Foraging devices as enrichment in captive walruses (Odobenus rosmarus).

Stereotypies in captive animals are typically defined as repetitive, invariant behavioral patterns with no obvious goal or function. They are often attributed to boredom or fear and treated by introducing occupational stimuli. The present work on captive walruses examined the relationship between walrus stereotypies and species-typical foraging behaviors engaged in by their wild counterparts. Two types of walrus stereotypies were studied: (a) patterned swimming around their pool, or (b) repetitive sucking of some item, typically their own flipper. We tested two enrichment devices under filled and empty conditions: large foam/rubber mats and hollow boomer balls, both with multiple holes in them. Both devices were designed to stimulate the use of flippers, vibrissae, and mouth suctioning of small food in the devices. Walruses in the devices with food conditions increased locomotion and device contact and decreased engaging in stereotypies. We conclude: (1) daily stereotypies in these captive walruses are based on incomplete behavioral foraging "loops" (2) providing stimuli supporting completed foraging sequences can reduce stereotypies and increase active foraging components.