FLICKR, TAMBAKO THE JAGUARMale mammals of many species kill the offspring of other males to increase their own chances of successful reproduction. Evolutionary biologists long suspected that this behavior exerted a strong influence on how animal societies were shaped over time. But an analysis of more than 250 different mammalian societies suggests that mammals’ social structure evolved largely independently of infanticide, while finding further evidence that some social factors may have influenced the evolution of the violent behavior. The work was published today (November 13) in Science.
While previous work has largely focused on male infanticide in primates, this new study used a “fresh and broader approach, [going beyond] the limited realms of primatology to analyze data on mammals in general,” primatologist Alan Dixson of the Victoria University of Wellington in New Zealand who was not involved with the study told The Scientist in an e-mail.
Many mammalian mothers undergo a period of postpartum infertility when lactating. In several species, a new male that enters a group at this time is known to kill unrelated infants to end this period, so he can mate with females in the group. Counterstrategies to prevent infanticide range from societies of isolated monogamous pairs, where invading males aren’t an issue, to promiscuous females in loosely-structured groups ...
