The findings of a recent study have revealed that many male adult mammals practice infanticide or kill their own young ones. In the most thorough study till date on the practice of infanticide in mammals, 260 species were studied and it was found that killing younger ones of their own species was common among nearly 119 species of animals.
That means nearly half the animals being observed kill their own young ones. The rate of killing young ones was the highest among Chacma baboons found in southern Africa- with nearly half of their young ones being slaughtered by older males.
The study was carried out by Elise Huchard from the National Center for Scientific Research’s Center for Evolutionary and Functional Ecology and Dieter Lukas from the University of Cambridge. Together they wanted to establish a correlation between mammals and the practice of killing young ones of their own species among mammals and also identifying the factors responsible for it. In their attempt to do so, they compared several factors in unison to develop a pattern- they studied the social structure among the species under observation to their mating behavior.
Huchard told Reuters that killing their own young ones was a part of ‘a sexual strategy’ by these males- directed towards making the mother available for sexual activity once again. This he concluded because the practice was not common in species which were monogamous or among animals who do not stay in groups. “Infanticide is probably the most extreme manifestation of sexual conflict in mammals, with a major fitness cost for mothers who lose their offspring, in which they have already invested lots of energy,” shares Huchard.
Furthermore, infanticide was not prevalent among animals which had a distinct mating season, “where it would be of little advantage to the males, who would have to wait until the next season regardless.”
Lukas also said that females try to countering the “infanticide behavior” by mating with more males. This makes the males unsure if the young ones are theirs. Apparently, as Huchard explains, “Males stop killing offspring if there is a risk that the offspring might be their own.”
The males of species which practice infanticide were also seen to have larger testes than others- perhaps to make sure that they will always have an adequate sperm count when they mate. This has been described in the report as the counter strategy by the male of species to the female counter-strategy by the authors. They also observed that the practice of infanticide is not a male preserve and females were likely to do so as well though the incidence is much lower among them.