Female vampire bats form strong social bonds with their mothers and daughters as they groom and share regurgitated meals of blood. They also form friendships with less closely related bats. Gerry Carter, post-doctoral fellow at the Smithsonian Tropical Research Institute (STRI), and colleagues discovered that unrelated friends are important backup support when family members go missing.
“Is it better to have a few strong social bonds or a greater number of weaker social ties?” asks Carter. “Theory suggests you should always invest in the cooperative partner that provides the best returns. But clearly, a social animal should not put all its social time and energy in just one relationship, especially in an unpredictable social environment. That’s like putting all your eggs in one basket.”
“Females don’t begin reproducing until they are two years old,” said co-author Gerald Wilkinson professor of biology at the University of Maryland. “They only have one pup per year, so the number of closely related females tends to be low.”
Read more at: https://phys.org/news/2017-05-friends-female-vampire-cope-loss.html#jCp