Lemurs Living in Larger Groups Display Social Smarts: Different Types of Intelligence

There are all different kinds of intelligence--and social intelligence is one of them. A charismatic individual knows exactly how to act around others, navigating social cues that others might miss. Now, scientists have discovered that it's not just humans that demonstrate this particular intelligence. Lemurs can also display social smarts.

In order to examine lemurs that live in larger social groups with ones that didn't, researchers conducted several experiments. Working with six different species of lemurs living at the Duke Lemur Center, the scientists tested 60 individuals to see if they would be more likely to steal a piece of food if a human wasn't watching them. The general idea was that a lemur that was more socially conscious wouldn't steal in front of the person.

In one test, a pair of human testers sat with two plates of food. One person faced the plate and the lemur entering the room. The other had his back turned. In the other test, testers sat in profile, either facing toward or away from the plate. In a third test, they wore a black band either over their eyes or over their mouths and both faced the plates and the lemurs.

So how did these lemurs act? The ones from larger social groups, like the ringtailed lemur, were far more sensitive to social cues. These creatures live in groups of about 15 in the wild. They were more hesitant to grab food from a human who was watching. In contrast, lemurs from smaller groups, like the mongoose lemur, were less sensitive to these social cues. These lemurs live in groups that usually only consist of two or three individuals. None of the lemurs really understood the significance of the blindfold.

The findings reveal the type of intelligence that these creatures possess. In addition, the work is the first to test the relationship between group size and social intelligence across multiple species. It also shows that intelligence based solely on brain size may not hold up--especially when it comes to different kinds of intelligence.

The findings are published in the journal PLOS One.