Behavior of Hector's Dolphin: Classifying Behavior by Sequence Analysis

Abstract

Behavior sequence analysis was used to classify behavior patterns of Hector's dolphin (Cephalorhynchus hectori) into five categories; feeding, sexual, aggressive, play, and aerial. Feeding behaviors were among the most closely associated behaviors, and were negatively associated with most other behaviors. Bite was closely associated with other apparently aggressive behaviors like tailsplash and chase. Copulations and possible copulations were associated with other behaviors one might have intuitively classified as sexual or social (e.g., belly present, penis out, and body contact). Aerial behaviors were most strongly associated with sexual and aggressive behaviors. Of the two play behaviors, play with weed was most strongly associated with feeding, and bubbleblow was most strongly associated with aggressive and aerial behaviors. I investigated the relationship between the sexual behavior category and social context. The rate of sexual behaviors per individual was highest in groups of 11–15 dolphins and tended to increase after groups came together.