Comments on: No left turn http://slothcentral.com/archives/40 A 12,000 year-old mystery in SW Iowa Tue, 20 Apr 2010 02:51:50 -0700 http://wordpress.org/?v=2.8.4 hourly 1 By: David http://slothcentral.com/archives/40/comment-page-1#comment-2236 David Thu, 29 Oct 2009 16:46:09 +0000 http://slothcentral.com/?p=40#comment-2236 Hi Kate, Sounds like a very cool project! Sorry, I had the same trouble getting a copy. I finally turned the problem over to our university librarians and they snagged a xerox from somewhere. It’s a really a terrific paper for ideas. If you want a paper about the decomposition of large mammals--this is it. The author went to Kenya near the end of a drought which killed about 30% of the elephants in the park (~5900) and followed the decomposition of three which had died within hours of his initial observations. As other observers have reported in similar drought situations, the herbivores kept close to the water and soon exhausted food supplies. They ended up dying of malnutrition or related problems, not thirst. The meat supply overwhelmed the local population of vertebrate scavengers. Carrion birds were among the first vertebrate visitors to the carcass. They can cover a lot of ground fast and aren't tied to the water they way other animals are in a drought. They, or any mammal scavengers who happen upon the carcass, are apt to terminate the bloat/putrefaction stage of decomposition, and accelerate the onset of aerobic decay, by piercing the skin, especially that of young animals. The openings are important for the flies. Fly egg-laying is limited to the natural orifices where decomposition gases are being expelled and sufficient moisture is present to allow the eggs to develop, until vertebrates come along and break new openings through the skin. Coe comments on the huge amount of broken chitin that accumulated on the ground around the elephants from the large quantities of insects consumed by birds and insectivores preying on the insects using the carcass. Elephants don't take that much longer to decompose than baby pigs. It took only 20 days for all the soft tissue of a 2-ton elephant to be removed (that's about 1 ton!). Flies took an estimated 3-5%; bacteria took the other 95-97%. The population of microbes is doubling so fast that a 4000# elephant is only going to feed the community a few days longer than a 40# pig! In a drought the flood of meat is apt to overwhelm the population of local vertebrate scavengers. They obviously can't reproduce quickly enough to take advantage of the surplus, nor will many be recruited from the outside to join at the dinner table. In a 1960-61 drought in Nairobi National Park, less than 10% of the ~5,000 carcasses were utilized by vertebrate scavengers in the soft tissue stage. However, the dry bones will be chewed and scattered for many months after the soft tissue is gone ("virtually none" of the skeletons of the large mammals remained intact. He concludes, "only perhaps those few animals that died wholly or partly in contact with water would have stood more than a minor chance of being buried and subsequently fossilized." Try your librarians. If that doesn't work let me know and I'll just xerox this myself and send it. good luck. D Hi Kate, Sounds like a very cool project! Sorry, I had the same trouble getting a copy. I finally turned the problem over to our university librarians and they snagged a xerox from somewhere. It’s a really a terrific paper for ideas. If you want a paper about the decomposition of large mammals–this is it. The author went to Kenya near the end of a drought which killed about 30% of the elephants in the park (~5900) and followed the decomposition of three which had died within hours of his initial observations. As other observers have reported in similar drought situations, the herbivores kept close to the water and soon exhausted food supplies. They ended up dying of malnutrition or related problems, not thirst. The meat supply overwhelmed the local population of vertebrate scavengers.

Carrion birds were among the first vertebrate visitors to the carcass. They can cover a lot of ground fast and aren’t tied to the water they way other animals are in a drought. They, or any mammal scavengers who happen upon the carcass, are apt to terminate the bloat/putrefaction stage of decomposition, and accelerate the onset of aerobic decay, by piercing the skin, especially that of young animals. The openings are important for the flies. Fly egg-laying is limited to the natural orifices where decomposition gases are being expelled and sufficient moisture is present to allow the eggs to develop, until vertebrates come along and break new openings through the skin.

Coe comments on the huge amount of broken chitin that accumulated on the ground around the elephants from the large quantities of insects consumed by birds and insectivores preying on the insects using the carcass.

Elephants don’t take that much longer to decompose than baby pigs. It took only 20 days for all the soft tissue of a 2-ton elephant to be removed (that’s about 1 ton!). Flies took an estimated 3-5%; bacteria took the other 95-97%. The population of microbes is doubling so fast that a 4000# elephant is only going to feed the community a few days longer than a 40# pig!

In a drought the flood of meat is apt to overwhelm the population of local vertebrate scavengers. They obviously can’t reproduce quickly enough to take advantage of the surplus, nor will many be recruited from the outside to join at the dinner table. In a 1960-61 drought in Nairobi National Park, less than 10% of the ~5,000 carcasses were utilized by vertebrate scavengers in the soft tissue stage. However, the dry bones will be chewed and scattered for many months after the soft tissue is gone (”virtually none” of the skeletons of the large mammals remained intact. He concludes, “only perhaps those few animals that died wholly or partly in contact with water would have stood more than a minor chance of being buried and subsequently fossilized.”

