Hormone inspires animal “babysitting”
and World Science staff
Researchers have long studied animal cooperation to understand the evolution of human cooperation. And one arresting example of animal cooperation is animal “babysitting,” cases in which animals decide to care for the offspring of others.
In a new study, scientists researched babysitting among meerkats—small, highly cooperative, mongooses from Southern Africa, often seen standing together in groups on their hind legs, watching for danger.
The researchers’ conclusion: hormones inspire babysitting in male meerkats.
Meerkat families are among the most advanced animal in nature. Members take turns babysitting, foraging for food, watching for danger and even mentoring youngsters, according to some experts.
Anne A. Carlson and colleagues at the University of Cambridge studied wild groups of meerkats and examined the differences between males who decided to babysit for the day, and those who opted to forage instead.
They found that just before a decision to babysit, male meerkats had elevated levels of prolactin, a hormone that in humans has a wide range of functions, including helping to maintain the immune system. In females, prolactin stimulates milk production.
Compared with foragers, “male helpers that decided to babysit for the day had significantly higher levels of prolactin, coupled with lower levels of cortisol,” a stress hormone, the researchers wrote in the March 7 issue of the research journal Hormones and Behavior.
The researchers pointed out that another recent study has found a different hormonal basis for a slightly distinct behavior, pup feeding. Pup feeding takes place when adults give food to youngsters who are following the group on excursions, whereas babysitting occurs when adults stand guard over pups at the home burrow.
The pup feeding behavior was linked to higher levels of cortisol, but not prolactin, the researchers said. They had made that finding earlier with the same group of animals.
“These results lend significant weight to the idea that decisions to help in cooperative vertebrates have a hormonal basis, although different hormones appear to be associated with different types of care,” they wrote.
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