Functional aspects of maternal aggression in mammals

Evidence from several species of mammals suggests that the observed increase in female aggressiveness during lactation is aimed at protecting offspring from conspecifics. Whereas in rodents maternal aggression seems to constitute a deterrent against infanticidal behavior by adult males and females, in pinnipeds and primates its most likely function is to protect infants from general harassment by other individuals. Maternal aggression may also be involved in mate selection and function as a spacing mechanism. As an offspring defence behavior, maternal aggression can be considered a form of parental investment. As such, predictions can be made about its intensity in relation to the net effects it has on parental fitness. The functional aspects of maternal aggression suggest that this behavior should be analyzed in relation to other patterns of maternal care and investment in the offspring.