Tetrapod Zoology

Yeah, things are still tough here at Tet Zoo Towers, and the time needed for blog-writing has yet to materialise. But the end is in sight, and things will be back to normal within the next few weeks. I hope.

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If you’ve been reading the series of babirusa articles – and, hey, who hasn’t? – you’ll recall the mention of that most sought-after of objects: a male babirusa skull where one of the upper canines has pierced the frontal bone, and grown into the skull… perhaps with fatal consequences. Given the extraordinary form of the canines, it seems obvious and perhaps inevitable that at least one individual like this must exist. Some friends and correspondents say that they’ve seen a skull (or a photo of a skull) where this has happened, yet no-one has been able to show me the goods. Until now…

Yes, thanks to Tet Zoo reader and all round good-egg Henrik Petersson I’ve learnt within the last couple of weeks that a babirusa skull at the Museum of Natural History in Gothemburg (Sweden) shows exactly what we want to see. It’s an old male with spectacular tusks, and the animal’s right upper tusk has grown into its skull (for reasons that will become clear below, we’ll call this skull ‘skull 1′). Did this overgrowth of the tooth kill the animal? Unfortunately, we don’t know, as the original label that accompanied the specimen is missing. We do know that the skull is one of about 60 that were obtained by Walter Kaudern while he was on survey on Sulawesi between 1916 and 1920.

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Some of you might have seen Henrik bringing attention to this skull in the Tet Zoo comments a while ago. I hid his comment – with his permission – because I wanted to save the surprise for a dedicated article. Owlmirror picked up on this and even managed to find a black-and-white picture of what seems to be another skull (we’ll call it ‘skull 2′) from the same collection: it’s reproduced at left, and you can see it slightly larger here. Is this definitely a different skull from skull 1? I’m not sure: if you compare skulls 1 and 2 closely they’re very similar; the only obvious difference concerns the lower canines, and these are so freakishly large and robust in skull 1 that I wonder about their authenticity. In other words: could skull 1 merely be skull 2, but fitted out with bigger, meaner-looking lower canines? It would be nice to know more!

So: babirusas can get impaled by their own teeth after all. Note that the individual or individuals shown in these photos have/had particularly long, magnificent canines, so ‘self-impaling’ is only going to happen in old, well ornamented males whose teeth are complete.

Here are more photos of skull 1, many thanks indeed to Henrik Petersson for supplying them.

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For previous babirusa articles see…

And remember that babirusas are being threatened by illegal hunting (they are trapped and killed in central Sulawesi and then transported for sale in the Christian area in the north of the country): for more see Lynn Clayton’s Babirusa.Org.

For other Tet Zoo articles on artiodactyls see…

Comments

  1. #1 tai haku
    March 8, 2010

    holy crap – that is awesome.

  2. #2 mo
    March 8, 2010

    Boom – headshot.

  3. #3 Valagos
    March 8, 2010

    After this last post I can only conclude that either the sexual attractiveness of these tusks for females must be phenomenal or the intimidating effect on other less endowed males must be overwhelming. I don’t see any other reason to carry such cumbersome, expensive, impractical, and obviously dangerous to self structures on their heads. That doesn’t take away from the fact that they are fascinating creatures though.

  4. #4 Alpha
    March 8, 2010

    If you compare the small holes in each skull, you can see that they don’t match. I’m pretty sure skull 1 and skull 2 are from two different animals.

  5. #5 Willy
    March 8, 2010

    I cant imagine the stress that this animal should have had with this canine piercing throug his skull and beeing totally unable to do anything….not even try to brake the tusk agaisnt a hard surface cause it would only penetrate more and the payn must have been terrible!!!

  6. #6 David Marjanović
    March 8, 2010

    the Christian area in the north of the country

    Island.

  7. #7 Oll Lewis
    March 8, 2010

    In favour of the two skulls being different, it may be just the angle of the photograph but the cheek teeth look more worn down in skull 2 than in skull 1.

  8. #8 K Capach
    March 8, 2010

    Is it possible that this has to do with not only age but with the missing left upper tusk? Perhaps the paired tusks would tend to push one another out of the way?

    Good luck with the next few weeks!

  9. #9 Graham
    March 8, 2010

    I think they have mixed up parts of two different skulls. The upper jaw with the impaled canine matches as far as I can tell, there are very similar marks on the tusks. The lower jaw doesn’t match – apart from the tusks, the holes that alpha noticed.

  10. #10 neil
    March 8, 2010

    Wicked. I knew that I had seen a specimen like that but I couldn’t remember where. That natural history museum is fantastic, particularly the blue whale with the upholstered couches inside its body cavity. By the way, I think “Gothenburg” is the preferred English spelling rather than “Gothemburg” though I’m sure David M. will be along shortly to tell us that we should just embrace the diacritics and go with “Göteborg”.

