Social behavior and group formation in the coypus (Myocastor coypus) in the Argentinean pampas

GUICHÓN ML, M BORGNIA, C FERNÁNDEZ RIGHI, G CASSINI Y MH CASSINI

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Año: 2003 vol. 84 p. 254 - 262

0022-2372

This study presents the first description of social behavior and structure in native populationsof the coypu (Myocastor coypus). Data from behavioral observations and trappingwere used to describe group composition and behavior at 3 study areas in east-centralArgentina in 1999–2000. Seven groups were described (11 coypus/group 6 1.5 SE). Groupswere characterized by several adult and subadult females, 1 dominant male, several adultand subadult males, and a variable number of juveniles. Subgroups (mainly composed ofjuveniles and small adult males) were also identified within some groups. Group fidelitywas relatively high. Amicable interactions and cooperative behaviors such as nursing ingroups, allogrooming, and alarm calls occurred within groups. Agonistic interactions andmarking behavior were rare but suggested that the largest male was socially dominant. Thisstudy confirms gregarious habits and a polygynous mating system for the species andprovides the first report of the existence of some cooperative behaviors.