The major cause of infant mortality in some animal species isn't disease or even predators but apparently infanticide inflicted by adult males.

There are numerous reports about animal infanticide, or the killing of infants or the young, that seems ot be prevalent among primates. Most scientists, however, believe this is just deviant behavior. 

Like Us on Facebook

Primatologist Sarah Blaffer Hrdy, however, said infanticide is a product of mammalian evolution. As she's observed these events for decades, she believes this could be a a natural part of mammalian life. Other researchers followed her lead and documented this behavior in hundreds of animal species.

Evolutionary biologists Dieter Lukas and Elise Huchard from the University of Cambridge said they strongly support this infanticide theory based on Hrdy's findings.

Infanticide occurs among mammals where reproduction in a group is dictated or monopolized by a smaller number of males. More often than not, these "alpha males" can't keep up their dominant position because sooner or later, other males will challenge their dominant position.

An unfortunate solution to this is killing off babies fathered by other male challengers so a new dominant male improves his chances of spawning more offspring.

According to Lukas and Huchard, who strongly support Hrdy's claim, nearly half the 260 species they observed had males killing young offspring not related by them. The males killed those babies fathered by challengers to mate with the dead infant's mother, said Huchard.

Mammal species that often practice infanticide are those where females greatly outnumber males. These females can also give birth all year round.

Infanticide is apparently no practiced by mammal species that have seasonal reproduction. Infanticide has been chronicled among animals such as opossums, monkeys and lions.

This study was published in the journal, Science.

TagsSexual Conflict and Evolution: Why Some Mammals Kill Their Babies, Infanticide, why animals kill their young, infanticide kill babies their own kind mammals