Try your librarians. If that doesn’t work let me know and I’ll just xerox this myself and send it. good luck. D

]]> By: Kate Harding http://slothcentral.com/archives/40/comment-page-1#comment-2233 Kate Harding Tue, 27 Oct 2009 14:19:14 +0000 http://slothcentral.com/?p=40#comment-2233 Dear Dave, I'm very grateful to you for the African Elephant information you have featured here. The reason being that I am looking onto large animal decomposition - from point of death to diagenesis - for a TV idea I am developing. After lots of searching and imminent deadlines, I still haven't been able to find a copy of Coe's 1978. The decomposition of elephant carcasses in the Tsavo (East) National Park, Kenya. article. Our local university library doesn't stock the journal either. Do you happen to know where I could find a copy? Or might you be able to email me a pdf / word doc? Thank you so much. Kate Harding Dear Dave,

I’m very grateful to you for the African Elephant information you have featured here.

The reason being that I am looking onto large animal decomposition – from point of death to diagenesis – for a TV idea I am developing. After lots of searching and imminent deadlines, I still haven’t been able to find a copy of Coe’s 1978. The decomposition of elephant carcasses in the Tsavo (East) National Park, Kenya. article.

Our local university library doesn’t stock the journal either. Do you happen to know where I could find a copy? Or might you be able to email me a pdf / word doc?

Thank you so much.
Kate Harding

]]> By: Robert K. McAfee http://slothcentral.com/archives/40/comment-page-1#comment-191 Robert K. McAfee Sat, 20 Sep 2008 04:21:48 +0000 http://slothcentral.com/?p=40#comment-191 Strange. I've felt at times in the past that I ended up seeing more bones from the left than right sides when I'm in museum collections. But that in itself is an odd preservational bias as I'm looking for the best and most complete elements, which end being lefts. Strange. I’ve felt at times in the past that I ended up seeing more bones from the left than right sides when I’m in museum collections. But that in itself is an odd preservational bias as I’m looking for the best and most complete elements, which end being lefts.

]]> By: David http://slothcentral.com/archives/40/comment-page-1#comment-178 David Thu, 11 Sep 2008 22:30:04 +0000 http://slothcentral.com/?p=40#comment-178 Hi Pete, I'm working on a post about Jim Huber's preliminary pollen analysis right now, but since it's a sample from the sediments around the bones, it's an average and not a snapshot from the time of death. Plant phytolyths are a good idea. No one has looked. I don't know how firmly they get embedded--if they are semi-permanent or transitory. Diatoms might show seasonal differences but I gather any that end up in the bones are there permanently and could have found there way there any time while the sloth was alive (assuming we could prove they got there in life and weren't post-mortem). Art Bettis at the UI has a grad student doing a preliminary screening of the sediments for other microfossils. I'm hoping some insects show up. Then we'll have to figure out where insects might have settled while they were doing their grisly decomposing business and might have been preserved. Forensic scientists have a long history of using insects to estimate time of death. Something I'll want to write about if Art finds any. Hi Pete, I’m working on a post about Jim Huber’s preliminary pollen analysis right now, but since it’s a sample from the sediments around the bones, it’s an average and not a snapshot from the time of death. Plant phytolyths are a good idea. No one has looked. I don’t know how firmly they get embedded–if they are semi-permanent or transitory. Diatoms might show seasonal differences but I gather any that end up in the bones are there permanently and could have found there way there any time while the sloth was alive (assuming we could prove they got there in life and weren’t post-mortem). Art Bettis at the UI has a grad student doing a preliminary screening of the sediments for other microfossils. I’m hoping some insects show up. Then we’ll have to figure out where insects might have settled while they were doing their grisly decomposing business and might have been preserved. Forensic scientists have a long history of using insects to estimate time of death. Something I’ll want to write about if Art finds any.

]]> By: Pete Eyheralde http://slothcentral.com/archives/40/comment-page-1#comment-175 Pete Eyheralde Wed, 10 Sep 2008 16:08:37 +0000 http://slothcentral.com/?p=40#comment-175 Pollen samples from the soil around the bones might give info on the season of death. Any plant debris in the teeth? Or if it died in the water -could it have ingested something microscopic that would give clues about what time of year it died? Wasn't there something a while back about diatoms in the bones? Pollen samples from the soil around the bones might give info on the season of death. Any plant debris in the teeth? Or if it died in the water -could it have ingested something microscopic that would give clues about what time of year it died? Wasn’t there something a while back about diatoms in the bones?

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