We know that the fetal environment may generate profound, lifelong effects. We studied the effects of litter-sex ratio on female yellow-bellied marmots. We found that females growing up in male-biased litters, a situation which exposes them to male hormones during development, were more likely to initiate play and allogrooming as pups, but as yearlings were more likely to engage in estrogen-mediated sociopositive behavior. We suspect that this worked by making these “marmot tom-boys” engage in more exploration, a behavior that led to more encounters with others as well as increasing the likelihood of dispersal. Our results further illustrate the diverse consequences that endocrine disruptors might have in wild animals.
The BBC (along with some other news sources) picked up the story.
Read the BBC article here.