Jaime's new-look Andrewsarchus

You may recall that we had a bit of an Andrewsarchus thing going on here back in August. As you'll know if you followed the articles in question, there is now some suggestion that Andrewsarchus was not the megawolf mesonychian once imagined, but instead a weird relative of those entelodont giant killer pigs from hell. Inspired by this suggestion, a few artists have started to re-imagineer the animal. The other day I was very happy to see the following brand-new piece of art, produced by Tet Zoo regular Jaime Chirinos of Zooartistica (image © Jaime Chirinos, used with permission)...


Jaime's work has appeared here before (see Of dragons, marsupial lions and the sixth digits of elephants: functional anatomy part II and Giant killer pigs from hell). My question is: what exactly are those gulls? :)

For previous musings on Andrewsarchus see...


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The previous article was a brief, cursory introduction to the mesonychians. Time to look at things in a bit more detail... Andrewsarchus mongoliensis is, of course, 'the' mesonychian for most people, and one might get the impression that it's a typical member of the group. In fact it's most…
We saw in the previous article that Andrewsarchus, most 'famous' of mesonychians (even though it may well not be a member of this group), is not just a scaled-up Eocene wolf, but really something quite unusual. Indeed, it's so unusual that Szalay & Gould (1966) decided that it's worthy of its…
We now move to another mesonychian group: Hapalodectidae. This is yet another of those obscure little groups that sounds really interesting, yet are never the subject of focus or discussion. Virtually all of the literature on them - and that's still only ten papers or so - mentions the idea that…
Time to finish with the mesonychians. Previous articles have looked at Andrewsarchus and the triisodontids, the mesonychids, and the hapalodectids. That's essentially it... though - as mentioned a few times now - Andrewsarchus doesn't seem to be a mesonychian after all. However, there are a number…

Really a great reconstruction. The colouration reminds me a bit to those of an eland antelope, what makes a good analogy to those huge and bulky modern animals.

Nice, but on balance I think I still prefer the Carl Buell version. Not sure why - aesthetic appeal can be hard to define.

Interesting that this one is shown running along the seashore. An odd choice, given that the only fossils we have are from the middle of Mongolia, presumably as far from the coast then as it is now. "Walking with Beasts" did the same as I recall. Do the deposits the fossils were found in give any clues as to the environment Andrewsarchus actually inhabited?

Remember: Andrewsarchus is known but from a single skull--no jaws, no postcranials. At one time when it was considered sister-group to whales, you could have reconstructed its postcranials like those of an archaeocete whale--except for the fact that it comes from terrestrial beds in Mongolia (but then Pakicetus and Ambulocetus also come from marginal marine/terrestrial beds as well).

Very nice image. I find it a bit hard to get a proper sense of Andrewsarchus' huge size though. Given that its skull length was 83+ cm, what would be the shoulder height and the body length of the animal in that reconstruction? (I can guesstimate them, but would like to hear Jaime's opinion, if possible.)


The colouration reminds me a bit to those of an eland antelope

Or rather more like that of a bongo antelope, perhaps?


Interesting that this one is shown running along the seashore. An odd choice, given that the only fossils we have are from the middle of Mongolia, presumably as far from the coast then as it is now.

Here is a map of the world in the Eocene. "Mongolia" would have been landlocked even back then (although admittedly it was closer to the sea, especially in the west and in the south).


what exactly are those gulls?

The LCA of Larus and Chroicocephalus...?

At the moment I agree with those who are saying that the 'Cerro Azul monster' is a sloth that (for some reason) lacks hair.

J.S. Lopes-

As reported in yesterday's Forgetomori, the
strange creature is almost certainly a sloth.

Great image, indeed-the proportions look a lot more

By Craig York (not verified) on 17 Sep 2009 #permalink

Craig: re 'more porcine', you're talking about Jaime's Andrewsarchus, not the Cerro Azul creature, right?

