Group composition influences on behavioral sequence patterns of the Guiana dolphin Sotalia guianensis

Abstract

Analysis of behavioral sequences displayed by different individuals can be used to infer individual decisions under diverse conditions. This study investigates whether behavioral transitions and routines differ according to the group composition of Guiana dolphins (Sotalia guianensis). We used the Z-score binomial test to detect significant behavioral transitions from a first-order transition matrix. The directed tree method was used to identify behavioral routines. Solitary individuals presented fewer transitions than heterogeneous groups. More routines were observed for heterogeneous than for homogeneous groups, and fewer routines for solitary individuals. Homogeneous groups maximized routines ending in traveling and milling, while heterogeneous groups presented higher probabilities of socializing. The analyses indicate that subgroups formed during Guiana dolphin fission–fusion events differed in probability of behavioral sequences, reflecting different feeding, resting, and socializing needs at different moments.