For those who would love a Mammuthus primigenius for Christmas as much as I would, click here!

Sometimes when it looks like a cat and acts like a cat it’s not; it’s a nimravid! Nimravids are a rather problematic group in the order Carnivora of uncertain descent. Entering the fossil record in the late Eocene (36 million years ago), their exact relationship to other carnivore families is unresolved, but they paralleled cats to an amazing degree. With short faces and fully hooded, retractile claws, they came in body shapes and sizes that covered all of the diversity that true cats would later manifest. Some were as small as house cats, while others were the ecological and functional equivalents of lynx, cheetah and leopard. And all except one lone genus were saber-toothed.

Before we go on, let’s get these curved teeth straight. Saber-teeth evolved from normal, conical canine teeth into two forms. Dirk teeth were the long, curved, finely serrated blades that we normally think of when we think saber-toothed. The famous Smilodon - the saber-toothed “tiger” of LaBrea Tar Pits fame - was a dirk-toothed true felid. There were also scimitar-toothed animals with shorter, more coarsely serrated blades that usually evolved in conjunction with longer-legged cursorial body types. Most of the dirk-toothed animals were compact, robust stalkers.

For a closer look at Barbourofelis fricki click here

Barbourofelis fricki was the last of the nimravids, dirk-toothed and huge. Its name, “Barbour’s Cat“, shows just how close and how confusing convergent similarities can be. This was a massive creature, the size of a modern lion, but more heavily built. At rest or when walking, it stood and moved in a plantigrade fashion, rather like a bear. One look at the business end of the animal however, lets you know that Barbourofelis wasn’t looking for berries. It possessed some of the largest saber-teeth of all time, and the body to back them up. Behind the catlike face, the head had a flat profile caused by the expanded occipital region at the back of the skull. This allowed for the attachment of powerful neck and shoulder musculature, the driving force behind the sabers. This was a stalker and killer of large game.

Nimravids have an interesting history in North America. Throughout the Oligocene, they assumed all the predatory roles later taken by true cats. But by the beginning of the Miocene, 23 million years ago, they had all disappeared. For whatever reason, perhaps because there was an abundance of arctoid (doglike) carnivores of all descriptions present here at the time, there were no nimravids in North America for the next few million years. Felids also were missing and made their North American debut in the form of a small conical-toothed animal, Pseudailurus, about 17 million years ago. (Showing up to really confuse things a few million years later was a scimitar-toothed true cat named Nimravides! Got that? “Barbour’s Cat” is a nimravid, and Nimravides is a real cat! Aurgh!!!)

Finally, after a 10 million year absence, nimravids returned, most likely from Asia, in the form of Barbourofelis. They show up as moderate-sized creatures with moderate-sized dirk teeth.

For a closer look at Hipparion’s very bad day click here

This is an early barbourofelid species based on California material attacking the three-toed horse Hipparion. It is also one of my very first digital paintings. It was done a few years ago for an article by Joe Eaton in the September, 2001 issue of Bay Nature, a Northern California publication dedicated to all aspects of San Francisco Bay Area natural history. Getting this image ready for Olduvai - and I did work on it - I was amazed at how much I’ve improved with this computerized medium. The drawing is fine, except that I gave Barbourofelis a tail that was too long (digitally fixed now), but the color rendering was primitive. My thanks to the editor, David Loeb, for letting me experiment on his dime.

One of the problems with having killing teeth like this was eating the meat once it was secured. Barbourofelis solved the problem by having robust incisors and shearing carnassial teeth to strip and slice meat from bone. Utilizing the carnassials must have been problematic, because the animal had to move its cheek out of the way behind and outside the sabers. You don’t have a 5 million year history without solving those gnawing problems. (I’m SO sorry! I couldn’t stop myself.)

The trouble with a post like this is that it’s a book in the making. There is so much to draw and write about, and so many questions yet to be answered, that I really don’t know what to leave out and what tidbit people might find most interesting. For instance, looking at the paintings the one thing you can’t help but notice is the dependent flange on the mandible of the animals. These protected the sabers when the mouth was closed and there was little room to spare between the saber and the bone of the lower jaw. Maybe I’ve missed it, but I can’t recall having seen anybody paint this as the gum-lined half sheath I’ve portrayed here. There certainly wasn’t enough room for hair to grow, and unless the tooth was supported by being in contact with the flange, it would have defeated its supposed purpose. (I should add that the dirk-toothed felids like Smilodon didn’t have the flange. This is such fun.)

