Penguins Fool Around More Than We Thought

An enduring and endearing staple of nature shows is the monogamous penguin. The idea that these tuxedo-clad flightless birds mate for life without the occasional affaire de coeur is adorable, but is it true?

“The short answer is no, penguins are not really monogamous,” behavioral ecologist Emma Marks tells Live Science. “Colonial breeders such as penguins may be monogamous, in that they have one mate with whom they nest and raise chicks each season, but that doesn't mean there aren't ‘extracurricular activities going on.”

Those activities include messing around a bit before committing to a mate for the season, hooking up with a lover who is already spoken for, or cheating on a male who spends too much time away from the nest. Sometimes it's not always clear if the male who commits to a female for a season is raising his own chick. In 2018 zoologists at a Utah aquarium observed a cuckolded gentoo penguin male who ended up raising two chicks sired by a different dude. Scientists don't know how often such things happen in nature.

All this hanky-panky notwithstanding, penguins are generally “socially monogamous” by necessity. The unforgiving environment of places like Antarctica requires two committed partners to raise a chick, so penguins will plight their troth, for one season at least, to efficiently divvy up responsibilities like nest maintenance, egg incubation, and bringing in food.

“Social monogamy is a prerequisite," Marks says. “Raising chicks requires a lot of coordination between the two and, if that broke down, breeding would be a failure for the season.”

Parents who make it through a season and successfully breed stand a good chance of pairing up again the following year. Somehow they still find time to play the field.

Photo credit: National University of Singapore