Comparing Object Play in Captive and Wild Dolphins

Abstract

Examining the role of play as related to individual and group social development is important to understanding a species. The purpose of our study was to examine whether there is a difference in the frequency of object play exhibited by dolphins from two groups – one captive and one wild. Data were collected with underwater video, with resulting videos event sampled for bouts of play involving various objects used by dolphins. From 159 hr of video data, roughly 102 min featured object play: 75 min of dolphins from RIMS and 26 min for dolphins near Bimini. A total of 304 bouts of object play were documented from or between dolphins at RIMS, while 73 bouts were observed byor between dolphins around Bimini. Juvenile dolphins engaged in solo and mutual play more thantwice that of other aged dolphins from both study groups, although this result was not statistically significant. Similarly, male dolphins at RIMS exhibited object play slightly more than females, though this difference was not significant: at Bimini, male dolphins were not observed to play with objects during interactions with conspecfics (mutual) and engaged in object play about half as oftenas female spotted dolphins. Combining both study groups, dolphins played with about 23 different objects that were grouped into six categories: biological debris, human made objects, inanimate objects, other (e.g., wood, etc), people, and trash. The RIMS dolphins played most with all objects except people while Bimini dolphins interacted with sand more than any other object. Dolphins have been shown to exhibit higher cognitive functions, of which complex play is one example. The role of play in animals is considered important to development and maintenance of social relationships and to learning skills required ultimately for survival.