Paternal care and the development of behavior in the southern grasshopper mouse, Onychomys torridus

Abstract

Litters of southern grasshopper mice ( Onychomys torridus ) were reared by the male and female parents or by the female parent only. All mice were weaned at 25 ± 1 days of age and observed from 30 to 100 days of age in one of four different behavioral tests. These tests included: (a) open-field activity, (b) interspecific aggression toward Mus opponents of the same sex and same approximate age, (c) predatory behavior toward live house crickets, or (d) intraspecific aggression toward Onychomys opponents of the same sex and same approximate age. The presence of the male parent during the preweaning period resulted in a significant increase in the open-field activity of Onychomys females and a significant increase in the aggression of Onychomys males toward Mus opponents. In addition, there was a tendency for subjects reared by the male and female parents to be more efficient in attacking and killing cricket prey. There were no differences between subjects of the two rearing environments with respect to intraspecific aggression. These results suggest that the male parent had an important but selective influence on the behavioral development of Onychomys torridus males and females.