Comments on: If you are what you eat http://slothcentral.com/archives/45 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/45/comment-page-1#comment-298 David Sun, 16 Nov 2008 20:28:14 +0000 http://slothcentral.com/?p=45#comment-298 Rob--I found the source of my confusion about Shasta’s diet. Martin et al. (1961) looked at the pollen alone in the dung and found some things that most other herbivores shun (e.g. creosote bush and cactus). They concluded that Shasta occupied a unique niche that no other North American animal filled before or since. They discuss the possibility of the pollen coming from non-dietary plants landing on the leaves of ingested plants and confounding the results, but apparently it was a bigger factor than they assumed. I’m kind of pleased about the change in view. This sloth business wouldn’t be half so interesting if their success could be explained as easily as their occupying a unique diet niche. Reference: Martin P.S., Sabels, B.E. and Shutler, D. Jr. 1961. Rampart cave coprolite and ecology of the Shasta ground sloth. American Journal of Science 259: 102-127. Rob–I found the source of my confusion about Shasta’s diet. Martin et al. (1961) looked at the pollen alone in the dung and found some things that most other herbivores shun (e.g. creosote bush and cactus). They concluded that Shasta occupied a unique niche that no other North American animal filled before or since. They discuss the possibility of the pollen coming from non-dietary plants landing on the leaves of ingested plants and confounding the results, but apparently it was a bigger factor than they assumed. I’m kind of pleased about the change in view. This sloth business wouldn’t be half so interesting if their success could be explained as easily as their occupying a unique diet niche.

Reference: Martin P.S., Sabels, B.E. and Shutler, D. Jr. 1961. Rampart cave coprolite and ecology of the Shasta ground sloth. American Journal of Science 259: 102-127.

]]> By: David http://slothcentral.com/archives/45/comment-page-1#comment-253 David Fri, 07 Nov 2008 17:37:54 +0000 http://slothcentral.com/?p=45#comment-253 Hi Rob--Eating everything and anything was long my impression too, to tell you the truth. I’ve been searching for the source of that (mis)information and haven’t found it yet. Hanson (1978) identified the remains of 72 different genera in the 500-odd poop-balls he analyzed from Rampart Cave, but the plants I cited in my post represent 90% of what he found. I also recollect seeing a plant list somewhere that included some species indigestible to most other mammals, but Hanson says Shasta's tastes were pretty tame and comparable to other large mammals, i.e. they ate what was available and there’s no sign they found a special niche eating the ugly stuff. He suggests that lacking front teeth they couldn’t be picky eaters and accidentally ingested some of the plants on his list while they were gathering mouthfuls of the favored species. Poinar et al. (1998) sequenced the DNA in poop from Gypsum Cave and found some of the same things, and nothing that conflicts with Hansen’s conclusions. He added capers and mustard to the list of common plants, suggesting they were so easily digested that perhaps nothing survived to be recognizeable by Hanson’s macroscopic technique. The bottomline remains—this is a sloth that would have enjoyed any salad bar in town--especially the all-you-can-eat kind. Hanson, R.M. 1978. Shasta ground sloth food habits, Rampart Cave, Arizona. Paleobiology 4: 302-319. Poinar, H.N., Hofreiter M., Spaulding, W.G., Martin, P.S., Stankiewicz, B.A., Bland, H., Evershed, R.P., Possnert, G., and Paabo, S. 1998. Molecular coproscopy: dung and diet of the extinct ground sloth Northrotheriops shastensis. Science 281: 402-406. Hi Rob–Eating everything and anything was long my impression too, to tell you the truth. I’ve been searching for the source of that (mis)information and haven’t found it yet. Hanson (1978) identified the remains of 72 different genera in the 500-odd poop-balls he analyzed from Rampart Cave, but the plants I cited in my post represent 90% of what he found. I also recollect seeing a plant list somewhere that included some species indigestible to most other mammals, but Hanson says Shasta’s tastes were pretty tame and comparable to other large mammals, i.e. they ate what was available and there’s no sign they found a special niche eating the ugly stuff. He suggests that lacking front teeth they couldn’t be picky eaters and accidentally ingested some of the plants on his list while they were gathering mouthfuls of the favored species. Poinar et al. (1998) sequenced the DNA in poop from Gypsum Cave and found some of the same things, and nothing that conflicts with Hansen’s conclusions. He added capers and mustard to the list of common plants, suggesting they were so easily digested that perhaps nothing survived to be recognizeable by Hanson’s macroscopic technique. The bottomline remains—this is a sloth that would have enjoyed any salad bar in town–especially the all-you-can-eat kind.

Hanson, R.M. 1978. Shasta ground sloth food habits, Rampart Cave, Arizona. Paleobiology 4: 302-319.

Poinar, H.N., Hofreiter M., Spaulding, W.G., Martin, P.S., Stankiewicz, B.A., Bland, H., Evershed, R.P., Possnert, G., and Paabo, S. 1998. Molecular coproscopy: dung and diet of the extinct ground sloth Northrotheriops shastensis. Science 281: 402-406.

]]> By: Robert K. McAfee http://slothcentral.com/archives/45/comment-page-1#comment-233 Robert K. McAfee Fri, 24 Oct 2008 15:50:44 +0000 http://slothcentral.com/?p=45#comment-233 My favorite bit of info relating to all the Shasta dung balls is that the analyses show Nothrotheriops to be a bit of a nomad that wandered around and ate pretty much whatever plant matter it came in contact with. Supposedly there are some dung balls for Mylodon darwini from South America but I don't believe there have been any studies of content as in depth as those for Nothrotheriops. A pity as it would be nice to compare the diets, even if they are from two widely separated sloths, both taxonomically and geographically. My favorite bit of info relating to all the Shasta dung balls is that the analyses show Nothrotheriops to be a bit of a nomad that wandered around and ate pretty much whatever plant matter it came in contact with.

Supposedly there are some dung balls for Mylodon darwini from South America but I don’t believe there have been any studies of content as in depth as those for Nothrotheriops. A pity as it would be nice to compare the diets, even if they are from two widely separated sloths, both taxonomically and geographically.

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