Prairie dogs are unexpected killers of ground squirrels

March 24, 2016, 12:07 p.m.
A prairie dog looks out from a burrow
Photo: l i g h t p o e t/Shutterstock

It's not often that a vegetarian mammal goes rogue and murders its competition. In fact, it's never been witnessed until now. Researchers have documented white-tailed prairie dogs killing off ground squirrels — but not to eat them. Just to be rid of them.

Though it's tough to think of these social and adorably rotund rodents taking out other adorable rodents, the act is for a family-oriented reason.

According to National Geographic, "The killers' offspring then live longer, healthier lives — probably because their parents bumped off their competition for food."

The ground squirrels eat the same grasses and prickly pears as the prairie dogs, so by eliminating competition for food, the parents ensure that their offspring have more to eat than they otherwise would. In fact, it seems that this is a primary factor determining the success of the prairie dogs' offspring as well as a longer life for females.

According to the study published in the Proceedings of the Royal Society B, "Females that killed ground squirrels had significantly higher annual and lifetime fitness than non-killers, probably because of decreased interspecific competition for vegetation."

The adult prairie dogs murder because they must. And this action of an herbivorous mammal killing for reasons other than predation is a first for science.

“In my 43 years of research, this is perhaps the most provocative, puzzling, and far-reaching discovery I’ve ever made,” says study co-author John Hoogland of the University of Maryland Center of Environmental Sciences.

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Jaymi Heimbuch is a writer and photographer at Mother Nature Network. Follow her on Twitter, Instagram and Facebook.