How Do Lemurs Pick Their Friends? Just Like Humans: By Judging Success

A lemur sits in a tree in Antananarivo on July 21, 2014 in Antananarivo, Madagascar.
Photo: David Rogers/Getty Images)

A new study shows that lemur social networks function much the same way that human ones do: the more successful a lemur is at completing a task (getting food out of a box), the more popular that lemur becomes. The study also found that the reverse is true: lemurs who had more friends to begin with were more likely to solve a complex task, implying that social connections influence an animals’ intelligence.

It’s sort of like those age-old adages that your grandma spams your email with (the ones that start with “Choose your friends wisely,” or “A man is known by the company he keeps”), except that this is about lemurs, not humans.


“They [the lemurs] are learning about who is successful and who is not and adjusting their social responses based on this information,” explained Ipek Kulahci, the paper’s lead author and postdoctoral researcher at University College Cork. “We found that lemurs who were frequently observed by others while solving the task to retrieve the food received more affiliative behaviors than they did before they learned, as a result, they became more socially central than they were before the experiment.”

These rules explaining the interplay of social hierarchy and intelligence actually make a ton of evolutionary sense: to be successful, animals have to learn from and about their environment, and then apply this knowledge to things like finding food and avoiding predators. It seems fitting that the smarter an animal is, the more friends it has, and the more friends an animal has, the smarter it is. Still, this is the first time researchers have looked for this connection in the animal world.

The study, published in Current Biology, involved a food reward task in which lemurs learned to retrieve a grape by opening a drawer in a Plexiglas box. The authors found that social interaction and cognitive abilities were “feedback” loops, meaning that intelligence influenced a lemur’s social network, and the size of the network in turn influenced learning.

“Animals learn not only about their physical environment, such as how to obtain food in a situation that they had never encountered before, but they also learn about each other and use this information to make flexible social decisions when forming social relationships,” said Kulahci. “Animals’ cognitive abilities and social behavior are intertwined with each other and, together, influence animals’ decisions in many behavioral contexts such as where and how to forage, with whom to associate, and how to avoid predators or find safety.”



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About the author

Lucas Isakowitz

Lucas is an environmental writer and producer working hard to keep alive the natural curiosity that we all had as children.