I want to note that things will be changing here at Olduvai George soon. I’ll have an announcement next week about some exciting new developments that will help me to post more often and include more new illustrations. New old whales are coming.

I was hoping to have Kutchicetus up this week but I haven’t nailed the look yet as the new work is based on material I hadn’t seen until last week. 2007 promises to be a very busy year.

I just start blogging again, and I’m suddenly busy with more paying work than I’ve had all year. Out of necessity, I’m posting an older acrylic painting and putting off another post on early whales until next week. I’m sorry, but this is good for me; I do have to make a living. I live in a country of excess and I may have been exaggerating a bit in my “We’re Back” post when I compared my net worth to that of a second rate - third world subsistence farmer, but I certainly am among the blog world’s version of “trailer trash”. The problem is that in my head there are all these things I wanted to do in a certain order, and now I have to change course a little, redirect my energy, and reschedule my timing.

Luckily, the deviation from what I’d planned is fairly small. I’ll still be working on North American ground sloths and other Pleistocene animals and, of course, whales. There might even be a whole new additional website about cetacean evolution and phylogenic relationships.

Today however, I’m posting an acrylic image I did a few years ago. It portrays a time at what is now Fossil Butte National Monument, when southwestern Wyoming looked and felt like Florida.

This image has been seen before at Chris Clarke’s Creek Running North (shameless link, as Chris is back blogging). The head of the massive Brontops emerging from the river can also be found at PZ Myers‘ Pharyngula (another absolutely shameless link - I always get many more hits when PZ links to me), as one of his many revolving header illustrations. Brontops was the culmination of his line. Eight feet (2.3 meters) to the high point of his back, this final “thunder beast” died out at the end of the Eocene, leaving its relatives - horses, rhinos, and tapirs - to carry on the business of being perissodactyls.

Speaking of rhinos, the smaller animal getting out of Brontops‘ path is the early “running rhino” Hyracodon. While small here, its close relatives in Asia would evolve into the largest land mammal yet discovered, Paraceratherium (formerly the Baluchitherium or Indricotherium of my childhood). Hyracodon’s build was very horselike. In fact, while skeletal and dental characteristics identify Hyracodon as a rhino, superficial features may well have been extremely close to its contemporary, the three-toed horse Mesohippus. Had I placed the neck a bit higher on the shoulders and moved the orbit further back on a slightly more gracile skull, I could well have used the same painted image as representative of that small, browsing horse.

And now, just because I can…

This painting is another private commission piece done in the late 1990s. It has absolutely nothing whatsoever to do with the previous image except that I painted them both in acrylic on canvas within the same year.

This little prosimian is the lesser bush-baby, Galago senegalensis, a current resident of dry forest and thorn bush regions of Africa.

Both of these paintings were scanned off the originals on my first small scanner and had to be pieced together in Photoshop. At least at this size I did seem to blend the pieces back together well enough. The only thing lost from the originals was some of the subtlety of color (especially in the skies). Back with more whales and other things next week.

I’ve never painted anything that approached iconic, but this acrylic image of the early transistional whale Ambulocetus natans is certainly the closest I’ve come. I’m betting that most of the readers of this blog have seen it somewhere before. Based on a little pen and ink drawing I had done for my friend Carl Zimmer’s great book, At the Water’s Edge, it has now appeared in a score of books and has illustrated at least a dozen magazine articles.

Click here to see a much larger version.

I remember visiting Hans Thewissen in his lab at NEOUCOM in Rootsville, Ohio. It was after I had sent him the painting, and the second I saw the real material I said “damn, I made the femur too long!”

