Comments on: How to Become a Fossil I: Get eaten by a pack of wolves

By: David

David — Thu, 05 Jun 2008 14:28:30 +0000

Holmes, don’t give up yet on the idea of mammoths dancing on the pelvis, and skull. Gary Haynes provides a slightly different perspective re. trampling. He agrees generally with Shipman about most elephants being careful where they tread, but notes exceptions. He says some seem more inclined than others to walk in a straight line, and once they chose a path, nothing deters them–large bones or entire carcasses. . . I knew someone like that in high school.

Reference:
Haynes, G. 1988. Longitudinal studies of African elephant death and bone deposits. Journal of Archaeological Science 15: 131-157.

By: Holmes Semken

Holmes Semken — Tue, 03 Jun 2008 19:07:17 +0000

Pete, I originally broached the idea that the crushed pelvis (and several other bones) could result from being stepped on by a mammoth or mastodon. I now believe the larger bones were broken up because of weathering. They did not get buried as rapidly as either the small or flat bones and, thus, were exposed to the elements for a much longer period of time. All but a few sloth specimens, less ankle and wrist elements, exhibit dry fracture. The pelvis was riddled with closely spaced fracture and probably collapsed largely under its own weight . A bump or two from almost any medium or large animal would speed things along. Dave found an article by Pat Shipman who observed African elephant behavior for a long period of time. Among other things, Shipman documented the demise, decay and breakup of dead African mammals around watering holes. She noted that when large animals encounter large bones, skulls especially she notes (or rocks), they step over or beside, not on, them. Apparently, they avoid them for the same reason that people avoid stepping on rocks if flat ground is available. No sense in risking a strain. I think that Dave put a ‘coup de grace’ on my mammoth theory.

I plan to have another look at the tooth marks on the pelvis Thanks for reminding me.
Holmes

By: Pete Eyheralde

Pete Eyheralde — Fri, 30 May 2008 13:35:32 +0000

Thanks for the info -very interesting! Don mentioned in another post about putting up a sloth diagram with recovered bones shown. The presence or lack of certain bones might be useful in determining possible predator or scavenger ID. Short faced bears are though to have been scavenger/bone crushers, right? Something like that should be easy to see.
I remember working on the sloth pelvis a while back and finding tooth marks that matched closely with fox canines. At the time the idea was being kicked around that the reason the pelvis was so fragmented was that it may have been stepped on by mammoths. Any more thoughts on that?
- Pete

By: David

David — Wed, 28 May 2008 18:30:55 +0000

Pete,

Google “FAUNMAP” and you’ll find several on-line maps showing the distribution of Ice Age mammal fossils being curated in the major museum collections (a limited sample, as Holmes notes). A particularly nice interactive version is at:

http://www.museum.state.il.us/exhibits/larson/ice_age_animals.html

By: Holmes Semken

Holmes Semken — Tue, 27 May 2008 20:52:31 +0000

Pete, There are no large ice-age carnivores curated in museums from Iowa except for the dire wolf. However, discoveries in contiguous states suggest that the short-faced bear, American lion, wolf, jaguar, scimitar cat, saber-tooth cat were present. The American cheetah has been recovered from western South Dakota but I left it off of the list because its known range seems to be to the west of that location. We probably should add paleoindians, documented in Iowa by artifacts and a skeleton in Minnesota, to this list. No evidence of butchering or tools have been recovered from the Tarkio Valley locality. The short-faced bear with its nine foot body probably could take on a sloth solo but the long, strong arm of the sloth certainly was a powerful weapon. Other carnivores, working in tandem, probably could wear a sloth, especially a juvenile, down. We can only speculate on defense mechanisms of a ground sloth.

The paucity of ice-age megamammals from Iowa is taphonomic. Large caves, rare in Iowa, are ideal for the accumulation and preservation of vertebrates. I have collected cave deposits for micromamals for years and never have been ’skunked’ by a cave dig. Little caves will do for these. Large caves abound in Missouri and almost all of the above species are recorded from there. Many are in other surrounding states as well. Moreover, Missouri caves have been extensively investigated, most recently by paleontologists from the Illinois State Museum. Paleontologists interested in ice-age remains flock to caves, especially if they are handy. Thus, distribution maps of fossil mammals also illustrate the distribution of paleontologists or their favored collecting areas.

By: Pete Eyheralde

Pete Eyheralde — Tue, 27 May 2008 18:04:28 +0000

So what big predators are known from Pleistocene Iowa? Wolves for sure. Dire wolves? Any sabertooth cats? What’s big enough to take out a full grown sloth?

By: sloth

sloth — Mon, 26 May 2008 02:49:20 +0000

How to Become a Fossil I: Get eaten by a pack of w……

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