A fuss over the evolution of males that kill babies has taken a new turn. A broad analysis of mammals says there’s no sign that the danger of infanticide drove species toward monogamy.
That new analysis, in the Nov. 14 Science, examines an evolutionary genealogical tree of 260 species, from lions to mouse lemurs. In 119 of the species, observers report males killing infants they hadn’t sired and thus freeing up the mothers for new matings.
The study tests basic ideas about the evolution of infanticide, but the most contentious result may be its conclusions about what biologists call social monogamy —animals living in pairs (even though there may be a bit of extra-pair mating now and then). In the new analysis, there’s “no evidence” that infanticidal males notably increase the chances of solitary-living ancestors switching to monogamy, says coauthor Dieter Lukas of the University of Cambridge.
