Comparative paternal and infanticidal behavior of sympatric white-footed mice (Peromyscus leucopus noveboracensis) and deermice (P. maniculatus nubiterrae)

We studied parental and infanticidal behavior in the field andlaboratory in two ecologically equivalent and sympatric congeners,white-footed mice, Peromyscus leucopus noveboracensis, and deermice,P. maniculatus nubiterrae. Despite their close phylogeneticrelationship and ecological similarity, various aspects of parentaland nesting behavior of the two species were significantly different.P. maniculatus males were more paternal than were P. leucopusmales in that they retrieved pups, nested with pregnant femalesand females with newborn pups, and formed longer associationswith females than did P. leucopus males. Thus, P. m. nubiterraeexhibited more pair-bonding (monogamous) characteristics thandid either P. leucopus or P. m. bairdi, as reported in otherstudies. The behavioral differences may represent the differentevolutionary history of the three subspecies. Infanticidal behavior,however, was similar in both species. Dispersing and unmatedmales killed strange pups placed in experimental test chambersin the field, whereas mated males did not kill pups within theirown home ranges. Resident females of both species were moreinfanticidal than were males, killing pups in 90% of the trials.The results support the sexual selection and resource competitionhypotheses for male and female infanticide, respectively. BehavEcol 1991; 2: 38-45]