Researchers Dieter Lukas and Elise Huchard have explained why there is a high rate of infanticide, or the killing of others' or one's young, among many mammalian species, Uncover Michigan reported.
Lukas, a zoologist at the University of Cambridge, and Huchard, a behavioral ecologist with the French National Centre for Scientific Research, wanted to study the actions of mammals, their social structure and mating behavior. Closer analysis, however, revealed a pattern of behavior, specifically among male mammals.
After careful examination of the observational studies of 260 species of mammals, the team discovered that 119 of the species practiced in infanticide.
The researchers concluded that among mammals, the South African Chacma Baboon was shown to kill almost half of its own young, and, as a whole, the males of the species commit infanticide more than the females. After further analysis, it was seen that males perform the act when there are many dominating males in their communities and fewer females.
Huchard explained that the behavior was a form of "sexual strategy." Males would choose to kill the young of other males, leaving the mothers distraught at having lost their offspring. The female would, therefore, be available for mating, though this time with a different male.
They called it "the most extreme manifestation of sexual conflict in mammals."
In their study, Huchard and Lukas noted that the behavior was not present in other species who practice monogamy or those that live alone. The behavior is also not present in those who have a set mating season, as the males see no sense in killing the young of others when the females are not immediately ready to mate.
Lukas, however, noted that to prevent such behavior from their counterparts, some females engage in promiscuity and choose to mate with more males, leaving them unsure as to which child is theirs and preventing the deaths of their young.
Over the years there have been numerous theories as to why infanticide occurs in the wild, according to the Smithsonian.
Researchers have come up with explanations, such as the possibility that the other members of the species see the newborns as exploiting or competing for the few resources available, while some have considered it as a purely pathological nature. Some researchers have theorized that it was related to a species' need to reproduce.
Sarah Hrdy, an anthropologist at the University of California at Davis, first proposed the idea in the 1970s, claiming that "infanticide can be an evolved reproductive strategy in males, and sometimes females."
Lukas and Huchard's study have now served to expound on the theory.
The pair's study came about as they were interested in seeing how mammalian infanticide has evolved in the past 160 million years of evolution, according to The New York Times.
"When we started, we weren't sure if infanticide was present in some ancestral mammal and is just more pronounced in some species and is lost in other species. Or maybe it just evolved in those species where the conditions were right," Lukas said.
Their research has since revealed the latter. Common ancestors of various mammal species were not seen to engage in the behavior, but have evolved throughout the years in separate lineages.
Lukas and Huchard's study was officially published in Science on Friday.
