Eduardo Fernandez-Duque, Yale University – Monogamous Monkeys

It’s Valentine’s Day – an appropriate time to look into the love lives of owl monkeys.

Eduardo Fernandez-Duque, a biological anthropologist at Yale University, is studying pair bonding in mammals.

Eduardo Fernandez-Duque is a biological anthropologist with a general interest in understanding the evolution and maintenance of social systems.  His main research interest is to examine the mechanisms that maintain social monogamy and the role that sexual selection may have had in the evolution of this unusual mating system. He is also motivated to study living primates as an approach to understanding the evolution of human behavior and is particularly interested in male-female relationships, pair bonding and paternal care in humans and non-human primates.

Monogamous Monkeys

The existence of monogamy, pair bonding and the care of infants by males in mammals and primates continue to puzzle evolutionary biologists and anthropologists.

Pregnancy and lactation by females completely condition the amount of investment that can be made by mammalian fathers. Then, why doesn’t a monogamous male mammal seek additional reproductive opportunities? Why does a male mammal invest in young for whom he has no paternity certainty?

The Owl Monkey Project of Argentina has explored these questions since 1996.

Owl monkeys are monogamous and pair bonded. And when an infant is born, the pair shares evenly in the care of the young.

We first examined whether monogamy occurs because of a particular spatial and temporal distribution of food resources. Each monogamous group occupies a small portion of forest with exclusive access to a central portion of it.

Our data suggest that, during the limiting harsh dry season, there may only be enough food for a few animals in this exclusive area, which may result in the formation of monogamous groups.

These findings provided some tentative explanations for social monogamy, but not for the remarkable infant care provided by the male. For this we studied the relationships between pair mates.

We learned that, through aggression and mate guarding, both partners maintain potential competitors at bay and therefore contributing to faithfulness.

But, to fully understand the evolutionary consequences of social monogamy, we needed genetic information on faithfulness and the reproductive success of these bonded pairs.

A genetic study on paternity indicated that males are the biological fathers of the infants they care for, making owl monkeys the first primate for which we have evidence of both social and genetic monogamy.  

Read More: Penn News: Owl Monkeys Don’t Cheat, Penn Study Shows; Intense Fathering Plays a Role