Shouldn't the eyes be placed quite a bit further down on the sides?

Darren-Oh yes, definitely the Andrewsarchus! Its
not terribly relevant, but I've always found pigs-as-
predators a lot more scary than the more common large

By Craig York (not verified) on 17 Sep 2009 #permalink

The question of Andrewsarchus running along the seashore is a good one. For some reason I find it important that artists do indeed have some kind of freedom when it comes to stuff we don't know everything about. Anatomy (and similar) is of course important for artists working with scientific topics. But I believe its sometimes important to break away from the norm. Sometimes a bit dangerous. I once made two Homotherium in a snow covered forrest. The idea was that they - kind of - took shelter among nearby trees during a sudden snowfall. The viewer whithout imagination reads the illustration as the norm might start believing that the cats allways lived in both snow and forrests. Either that or they write the picture off as plain wrong.

Illustrations (reconstructions) are perhaps mostly useful when they doesn't differ from the known facts and when they show an animal in its typacal habitat.
Or in this case - the habitat we think they lived in.
But animals - extinct and extant - are/were living creatures and not easy to direct or to put into a box. I think its exciting with the seashore and the gulls.

And they have occational snow storms in the mediterranean countries too. And Im bloody sure that some Homotherium cats encountered snow at some point.

Dartian, yes it loos even more than the fur of a bongo antelope. I had to think at elands at first, because not much more than a week ago, I have seen a huge and really beautyfull bull eland at a danish zoo.
I found the idea presented at "WWPB" that Andrewsarchus patrolled often at shores to find carrion and turtles very unprobable. The shores of the sea are a very restricted area for a terrestrial predator, especially for one of such huge size, so a specialication for this special habitat is extremely unlikely. Of course brown hyenas, grizzlies and even jaguars feed sometimes in this way, but only a comparably small part of the total population lives in this way.

Walking with Beasts actually has the narrator say that Andrewsarchus normally hunts inland, but has been driven from his normal hunting grounds to the coast by drought.

By Andreas Johansson (not verified) on 17 Sep 2009 #permalink

Nice, and interesting how illustrations can be useful to informally consider hypotheses.
I like the more artiodactyl/hippo-like legs and feet better than the way it looked in Buell's piece, which seemed more wolf-like to me, but here the head ends up looking very out of place on an entelodont-like body- so perhaps this sheds some light on Andrewsarchus's affinities?
Also I agree with #9, I thought the eyes should be a little further down.

I agree that the notion of an apex predator like Andrewsarchus being a beach dwelling specialist is so improbable that it can be ruled out. It's hard even to think of small mammalian predators being restricted to such a niche.

Not to hijack the thread, but it's interesting to speculate what bearing the discovery of (the terribly named) Raptorex has on theories of Tyrannosaur lifestyle and diet:

If T. rex was an obligate scavenger because it was a big lumbering brute with tiny arms, then what do we make of a presumably quick, agile predecessor, also with miniature forelimbs?

By Ranjit Suresh (not verified) on 17 Sep 2009 #permalink

>"I agree that the notion of an apex predator like Andrewsarchus being a beach dwelling
> specialist is so improbable that it can be ruled out. It's hard even to think of small
> mammalian predators being restricted to such a niche."

Not entirely sure I understood you correctly. Is your comment related to the actual reconstruction above or more a general viewpoint?
If it's in connection to the Andrewsarchus-painting I'd still like to say that I don't think one should read illustrations as straight forwad static information.

It's like seeing a picture of a bat brain eating tit and believing that they do nothing else but eating those bat brains.

There are some serious issues with the interpretation of the skull of Andrewsarchus, and my recent postdoc Erich Fitzgerald is looking at them. The more entelodont reconstruction above does not address them.

By Hans Sues (not verified) on 17 Sep 2009 #permalink

It's definitely a lot better than most of the reconstructions I've seen, although the jaw ruff is still very wolfish.

