Tolerating aggression may just be in your genes, reveal scientists.
"The ability to tolerate aggression is passed on across generations; there is genetic variation in the ability to tolerate aggression," said Daniel T. Blumstein, professor and chair of ecology and evolutionary biology at UCLA.
Blumstein and his colleagues studied four groups of yellow-bellied marmots, which are related to squirrels, over six years in the Rocky Mountains of Colorado. Each group included 15 to 30 marmots.
"We are gaining a novel insight into the importance of tolerating aggressive interactions. Those relationships are important for social stability and reproductive success. I believe these ideas are generalizable well beyond marmots," Blumstein said.
Amanda Lea, a former UCLA honours student, spent two summers observing the marmots for four hours a day and analyzing their behavior - from far enough away not to affect it. She can tell the marmots apart.
"We found that having many friendly interactions gave marmots fitness benefits - these marmots reproduced more. But surprisingly, we found that marmots embedded in a network of unfriendly interactions also showed higher fitness levels," Lea said.
"Over a lifetime, a marmot that is very social will have more offspring than a less social one. But surprisingly, so will a marmot that is getting picked on frequently," she added.
"The family unit is important, even if their interactions are not always nice," Blumstein said of the finding.
Genetic factors account for some 10 percent of the differences among marmots, while about 20 percent of the variation is due to the social environment, they calculated.
"There is a genetic component to certain social behaviors, and we have quantified that," Blumstein said.
Social network statistics can be a useful way to study a variety of animals and understand social evolution. Blumstein said.
"We found that direct measures were heritable and indirect measures were not; we expected this. However, within these direct relationships, you might expect that things I do to you, things I have control over, would have significant heritability, but what we found is the opposite: the ability to tolerate aggression is heritable, and we found that fascinating," he said.
"Tolerating aggression is, surprisingly, very important in marmots and perhaps in other species."
The research is currently published in the online early edition of the journal Proceedings of the National Academy of Sciences.