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Geophagy by yellowstone grizzly bears

Ursus

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Abstract

We documented 12 sites in the Yellowstone ecosystem where grizzly bears (Ursus arctos horribilis) had purposefully consumed soil (an activity known as geophagy). We also documented soil in numerous grizzly bear feces. Geophagy primarily occurred at sites barren of vegetation where surficial geology had been modified by geothermal activity. There was no evidence of ungulate use at most sites. Purposeful consumption of soil by bears peaked first from March to May and again from August to October, synchronous with peaks in consumption of ungulate meat and mushrooms. Geophageous soils were distinguished from ungulate mineral licks and soils in general by exceptionally high concentrations of potassium (K) and high concentrations of magnesium (Mg) and sulphur (S). Our results do not support the hypotheses that bears were consuming soil to detoxify secondary compounds in grazed foliage, as postulated for primates, or to supplement dietary sodium, as known for ungulates. Our results suggest that grizzly bears could have been consuming soil as an anti-diarrheal.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Geophagy by yellowstone grizzly bears
Series title:
Ursus
Volume:
11
Year Published:
1999
Language:
English
Publisher:
International Association for Bear Research and Management
Contributing office(s):
Forest and Rangeland Ecosystem Science Center
Description:
8 p.
First page:
109
Last page:
116
Public Comments:
From a Special Issue: A Selection of Papers from the Eleventh International Conference on Bear Research and Management, Graz, Austria, September 1997, and Gatlinburg, Tennessee, April 1998
Country:
United States
Other Geospatial:
Yellowstone National Park