| Abstract: | Previous results of fecal analysis from the Yellowstone area and the known abilities of grizzly bears Ursus arctos to acquire and digest tissue from vertebrates suggested that grizzlies in this ecosystem obtained substantial energy from ungulates. This issue was addressed using observations from radio-marked grizzly bears, 1977a??1992. Ungulates potentially contributed the majority of energy required for activity during the non-denning season for both adult female and male grizzlies. Most of this energy (95%) was estimated to come from the largest-bodied ungulate species (elk Cervus elaphus, bison Bison bison, and moose Alces alces), with greatest proportional contributions by scavenged adult male bison (16%), scavenged calf and yearling elk (10%) and adult female elk that were killed (8%) or scavenged (8%). Grizzlies acquired 30% of total edibles from ungulates by predation, of which 13% (or 4% of the total) came from predation on elk calves. Most scavenging occurred during the spring and was associated with the abundance and relative availability of different types of carrion. Predation and scavenging did not appear to be compensatory. Rather, total consumption of ungulates varied inversely with consumption of whitebark pine Pinus albicaulis seeds. The relative frequency of predation to scavenging increased with ungulate density. Contrary to previous suppositions, neither total ungulate use nor frequency of predation increased during the study, despite large increases in some ungulate populations. As expected by the identified trade-offs, Yellowstone grizzlies seemed to prey selectively upon moose, probably because of their solitary habits and forested surroundings, but otherwise favored vulnerable smaller-bodied ungulates such as elk calves. No predation on adult bison was observed. |
| Genre: | Article |
| ProdID: | 1015713 |
| Citation Author: | Mattson, D. J. |
| Citation Contributing Office: | Forest and Rangeland Ecosystem Science Center |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 177 |
| Citation Issue: | 1-2 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Biological Conservation |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 17 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | p. 161-177 |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | U.S. Fish and Wildlife Service |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Use of ungulates by Yellowstone grizzly bears Ursus arctos; 1997; Article; Journal; Biological Conservation; Mattson, D. J. |
| Citation Start Page: | 161 |
| Citation Volume: | 81 |
| Citation Year: | 1997 |
| Type: | citation/reference |
| Text: | Use of ungulates by Yellowstone grizzly bears Ursus arctos; 1997; Article; Journal; Biological Conservation; Mattson, D. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1997 00:00 -0600 |
| Publisher: | U.S. Fish and Wildlife Service |
