Studies On the Behavior of Peromyscus Maniculat Us Gambelii and Peromyscus Californicus Parasiticus
Author: Eisenberg, John F.
Source: Behaviour, Volume 19, Number 3, 1962 , pp. 177-207(31)
Abstract:Peromyscus californicus parasiticus and Peromyscus maniculatus gambelii which inhabit the same macro-environment near Berkeley, California, were the subjects of an analysis of adult behavior patterns. Daily activities of single individuals were observed. Encounters between two animals were staged to determine the basic behavior patterns employed by each species in its intraspecific social behavior. After the various postures had been identified, their frequencies in encounters were found to be influenced by several factors. (1) The sex of the animal under observation. Males exhibit more aggressive patterns and initiate more grooming than do females. (2) The locus of the encounter. An animal introduced into a strange cage exhibits more submission and flight behavior than does the resident. (3) The sex of the animal encountered. A resident male will usually attack another male, but displays upright postures and grooming in response to an introduced female. (4) The physiological condition of the animals participating in the encounter. The chief variables here include the estrous cycle of the females and the breeding condition of the males. In male-male encounters the descended testes are associated with prolonged chases, and aggressive behavior with little grooming. In encounters between males during the non-breeding season, there is less chasing and more mutual grooming. The more complex aspects of social behavior were studied by two other methods: (1) Pairs were observed in order to determine the sexual behavior patterns and the subsequent behavior between the adults and the young. (2) Pairs were established in adjoining cages with removable doors. The pairs were kept separate for two weeks, and then the doors were removed and the subsequent behavior noted. By combining these laboratory data with the field data from several other workers, a picture of the social organization within these two species was constructed. It appears that P. californicus is more strongly territorial, since paired males and females defend the nest site; however, californicus employs a fighting technique involving jumping and avoidance and also exhibits a specific mewing cry which appears to inhibit aggressive behavior of another individual. These patterns may account for the ability of californicus to form bisexual groups of adults with little injury to the participants. P. maniculatus pairs differ in that the female does not defend the nest against intruders unless she is parturient. In the confines of a cage male maniculatus will fight until serious injuries occur. P. californicus with its lower reproductive potential. longer development time for the young, and complex nest, has a more rigid nest defense system and more rigid behavioral controls to regulate aggressive tendencies within the family group. P. maniculatus with its rapid growth rate. larger reproductive potential. and simple nest, has a less rigid social organization and nest site attachment when compared to californicus.
Document Type: Research article
Publication date: 1962-01-01