and not enough is being done to restore them, leaving the cat struggling for food. Meanwhile, too many lynxes are being hit by cars in roads which should have long been adapted to the presence of the cat; and of the few individuals that have been released in selected places of their former distribution areas, too many are being killed by illegal “vermin” control activities. The lynx has shown it has the potential to regain its place in the Iberian wilderness, so it is our turn to show we can do our part of the deal.
Just like the African big cats (and after generations of not being shot on sight like vermin), the Iberian lynx shows a royal indifference to human observers. Such behaviour may allow excellent observation once you are lucky enough to come across the cat.
One such encounter earlier this year gave me an unprecedented look at this amazing predator. And perhaps the most incredible thing is the look in its eyes. I am always amazed at the look of lions, leopards and cheetahs, but the eyes of the lynx look almost too big, too intense. As the animal sits or walks in front of you, its gaze is almost always directed elsewhere, but if it crosses your own for a second, I promise it will give you the goosebumps! To capture its essence with your pencil is a very special challenge.

As always, I try to get the general proportions of the animal with a few pencil strokes, spending no more than a few minutes
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In this case, much of the face is shadowed, so it is important to play with different shades of grey to imply shape and mass
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Finally, hair texture and the spot pattern hopefully will bring the animal to life in your page!
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There is more to come about the Iberian lynx, an animal full of mystery and beauty!

“Let’s Play”: Sketching a young Okavango Cheetah

Seeing small leopard or cheetah cubs at play reminds us of children in many ways, but adolescent cats may seem deceivingly mature… until their behaviour betrays their age. In the 2013 edition of “Drawing the Big Cats” we came across what seemed to be 4 adult cheetahs. Could this be a powerful coalition of males patrolling their patch of the Okavango? As a matter of fact, as soon as we came close enough to appreciate details, we noticed the longish hairs on the napes of three of the cheetahs, a clear sign of their immature status. And once you start looking at their demenour you soon notice subtle and not so subtle signs of youth. Mother cheetah, resting on a nearby shade, looked patiently at her children, which had full bellies that clearly called for a catnap. But even as they laid down to digest their recent meal, their eyes showed a longing for play. I was especially captivated by the playful attitude and mischievous look of one adolescent cat, which became the subject of this afternoon’s sketching session!

I especially enjoy the challenge of drawing three-quarter views of cats, which create a sense of depth and solidity. It is best to capture those three-dimensional shapes in the first couple of minutes, so that afterwards you need not worry about proportions…
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With the basic shapes in place, you can focus on those shades and contours that best define structure and mass
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Finally it is time to deal with hair texture and spots, but taking care not to obscure the main shapes that you had defined previously
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It is a bit as if by sketching the cheetah all those months afterwards, I am responding to the invitation implicit in the look of its youthful eyes: “Let’s play!”