Actually, judging by the hair growth you see in cetaceans and pigs, I'm envisioning it with whiskers like a Schnauzer...

It certainly is nice, but I'm not much for digital art. I like traditional paintings better.

By M. O. Erickson (not verified) on 17 Sep 2009 #permalink

The first thing I thought when I saw the illustration was a bush pig due to it's coat. I don't think bush pigs have white stripes though, but the orange to black coloration seemed reminiscent.

I still think Carl'd version needs a grain of salt, as it is more like a lion.

By Tim Morris (not verified) on 17 Sep 2009 #permalink

Hans- Looking forward to it. Can't we just go look for new material too though? I mean we already have like 6 T rexes..
'Fac, I don't notice prominent whiskers on pigs, and one might also look at analogous large predators that don't really have rodent-like whisker protrusions, like wolves tigers and lions. Finally I agree the Buell body looks a bit too lionish, down to the architecture of the legs and feet (I like the original painting by Charles Knight I think where the predator and prey both have the same artiodactyl hooved feet..but perhaps that goes too far.) But I really don't see an entelodont resemblence in the Andrewsarchus skull. It has no protrusions, even mild ones, as do the entelodonts (zygomatic arches shouldn't count). Assuming it is a mesonychian, its relatives don't either (although that sort of obsolesces the question of entelodont relations)

Sorry guys, but I don't like it at all. Most bugging to me is the fact that the eyes should have been way further down the skull. The beast itself also looks too small to me, compared to the gulls.
I'll also have to agree that digital pictures just don't look that good.

Sorry to be the sourpuss here.

Ranjit Suresh: the idea of T-rex being an obligate scavenger is highly unprobable for a lot of reasons, and the small size of its arms is also surely not a reason against active hunting or for scavenging.
Rober: The two Homotheriums in the snow look really very cool. I find it good if not only completely sterotypical scenes are painted, but also such ones which occured probably not on a very regularly. There is for example a very cool paleo-painting (sadly I don´t know the artist´s name anymore), which shows several stegodons floating in the sea with a Megalodon below them. This was surely not a common scene too, but it probably happened once, and it looks really cool. Your Meganeura feeding on a Hylonomus is also great. Given the huge size of Meganeura,it would also be a bit strange if it was restricted to hunt flying prey as modern dragonflies.

Correction, the picture I was referring to was John Sibbick and not Charles Knight

Overall wonderful image, I love the shading and fur.
My only artistic critiques are that the horizon lines up too well with the back and the other beach elements are too linear to feel "natural". Anatomically, the eye needs to be repositioned further down.
Perhaps giving the back a little more of an angle to break up the horizon line and the overall strong linear feel of the image?

^AD, it was meant to be a joke. Although the bearded pig does have a mustache.

Pardon my ignorance, but are those seagulls or some sort of birds that resembled seagulls (smallish pseudodontorns/whatever)?

'Fac, it seems like a lot of Andy reconstructions for some reason include a weasel-like prominently bewhiskered snout, for which I just don't see any basis..but thx for the clarification

Homotherium in forest? Why not?

I think at least in European pleistocene there was quite a lot of forest, even in glacial period patches of forest must have remained (as evidenced by bones of many forest birds). And Homotherium leg structure suggests moderate climbing ability (this after Beringia). So Homotherium resting on tree branch would ba also good.

Sordes: Thanks.

Jerzy: Thanks to you as well. Realize I wasn't mentioning the real reason why I brought up the question about these two cats among the trees. It was simply because a person with a profession in prehistoric life actually wrote the painting off simply because it didn't follow standard viewpoints of the environment in which the cat lived.
But at the time I didn't fancy yet another Homotherium-out-in-the-grassland-painting.

However I also understand that scientists often wants to be a bit careful about how to illustrate these things. It sometimes gan get really wrong or give the wrong picture.

I am loving this!

