Sex, Age, and Individual Differences in Bottlenose Dolphins (Tursiops truncatus) in Response to Environmental Enrichment

Abstract

Application of environmental enrichment, as a means to successfully decrease undesired behaviors (e.g., stereotypic) and improve animal welfare, has been documented in a variety of zoological species. However, a dearth of empirical evidence exists concerning age, sex, and individual differences in response to various types of enrichment tools and activities in Atlantic bottlenose dolphins (Tursiops truncatus). This study involved a comparative assessment of enrichment participation of three resident, bottlenose dolphin populations, over the course of 17 months, with respect to sex and age class (calf, sub-adult, adult). Enrichment sessions were randomly assigned, conducted, and categorically assessed based on participation during seven, broad based enrichment classes (Object, Ingestible, Human, or a combination of the three). Overall, the proportion of participation in enrichment sessions was high (≥ 0.74), with individual differences in participation noted among the three populations. Sessions involving Humans and/or Ingestible items resulted in a significantly higher mean proportion of participation. Sub-adult and adult males were significantly more likely to participate in enrichment sessions, as well as engage in Human Interaction/Object sessions. Calves participated significantly more than adults or sub-adults across all enrichment classes with no noted differences between males and females. These data can serve as a tool to better understand the intricacies of bottlenose dolphin responses to enrichment in an effort to develop strategic enrichment plans with the goal of improving animal well-being and welfare.