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Those giant killer pigs from hell aren’t pigs

The views expressed are those of the author and are not necessarily those of Scientific American.


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Whatever noises it made, I bet they were scary.

ResearchBlogging.org

If you’ve been with Tet Zoo since the early days, you’ll have seen this image before – and, even if you haven’t seen it on Tet Zoo you might have seen it anyway, since everyone loves this model and it’s mentioned just about any time that entelodonts are. Yes, it’s an entelodont – a member of a group of fossil artiodactyls that inhabited North America, Eurasia and Africa between the Eocene and Miocene, with the oldest species in the group being those of Middle Eocene Asia.

Entelodonts (properly Entelodontidae) have generally been regarded as suiforms (close kin to pigs and peccaries) but some recent analyses have found the sampled members of the group to be members of the hippo + cetacean clade Cetancodontamorpha (O’Leary & Gatesy 2008, Spaulding et al. 2009) and hence fairly well removed phylogenetically from pigs and peccaries. Andrewsarchus, the famous Eocene giant predator or omnivore so often regarded as a mesonychian (or mesonychid), seems to be a cetancodontamorphan close to entelodonts (see the links below for much more on Andrewsarchus).

Anyway, the awesome life-sized model you see in the photos above depicts the Oligocene-Miocene North American entelodont Daeodon (formerly better known by its synonym Dinohyus) and is on display at the Denver Museum of Nature and Science. It’s a shame there’s no scale in these photos: Daeodon was huge (c. 1.8 m tall at the shoulder). The model is fantastically accurate. It even has snot in its nostrils.

A pile of half-eaten specimens of the small camelid Poebrotherium show that the entelodont Archaeotherium was in the habit of grabbing these little herbivores, bringing them back to a cache site, and consuming them. Or, at least _one_ Archaeotherium was doing this, anyway. See Sundell (1999).

Entelodonts are widely regarded as omnivores that scavenged dead animals and, at least sometimes, caught and ate live ones. Evidence for this omnivorous lifestyle comes from their pointed incisors, recurved, pointed, serrated canines*, serrated premolars and an unusually mobile** jaw joint. Further evidence comes from studies on bite strength (Effinger 1998, Joeckel 1990) and from bite marks left on the bones of other mammals (Hunt 2005). Oh yeah, and there’s the discovery of a pile of bitten-in-half little camels from the Early Oligocene, the marks on their bones matching the tooth anatomy of the entelodont Archaeotherium (Sundell 1999) [the adjacent illustration depicting this scene comes from Kent Sundell’s page here]. Massive bony cheek flanges and bony tubercles on the lower jaw might have been used in intraspecific fights, and some specimens preserve skull injuries apparently inflicted by other entelodonts.

* The canines were serrated in juveniles, but the serrations generally became worn away during ontogeny.

** Unusually mobile for an artiodactyl that is.

The postcranial morphology of entelodonts is remarked upon less often than their skull anatomy. Even giant forms had a surprisingly gracile, slender neck. Large neural spines on the anterior thoracic vertebrae show that very large nuchal ligaments were present: the anterior thoracic neural spines of Daeodon are almost on par with those of bison and other tall-spined ungulates. Entelodonts were strongly cursorial, with elongate and slender limbs where the radius and ulna, and tibia and fibula, are often fused together. Unlike pigs, entelodonts were didactyl. Not only were they nasty and with a frightening dentition, they were also fast!

Here’s another entelodont rendition, this time showing Entelodon from the Late Eocene and Early Oligocene of western Europe, Kazakhstan, China, Mongolia and Japan (it’s probably the most widely distributed entelodont). The image is kindly provided by Jaime Chirinos of zooartistica.com and is used with permission.

Entelodon, by Jaime Chirinos.

Entelodon was closely related to Late Eocene-Oligocene Archaeotherium from North America and was a large entelodont, with good remains of E. deguilhemi from France showing that it reached 1.3 m at the shoulder, and 65 cm in skull length. Archaeotherium and Entelodon had shallower skulls than Daeodon, but they would still have been formidable predators and scavengers. In the illustration here they’re feeding on a dead horse.

And I only decided to recycle all of this stuff because I also just featured that peccary article from a few days ago. While looking at entelodont images online, I found this one by my good friend Luis Rey. If you work on dinosaurs you might be rather offended, but isn’t that why we’re here?

Not all mammals are rodents.

For previous Tet Zoo articles on entelodonts, Andrewsarchus and various of their friends and relatives, see…

Refs – -

Effinger, J. A. 1998. Entelodontidae. In Janis, C. M., Scott, K. M. & Jacobs, L. L. (eds) Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals. Cambridge University Press, pp. 375-380.