Yeah, the eye should be placed lower on the skull. This is an oddity of Andrewsarchus that doesn't seem to fit the terrestrial predator paradigm, and a lot of artists struggle with it. I read somewhere that birds like herons have their eyes placed low on their heads the better to see and manipulate fish at the end of their long beaks. I wonder if something similar might be going on with long-jawed Andrewsarchus, if it ate a lot of fish.

But I like this image. I like the color and the action. And the more and more varied interpretations of Andrewsarchus the better, as far as I'm concerned. I am fascinated by this animal.

If I may toot my own horn very softly, I once attempted a relatively crude pencil sketch of an Andrewsarchus here. (Alas, it is not helped by the fact that I had to scan it in with a rather limited low-rex scanner.) Coincidentally, my choice of markings was inspired by the bongo and the red river hog as might have been the case above.

Afterward, I thought I went overboard in making too much resemble a modern ungulate, as the body is a lot more like a stiffed-bodied hoofed mammal's than supple like a carnivore's, but after reading recent discussions here, maybe that is not such a problem after all.

Someday I would like to try an image of an Andrewsarchus trotting jauntily out of a wooded stream with a large Asian catfish in its jaws. (But first I have to research how long catfish have been in Asia, I guess.)

By Stevo Darkly (not verified) on 20 Sep 2009 #permalink

Sorry, I think I messed up that link to the sketch. It's here.

By Stevo Darkly (not verified) on 20 Sep 2009 #permalink


first I have to research how long catfish have been in Asia

Fossil catfish vertebrae have been found at the very same Mongolian locality of Irdin Manha that yielded the skull of Andrewsarchus (Stucky, 1982).


Stucky, R.K. 1982. Early fossil catfish from Mongolia. Copeia 1982, 465-467.

Oops, I almost missed Ranjit's comment #15:

the notion of an apex predator like Andrewsarchus being a beach dwelling specialist is so improbable that it can be ruled out.

Hmm. I guess that depends on your definition of 'beach dwelling'. For example, the polar bear is a large apex predator that forages mainly, or even near-exclusively, at the land-sea interface. (Note that I'm not suggesting that Andrewsarchus had a similar lifestyle; I'm just playing devil's advocate by pointing out that even large, basically terrestrial carnivores may successfully adapt to very specialised ecological niches.)

It's hard even to think of small mammalian predators being restricted to such a niche.

Hard but not impossible; the recently extinct sea mink Neovison macrodon seems to have been restricted to such a coastal existence.

Finally, to cut the artist some more slack; that need not necessarily be a seashore our Andrewsarchus is running along. It could also be the shoreline of a large lake (like, say, some ur-Baikal). The gulls present no problem for that interpretation; many gull species live preferentially by freshwater.

Dartian, thank you!

(By "I need to research" I obviously mean "I need to casually mention my question in a forum full of knowledgeable and helpful people.") :)

By Stevo Darkly (not verified) on 21 Sep 2009 #permalink

Dartian: I don´t think that polar bears and sea minks are good comparisons. The sea mink did feed on very small animals, which it caught possibly to a part even in the water. So it would need most probably an amphibic way of life to specialice to a exlusively coast-dwelling predator. There was actually such an animal, the "oyster-bear" Kolponomos (which was no real bear at all), which was a specialiced amphibic mollusc eater. It became possibly extinct as a result of competition with early walerus species which were better adapted for this special food. Of course I know that racoons and even grizzlies sometimes exploit the sea shore in search for mussels and crabs, but this are only side issues among the whole population. I have also a hard time imagine Andrewsarchus feeding on tiny crabs and molluscs...
The comparison with polar bears is also not that good, because they live mainly on the ice, and not at the coasts. The special conditions in this environment enables them to prey on seals, which are distributed over an extremely large area, and not only at coasts.


I don't think that polar bears and sea minks are good comparisons.