In doing the drawings for Zimmer’s book, I had consulted with Dr. Hans Thewissen, who had found the fossils of Ambulocetus in Eocene (approximately 49 million year old) rock in Pakistan. Hans and I became friends, and in appreciation for his help, I painted the image for his lab at Northeastern Ohio Universities College of Medicine (NEOUCOM) where he teaches Gross Human Anatomy to future doctors to facilitate his passion for protowhales and other early Cenozoic mammals.

When dealing artistically with an animal like Ambulocetus, for which there are no modern analogs except seemingly bizarre combinations like crocodile/seal, I remind myself (just as with Pakicetus) not to think about it as halfway to something else. Ambulocetus was a large (11 to 12 feet long), powerful and successful animal of its time. Looking at creatures that live in similar habitats today, comparing features, and staying true to the bones (at least the measurements and photos I was given - new discoveries change things all the time) I try to keep my imagination and my ego in check. When I’m working with a scientist who has spent years studying some particular creature, what I want to produce is the animal that they see when they close their eyes and think of their subject as an animated living being.

Here’s an early version of Ambulo I call my fur seal phase. Too much hair and bulk for me today, but the drawing shows the splay-legged stance and outward rotated hand. Its name may mean “walking/swimming whale” but it must have been very clumsy on land and incapable of anything we’d think of as a normal mammalian walking stride.

I’ve drawn or painted Ambulocetus a dozen times - pelted, haired and naked - and I’ve never gotten it right. I’ll never know its color pattern, the length or density of its hair or the exact amount of muscle or fat on its frame. Those qualities are beyond the scope of what we can ever absolutely know, and exterior features can evolve very quickly. What I can do is be as conscientious as possible in proposing a look by considering as many factors as possible and providing reasonable external characteristics for the proposed lifestyle.

Fossils of Ambulocetus are found only in deposits that indicate the environment was near-shore marine and swampy or brackish. At the time, the site of discovery in what are now mountains in Pakistan, was a warm, shallow sea and tidal river delta. I gave Ambulocetus very little in the way of fat or blubber, as it simply wouldn’t have been needed for insulation and its ancestors had evolved in the even warmer world of the earliest Eocene. Originally, I portrayed it attacking and removing a primitive perissodactyl (horse, rhino, tapir or brontothere - you choose) from the gene pool, but in this latest version I have it hunting crabs in a tidal shallows. Perhaps not so animated, but still predatory, and I think, quite a beautiful beast.

Click here to view a much larger image

Or click here to see Ambulocetus without the distortion imposed by integrating the animal into a full painting

I’ve painted its face as hairless except for the robust vibrissae, for grubbing along the Tethys’ shoreline hunting for mollusks, and I’ve also scarred his snout, neck and shoulders from imagined battles with competing males. That formidable head and those impressive teeth seem to me not just for crushing mollusks and crustaceans or for capturing fish, but for gaping, ritualistic displays to intimidate rivals, and if push comes to shove, actual combat. O.K., I said just a couple paragraphs ago I keep my imagination out of it, but after the construction is done, you have to come up with ways to make the animal alive, and that involves behavior. Besides, considering the displays of hippos and other related artiodactyls today, it’s not such a stretch. I’ve also taken some license with the coloring here. If I were doing this for a museum display, I’d probably make the animal darker and mottled or even faintly striped above and light below to better blend the hunter into its background. Here the object is to show the proportions and anatomy, and I didn’t want a camouflage pattern to interfere with actual contour.

I’ve talked a little of the difficulties of recreating long extinct animals and touched very briefly, in my Pakicetus post, on the complications of understanding what lineage diverged when, and from exactly what, in the evolutionary process. While I look at each creature I draw as an individual and complete entity, our knowledge of them and the science behind it is an evolutionary process itself. As with so many other things, our journey of discovery about whales and their ancestors is really just beginning. Yes, we know quite a bit, but in our written history of over 5,000 years, we’ve only been developing the methodolgy for looking at the world around us rationally for the past few centuries. Dr. Phil Gingerich found that first Pakicetus skull less than 30 years ago, and Dr. Thewissen found Ambulocetus in the early 1990s. Rodhocetus, Kutchicetus and others, coming soon to a blog near you, have all been unearthed within the last 10 years, and DNA and other biochemical work is in its precocious, brilliant infancy; stay tuned!