Consumption of salmon by Alaskan brown bears: a trade-off between nutritional requirements and the risk of infanticide?

摘要: The risk of infanticide may alter foraging decisions made by females, which otherwise would have been based on nutritional requirements and forage quality availability. In systems where meat resources are spatially aggregated in late summer fall, female brown bears ( Ursus arctos) be faced with a trade-off situation. need reproductive females to accumulate adequate fat stores likely result decision frequent salmon streams consume the protein- lipid-rich spawning salmon. contrast, aggregations along create conditions high infanticide. We investigated consumption Admiralty Chichagof Islands Southeast Alaska from 1982 2000 using stable isotope analysis radiotelemetry. While nearly all males (22 23) consumed relatively large amounts (i.e., >10% relative contribution seasonal diet), not n =56) did so. Five 26 for we had data, occupied home ranges that no access thus when they were mated or accompanied young. Of =21), individuals =16) δ15N values indicative consumption. 4 out 16 cubs avoided consuming altogether, other 12, 3 less than mated. For 11 21 data encompassing both states. those altered strategies exhibited significantly lower young mated, while 6 not. Radiotelemetry indicated spring found, average, further away during season compared young, but differ yearlings 2-year-olds. Females lighter indicating choice avoid carries cost translate cub survivorship. role social hierarchy mating history, paternity affecting merit investigation.