Social animals have more social smarts

Jun 26, 2013
In a series of stills taken from videotaped experiments, Duke undergraduates Joel Bray (left) and Aaron Sandel test a ringtailed lemur's (Lemur catta) willingness to take food from a watched or unwatched plate. Credit: Evan MacLean, Duke

Lemurs from species that hang out in big tribes are more likely to steal food behind your back instead of in front of your face.

This behavior suggests that primates who live in larger social groups tend to have more "social intelligence," a new study shows. The results appear June 27 in PLOS ONE.

A Duke University experiment tested whether living in larger social networks directly relates to higher social abilities in animals. Working with six different species of lemurs living at the Duke Lemur Center, a team of undergraduate researchers tested 60 individuals to see if they would be more likely to steal a piece of food if a human wasn't watching them.

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 or her back turned. In a second, testers sat in profile, facing toward or away from the plate. In a third, they wore a black band either over their eyes or over their mouths and both faced the plates and lemurs.

As the lemurs jumped onto the table where the plates were and decided which bit of food to grab, the ones from large social groups, like the ringtailed lemur (Lemur catta), were evidently more sensitive to that a person might be watching, said Evan MacLean, a research scientist in the Department Of Evolutionary Anthropology who led the research team. Lemurs from small-group species, like the mongoose lemur (Eulemur mongoz), were less sensitive to the humans' orientation.

Few of the lemurs apparently understood the significance of a blindfold.

The work is the first to test the relationship between group size and social intelligence across multiple species. The findings support the " hypothesis," which suggests that living in large social networks drove the evolution of complex in primates, including humans, MacLean said.

Behavioral experiments are critical to test the idea because assumptions about intelligence based solely on brain size may not hold up, he said. Indeed, this study found that some species had evolved more social smarts without increasing the size of their brains.

Explore further: Personality test finds some mouse lemurs shy, others bold

More information: "Group Size Predicts Social But Not Nonsocial Cognition in Lemurs," Evan MacLean, Aaron Sandel, Joel Bray, Ricki Oldenkamp, Rachna Reddy and Brian Hare. PLOS ONE, June 27, 2013. dx.plos.org/10.1371/journal.pone.0066359

Related Stories

Personality test finds some mouse lemurs shy, others bold

Jun 18, 2013

Anyone who has ever owned a pet will tell you that it has a unique personality. Yet only in the last 10 years has the study of animal personality started to gain ground with behavioral ecologists, said Jennifer ...

Primate hibernation more common than previously thought

May 02, 2013

(Phys.org) —Until recently, the only primate known to hibernate as a survival strategy was a creature called the western fat-tailed dwarf lemur, a tropical tree-dweller from the African island of Madagascar.

Lemurs the world's most threatened mammal: study

Jul 14, 2012

Lemurs, the furry apes brought to fame by the Disney animation film "Madagascar", are the most endangered mammals on Earth, an International Union for Conservation of Nature conference found.

Madagascar lemurs top endangered primates list

Oct 15, 2012

In the hit cartoon film "Madagascar", the island's lemurs are a lovable bunch of extroverts, but they are also among the world's most threatened primates, conservationists warned on Monday.

Recommended for you

Orchid named after UC Riverside researcher

13 hours ago

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

15 hours ago

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

15 hours ago

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...