Baby Monkeys That Are In Danger Of Being Killed By Adult Males Grow Fast

Baby monkeys sprint through childhood so that they are not killed by male adult monkeys, says a new study on wild ursine colobus monkeys, according to researchers at the University of Ontario.

They studied nine groups of wild ursine colobus monkeys from 2007 to 2014.

"Infanticide occurs in many animals, including carnivores like lions and bears, rodents like mice, and in primates," said lead researcher Iulia Bădescu, a Ph.D. candidate in evolutionary anthropology at the University of Toronto.

"Typically, an adult male kills an infant sired by another male so that he can mate with the mother and sire his own infants with her," she explained.

Bădescu's group examined the adult ursine colobus monkeys and noted the changes in their fur, according to researchers. The colobus babies are born with white fur that becomes grey after a few weeks, then black and then white again between two and five months.

The change in fur color of babies at risk was observed to be changing quickly from white to grey to black and white.

"We found that infants facing a greater risk of infanticide developed faster than infants facing lesser risk," said co-researcher Pascale Sicotte of the Department of Anthropology and Archaeology at the University of Calgary.

Earlier, it was seen that babies that were in groups with many adult males always faced greater danger of getting killed.

Hence, the mothers of such babies tended to put in more energy and resources to speed up their development.

"We know that infanticide is the result of an evolutionary arms race, where males compete with each other for reproduction and try to influence females in mating with them," Sicotte added. "In species where it happens more often, it can certainly influence the nature of the social relationships between males, as well as between males and females."

"Infant males are at greater risk of infanticidal attacks because killing a male infant not only gives reproductive access to the mother, but also eliminates a future sexual rival for the infanticidal male and his future offspring," Bădescu explained.

The findings are published in the journal Animal Behaviour.