Hunt, R. M. 2005. An Early Miocene dome-skulled chalicothere from the “Arikaree” conglomerates of Darton: calibrating the ages of High Plains paleovalleys against Rocky Mountain tectonism. American Museum Novitates 3486, 1-4.

Joeckel, R. M. (1990). A functional interpretation of the masticatory system and paleoecology of entelodonts Paleobiology, 16, 459-482

O’Leary, M. A. & Gatesy, J. 2008. Impact of increased character sampling on the phylogeny of Cetartiodactyla (Mammalia): combined analysis including fossils. Cladistics 24, 397-442.

Spaulding, M., O’Leary, M. A. & Gatesy, J. 2009. Relationships of Cetacea (Artiodactyla) among mammals: increased taxon sampling alters interpretations of key fossils and character evolution. PLoS ONE 4(9): e7062. doi: 10.1371/journal.pone.00070672

Sundell, K. A. 1999. Taphonomy of a multiple Poebrotherium kill site – an Archaeotherium meat cache. Journal of Vertebrate Paleontology 19 (Supp. 3), 79A.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. llewelly 7:35 pm 08/25/2011

    NOW we know what caused the extinction of T-Rex …

    It seems to me Andrewsarchus gets moved around a lot.

    Link to this
  2. 2. Bora Zivkovic 8:09 pm 08/25/2011

    Absolutely awesome, brilliant, heart-stopping and scary!

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  3. 3. KarMannJRO 9:56 pm 08/25/2011

    “Whatever noises it made, I bet they were scary.”

    It wouldn’t have mattered if it tweeted like a canary; if it had, our ancestors would have evolved to associate canary tweets with “scary”.

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  4. 4. imhennessy 10:05 pm 08/25/2011

    Scrolling from the bottom of your articles to the comments section is dangerous for me. I just opened three new tabs with articles I want to read now.

    thanks
    Ivan

    Link to this
  5. 5. da bahstid 11:38 pm 08/25/2011

    Almost 6′ tall at the shoulder…big ancient mammals…

    Link to this
  6. 6. Allen Hazen 1:31 am 08/26/2011

    Andrewsarchus seems to gravitate toward whales in classifications: the new story outlined here is that they are close to Entelodonts which are close to Cetancodonts….

    A long time ago (early 1980s?), before the molecular people started everybody looking for whale-artiodactyl connections, Whales were thought to be close to Mesonychians… and at least one cladogram(*) I remember (it was in the Mammals volume of a two-volume Zoological Society of London collection on the “Phylogeny and Classification of the Tetrapods” had Andrewsarchus shown as the “Mesonychid” closest to whales! As I recall, the traits cited to support that included the arrangement of the upper incisors: the plesiomorphic condition has all three more or less side-by-side, whereas early whales had all three arranged in a fore-and-aft line. And Andrewsarchus, i.i.r.c., split the difference: second incisor lateral to first, but third behind second.

    (*) I don’t remember if this was generated by computer search or was “handmade.”

    Link to this
  7. 7. BrianL 3:09 am 08/26/2011

    Given their likely relationships, I’d much prefer describing entelodonts as ‘hunting hippos’ or ‘running hippos’ (carnocursippos?) over ‘giant killer pigs’. In fact, I imagine that a living entelodont may well have looked like an athletic and sleek hippopotamus,rather than like a pig.

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  8. 8. anzha 12:34 pm 08/26/2011

    Just out of curiosity, has anyone ever compared the entelodonts to the diademodonts of the Triassic? For some reason looking at the skulls the remind me of each other…

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  9. 9. Andreas Johansson 1:01 pm 08/26/2011

    Why is that tyrannosaur looking so blue?

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  10. 10. John Harshman 2:56 pm 08/26/2011

    There may be some problems of scale with that last illustration. Perhaps if you stuck Michaelangelo’s David somewhere in the picture?

    Link to this
  11. 11. Jerzy New 6:15 pm 08/26/2011

    I wonder if there were canids, hyenas or similar running carnivores in these ecosystems?

    Link to this
  12. 12. Heteromeles 7:27 pm 08/26/2011

    So the idea is that hippos evolved from omnivorous or carnivorous ancestors?

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  13. 13. naishd 2:33 am 08/27/2011

    Interesting comments, thanks everyone. Some responses…

    BrianL (comment 7): you may well be right. Mostly for reasons of tradition, entelodonts have generally been pictured as ‘super-pigs’ (look at the mane they’re typically shown with). But we don’t know anything about their integument really.

    anzha (comment 8): if you see a superficial similarity, it’s definitely superficial. Entelodonts are unambiguous artiodactyls, and hence deeply nested within crown-group Mammalia.