    I’m thinking those are the same skull, that cavity or foramen on the offending canine looks identical in shape and placement as do many of the other small details on the skull (bumps and foramina). The roots look exposed on the lower canines in the color photos, is it possible that they have just been dislocated a bit from the alveoli? Plus, the angle on the black and white photo might be foreshortening the lower canines.

    Re-running the Babirusa series was an awesome move. I really need to track down my 3rd grade teacher Ms. Holloway who brought my parents in to discuss my “overactive imagination” when I gave report about Babirusas to the class.

  11. #11 wheelbrain
    March 8, 2010

    @3 “…and obviously dangerous to self structures on their heads.”

    If only very old males self-impale, and that rarely, they are probably long past their breeding prime by the time that happens, which means this isn’t an issue; most reproducing males never live long enough to have their teeth interfere with their fitness. Teeth that grow too quickly and self-impale too early would be selected against, but so would teeth that grow too slowly and are less impressive than other males of the same age.

  12. #12 Chelydra
    March 8, 2010

    The two skulls definitely appear to be identical. In particular note the large amount of missing bone exposing the root of the hindmost upper molar. To get a better look at the black-and-white photo, follow the link, then open the image in a seperate tab as it’s much larger than as shown embedded in the page.

  13. #13 Anthea Fleming
    March 8, 2010

    Reminds me of a goat I knew – one horn had curled round and was beginning to drill the back of her skull. Her owner contemplated sawing the end off, but the local expert applied a hot iron (electric soldering iron I think) causing the horn tip to divert its course. This did not affect the bone core of the horn. Operation painless, if smelly, but she butted them both just the same.

  14. #14 Rob F
    March 8, 2010

    Folks, you’re looking at a disproof of intelligent design right here. An “intelligent designer” wouldn’t make an organism’s teeth grow into its own skull. Some absolute truths exist, and evolution being a fact is one of them.

  15. #15 doug l
    March 8, 2010

    So…identical skulls or not? Hard to believe that that piercing canine could be so remarkably similar in two different critters, but hey, cameras don’t lie….ahemmmm.
    And I have to wonder if the tooth actually ‘done him in’. I mean, really, how long would it have taken…slow enough for the skull to look like it accommodated the tooth’s rate of growth? It sorta looks like it.
    Oh, and top quality post, Darren. What we all come here for. Thanks for feeding my addiction to quality natural history reportage.

  16. #16 Allen Hazen
    March 8, 2010

    Many years ago I saw a picture of the skull of some rodent whose upper and lower incisors for some reason failed to occlude properly, and so weren’t normally worn down. One tooth (for geometrical reasons I assume a lower, but my memory is pretty hazy) had pierced the skull with (I think the caption said) fatal results.

    (Placental sabretooth catgs– Smilodon &co — had teeth that stopped growing at some point, didn’t they? But I think the sabretooth upper canines of Thylacosmilus were ever-growing. Geometrically they wouldn’t be a danger in this way, but perhaps an old individual could have suffered malnutrition from being unable to open its mouth wide enough to eat comfortably?)

  17. #17 Nathan Myers
    March 8, 2010

    The top two photos really do look like the same specimen, modulo the tusk details. It’s harder to see the similarity in the bottom photo. Unfortunately, this means the specimen was altered. If you were going to replace tusks, why would alter only the “other” ones? Wouldn’t you make the impressive self-impaling tusk replacement too?

    I wish it were real, but I’m not buying it.

  18. #18 Owlmirror
    March 8, 2010

    As an argument against them being the same, I note that the mental (?) foramen on skull 2 certainly appears to be considerably larger than the corresponding one on skull 1.

    But in flipping back and forth between the pictures, I see so many strong similarities that I have to wonder if that apparent difference is just the result of the angle of the photograph.

    =====

    To repeat some of what I wrote previously:

    The Gothenburg Museum of Natural History (Gteborgs Naturhistoriska Museum, GNM) has quite a lot of interesting things online, but you need to know Swedish to search them out. I figured out that the Swedish for “babirusa” is “hjortsvin” (which like the Indonesian means “deer-pig”), and you can search their site to find all of the babirusa skull (and skull fragment) images in their archive. Go to:

    This link for a museum photography archive search.

    In the form section, fill in the entry called “Motiv” with “Hjortsvin”.

    And search (Sök).

    The canine-pierced cranium linked to in the post is towards the end of the search results.

  19. #19 C. P.
    March 9, 2010

    It looks to me like the entire lower jaw was switched sometime between the two photos…

  20. #20 Chris M.
    March 9, 2010

    As far as this being fatal, it does certainly look (in both 1 and 2) like that tusk was long enough to pierce the dura of the brain, which is exceptionally bad news for the babirusa. Alternately, if you’re just putting pressure on the brain (looks like it might be somewhere around the motor cortex, even), a recently clumsy but quite impressive babirusa may have been an easy collector’s target.

