Effects of water enrichment on California sea lions ( Zalophus californianus) housed at the Peoria Zoo.

摘要

Captive animals live in exhibits, which are very different from their native habitats not only in size, but in limited stimulation. When captive animals are not stimulated by their environment, they may become inactive and/or engage in stereotypical behaviors. Zookeepers provide a variety of forms of environmental enrichment as a way of providing stimulation for the captive animal. The California sea lion (Zalophus californianus) is often an animal found in captivity. Although these animals are naturally found in marine environments, the enrichments provided often are not water-based. This study focused on providing water enrichment to two adult captive-born California sea lions, one male and one female, at the Peoria Zoo.At the Peoria Zoo, two California sea lions were housed in an enclosure with three pools and eight areas for haul-out. A baseline period of behavioral observations was conducted for 6 days in May and June, 2008. For 15 days, June-August 2008, data were collected in four trials per day, where each trial was randomly assigned as a control (no water enrichment), oscillating water spray over the pool and center haul-out area (enrichment 1), oscillating water spray over the pool (enrichment 2), or water stream from a hose (enrichment 3).Data were compared between baseline and the enrichment periods by: (1) area chosen in the enclosure, (2) usage of water versus haul-out areas, (3) types of behaviors, (4) activity levels, and (5) rate of stereotypical behavior. In addition, the study examined whether sea lions habituated to the enrichment.Two-way contingency analyses were performed to examine the areas in the enclosure used, specifically whether the location of the water enrichment was avoided, whether water or land was preferred, and whether there were changes in the behavioral repertoire, activity levels, and rate of stereotypical behavior with the addition of water enrichment.Neither the male nor the female sea lions avoided the area with the water enrichment. In the presence of the water enrichments, both animals were more active, engaged in swimming more than resting, and consequently preferred being in the water. Throughout the experiment, the male's swimming behavior was predominately stereotypical lap-swimming, however the rate decreased when the enrichment caused the water to oscillate over the pool and center haul-out area the female had a marked decrease in the rate of her stereotypical lap-swimming in the presence of all three enrichments.The data collected were also analyzed for habituation. The animals in this study did habituate to the enrichments after 34 days. Habituation is a concern for zookeepers and so these three water enrichments should be used in rotation with other forms of enrichment to maintain interest.