    Jerzy (comment 11): entelodonts were around for a long time (Eocene to Miocene) and lived across four continents, so they lived alongside most Cenozoic animals you might think of. Giant, North American Daeodon, to take one example, is from faunal assemblages that also include amphicyonids (‘bear-dogs’), various (mostly small) borophagine canids, nimravines (‘false sabretooths’) and assorted mustelids.

    Heteromeles: I suppose it’s likely that a degree of omnivory was widespread across the cladogram artiodactyl, being retained by all groups with an ancestrally bunodont dentition. Cetaceans and hippos thus descended from omnivorous ancestors – cetaceans didn’t descend from strictly herbivorous ancestors (as you might assume given their position within Artiodactyla).

    Darren

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  14. 14. puppygod 5:16 am 08/27/2011

    So… Should we call them landorcas now?

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  15. 15. BrianL 8:27 am 08/27/2011

    Hold your horses there, puppygod! I already coined them hunting hippos and that’s final! That being said, I do wonder if my ‘carnicursippos’ was too corny. Perhaps it was.

    Link to this
  16. 16. BilBy 9:06 am 08/27/2011

    @BrianL – ‘carnicursippos’ is good, but ‘hippo’ just means ‘horse’ after all. You need another word for that part of the name or they are just carnivorous running ponies, which is only -moderately- terrifying :)

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  17. 17. WarrenJB 11:34 am 08/27/2011

    “I’d much prefer describing entelodonts as ‘hunting hippos’ or ‘running hippos’… I imagine that a living entelodont may well have looked like an athletic and sleek hippopotamus.”

    Not to turn this into Tony Hart’s gallery, but that’s what I went with: http://tinyurl.com/3rmf7pw
    All the doglike, baboon-like and even reptile-like snouts I’ve seen on entelodont restorations didn’t seem quite right to me, particularly after noticing superficial similarities with hippo skulls; though I can’t claim any marvellous insight or painstaking research. But given the phylogeny mentioned, can we assume that for palaeoart, ‘vaguely hippo-like’ is a safe bet (safer than most)?
    (Also, the drawing’s old, nothing spectacular, and could benefit from a lot more effort and expertise; but if anyone still wants to poke holes in it and tell me why I’m wrong – maybe elsewhere – I’m all too pleased to listen.)

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  18. 18. BrianL 12:50 pm 08/27/2011

    Bilby, how about carnicursipotami, with carnicursipotamus being the singular?:)

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  19. 19. Heteromeles 3:24 pm 08/27/2011

    Well, hippocampus (horse of the plains) would be equivalent to hippopotamus (horse of the water), but that’s taken already, I think.

    Referencing the man-eating Mares of Diomedes might also be appropriate…Hippodiomedea?

    Link to this
  20. 20. josimo70 5:16 pm 08/27/2011

    Hippocampus means “horse-caterpillar”. Kampos is Greek for “caterpillar”.

    Link to this
  21. 21. josimo70 5:19 pm 08/27/2011

    Stem Cetartiodactyls seems plausibly omnivorous, but basal Perissodactyls were herbivorous.

    Link to this
  22. 22. Heteromeles 5:52 pm 08/27/2011

    Or campos means “sea monster” in Greek, if one believes Wikipedia, which is always problematic. The real point is that “hippopotamus” is river horse or water horse, so focusing on the -potamus suffix for a name makes for issues when talking about the dry-land antecedents.

    Since there are meat-eating horses (“hippos”) in mythology and apparently in fact (http://www.horsetalk.co.nz/features/meateatinghorses-190.shtml), I thought that might be a good source for potential clade names.

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  23. 23. Strangetruther 5:53 pm 08/27/2011

    Hippocampus means Sea Horse.

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  24. 24. BilBy 2:07 pm 08/28/2011

    @Strangetruther – Hippocampus is a generic name for seahorse, but wouldn’t a ‘sea horse’ be (sensu hippo potamos) ‘hippothalassos’? Having been recently bitten by a grumpy horse I’m pretty sure it would be a horribly painful way to go

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  25. 25. pmurphy98 9:11 pm 08/28/2011

    “Those Giant Killer Pigs from Hell Aren’t Pigs.”

    The important thing is that they still are giant, still killer, and are still from hell.

    Link to this
  26. 26. naishd 7:38 am 08/29/2011

    … yes, that’s the general idea I was going for :)

    Darren

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  27. 27. DVMKurmes 10:37 pm 08/30/2011

    That model at the Denver Museum was the only thing that really bothered my daughter when she was young. None of the other realistic dioramas of dinosaurs, sharks, etc. bothered her, but the Entelodont scared her. This was a kid who could watch Jurassic park at the age of 5, and just needed a little reassurance that T-rex was indeed extinct. She did not want to stay anywhere near the entelodont display. Giant hellish killers indeed.

    Link to this

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