    It’s hard to check features with such different lighting and everything, but there is nothing outside the lower jaw to rule out the same skull. The pattern just in front of where the right lower canine passes by the nose looks like one of the most repeated to me, comparing images 2 and 4.

    There’s something different in the edge of the jawbone against the back of the right lower canine, compared to that of #2’s less clean edge. This would make sense with canine replacement or switching out the lower jaw. Looking at the spacing of the small holes Alpha mentions, I’m beginning to think that the lower jaw may not be the original. It’d be nice to get a good, close look at the matching of the tooth wear, though.

  21. #21 Andrea Cau
    March 9, 2010

    In my opinion, the two skulls are the same animal.
    Look at the lateral side of the apex of the tusk, just above the frontal bone: both skulls show the same dark groove-puncture, identical in shape and position: it’s not a morphological feature, but an accident occurred in life. So, they’re the same specimen.

  22. #22 Nathan Myers
    March 9, 2010

    On reflection, I would accept that they just substituted a more photogenic lower jaw without ill intent. They might even have found the correct lower jaw and restored it in place of an ill-fitting previous stand-in.

  23. #23 Dartian
    March 9, 2010

    Darren:

    In other words: could skull 1 merely be skull 2, but fitted out with bigger, meaner-looking lower canines?

    If indeed it’s the same skull in both pictures, there could be an innocuous explanation for replacing the specimen’s lower canines: they might have been stolen by visitors. That kind of thing happens all too frequently in natural history museums, unless specimens are somehow protected (perhaps that’s the reason why ‘skull 1′ seems to have been placed in a glass case). Of course, that wouldn’t excuse making the replacement canines larger than the original were.

  24. #24 Owlmirror
    March 9, 2010

    It looks to me like the entire lower jaw was switched sometime between the two photos…

    <*lightbulb*>

    Of course! That would explain the strange similarities and differences — the similarities are all on top; the differences are on the bottom.

    On reflection, I would accept that they just substituted a more photogenic lower jaw without ill intent. They might even have found the correct lower jaw and restored it in place of an ill-fitting previous stand-in.

    I do note, on looking closely at skull 2 (which I am pretty sure is earlier), that the teeth don’t seem to match up well, for whatever that’s worth.

    On the other hand, I don’t think that a choice to show off by substituting a mandible with larger tusks can be ruled out.

    If indeed it’s the same skull in both pictures, there could be an innocuous explanation for replacing the specimen’s lower canines: they might have been stolen by visitors.

    Or perhaps the older mandible was dropped and shattered, or suffered some other accident.

    And why replace the canines when you can just swap out a mandible? As I noted above, they have *lot* of skulls, and a few separate skull parts.

  25. #25 Andreas Johansson
    March 9, 2010

    I’m sure David M. will be along shortly to tell us that we should just embrace the diacritics and go with “Göteborg”.

    Please don’t. Apart from my general dislike for the replacement of long-standing foreign placenames, hearing anglophones try and pronounce “Göteborg” is painful.

  26. #26 William Miller
    March 9, 2010

    That is absolutely bizarre and very cool.

    I’d read long ago about the babirusa teeth growing back into the head, and I’m glad to see that confirmed.

  27. #27 Jaime A. Headden
    March 9, 2010

    I’m curious, as the comment on self-impalement wasn’t too elabroated on, but does the tusk completely penetrate the frontal, just the frontal sinue, or just the surface of the suprasinusoid frontal bone? If the animal is extremely old, did it actually die of impalement? Finally, as the tusk grew into the skin, would this have not caused sores and infection with a very difficult-to-reach spot to care for, and if so, simple piercing of the skin causes death? In which case, the tusk continuing to grow into the skull would not seem cause for death….

  28. #28 anthrosciguy
    March 9, 2010

    THAT has got to hurt.

  29. #29 Jerzy
    March 9, 2010

    Hmm… I think I remember also there was a skull referred to in some museum in Britain… but the memory can be playing tricks.

  30. #30 John Scanlon FCD
    March 9, 2010

    Look at the two ridges in front of the orbit, in the lacrimal area. In skull 1 they enclose a smallish trapezoidal depression, but in skull 2 the upper ridge is much more arched and does not converge with the lower one, so the space between them is much longer, tapering and open anteriorly. So despite strong similarity, I’m pretty sure they’re different skulls as well as (more obviously) different mandibles.

  31. #31 John Scanlon FCD
    March 9, 2010

    Further to that, the adductor crests on the parietal seem to be closer together in skull 2, maybe forming a sagittal crest posteriorly, and the tusk-hole is adjacent to the crest rather than (as in skull 1) distinctly medial to it.

  32. #32 Henrik Petersson
    March 10, 2010

    Happy to oblige, and great post, Darren!

    As for the question of Gothenburg/Gothemburg, it’s Gothenburg. The misspelling in the post is entirely my fault, because I, mistakenly, wrote “Gothemburg” in my original comment.

  33. #33 Chris
    March 12, 2010

    The colour one looks very much like a cast to me.

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