I was actually not comparing them to Andrewsarchus specifically. Perhaps I didn't make myself clear enough; I mentioned the polar bear and the sea mink only as examples of carnivorous mammal species that are known to be (or, in the sea mink's case, strongly suspected to be) specialised for foraging in seashore habitats. And my point was that postulating such a lifestyle for an extinct mammalian carnivore need not be an wildly outlandish idea, at least not in principle.

As for Andrewsarchus specifically: as long as all we have of this beast is one incomplete skull I personally think it's somewhat futile to compare it to anything in terms of its ecology or behaviour. As is so often the case, we need a lot more fossils. But if I'd now have to make a complete wild-arse guess, I'd say that no, Andrewsarchus probably did not sustain itself by beachcombing.

[polar bears] live mainly on the ice, and not at the coasts

I chose my terminology in comment #39 quite deliberately*. I wrote 'forages', not 'lives', because establishing where an animal typically feeds is more straightforward than establishing where it "lives" (which is something much more vague). And I wrote 'land-sea interface', not 'coasts', because the former phrase is more inclusive and also covers the pack ice habitat where the polar bear so often does its hunting.

* Or, as some dead dude once put it: 'Though this be madness, yet there is method in't.'

I did understand what you mean, and as I wrote, there was actually really a large carnivore which was restricted to life and feed on the shores of the sea, so the idea of such a way of life is not absurd at all.
Of course we know only very little about Andrewsarchus, not even its actual size, be we can be very sure that it was huge, and surely needed a whole lot to eat. Furthermore we can speculate that the population density was comparably low, at least if it was a carnivore and not an omnivore. For ecological reasons animals like Kolponomos can be perhaps compare with herbivores, as they feed on immobile food which occured in high masses. But there seems no adaption for a mollusc or at least fish-eating specialication in the skull of Andrewsarchus, and a pure carrion feeder restricted to coast lines seems also unlikely.
Okay, I have to admit that I really read over the words "forage" and "land-sea interference".

"But there seems no adaption for a mollusc or at least fish-eating specialication in the skull of Andrewsarchus"

I am not an expert, but I have to raise a question about that, with regard to fish-eating specialization.

The elongated and relatively narrowed jaws of Andrewsarchus remind me of the kind of elongation and narrowing you see in aquatic crocodilians (to a greater or lesser degree, depending on how much they specialize in eating fish), spinosaurs, storks and herons.

Plus there's the unusually low placement of the eyes on the sides of the head. Again, this reminds me of the time I read that the eyes of storks and herons were placed relatively low on the sides of their heads so they could better see, and manipulate, fish caught at the ends of their elongaged beaks. (You might expect the same of crocodilians, but of course the extant species also specialize in lying watchfully in the water, a lifestyle that rewards the evolution of eyes placed high on the skull. If, instead of lying in the water, crocodilians prowled the banks and shallows on stiltlike legs, their eye placement would probably be different.)

I wonder if the best model for the lifestyle of Andrewsarchus might be to envision something like a bear with the skull of a stork but the jaws of crocodile. Such a beast would live on land rather than be aquatic, yet have some specialization for catching fish. At the same time, it would also be able to take other prey, including other large land animals that wandered down to the water for a drink. Perhaps by ambushing them from the vegetation near the water (instead of from the water itself as crocodiles do).

Or ... am I crazy?

By Stevo Darkly (not verified) on 22 Sep 2009 #permalink

Relationships of Cetacea (Artiodactyla) Among
Mammals: Increased Taxon Sampling Alters
Interpretations of Key Fossils and Character Evolution
Michelle Spaulding1,2*, Maureen A. OâLeary3, John Gatesy4

I apologise for any insolence, but the three best renditions of this animal still cry wolf, so to speak.

I personally think that this animal, being a "hippo" could possibly have a more hippo-like anatomy, coupled with a longer tail. The result is perhaps too much like kutchicetus crossed with an errant sow, but I digress...

By Tim Morris (not verified) on 10 Oct 2009 #permalink