CONSTRAINTS ON FRUGIVORY BY BEARS

摘要: Bears consuming wild fruits for fall energy accumulation are constrained by several factors, including intake rate, the physiological capacity of gastrointestinal tract, and metabolic efficiency gain in body mass. We measured these relationships through foraging feeding trials using captive black bears (Ursus americanus) grizzly arctos). Four fruit types covering a range sizes clustering were offered to determine effect density, size, presentation on rate. Intake rate (in grams per minute) bite rates bites increased cur- vilinearly with increasing density singly spaced fruits. Maximum intakes ranged from 30 g/min 0.5-g berries >200 4.2-g The highest obtained during initial encounter each patch as consumed all visually apparent surface. Bite quickly dropped 15-20% continued within patch. not depressed until fell 100 kg. concluded that large bears, such grizzlies, must depend plants permit or high bush configuration reduce leaf-to-fruit ratios.