What’s the News: Chimpanzees, like people, can “catch” yawns from others. But not all yawns are created equal, it seems; chimps are more likely to catch yawns from a chimp they know than from a stranger, a new study found. (You can see a video of it here.) This supports the idea that it’s empathy—rather than just everybody needing a nap—that makes yawns contagious.

How the Heck:

Two groups of chimps at the Yerkes National Primate Research Center near Atlanta, each with about a dozen adult members, were part of the study. The two groups lived in different large enclosures, and hadn’t seen—much less gotten to know—each other. Chimpanzees are extremely territorial, and a whole lot friendlier to individuals in their own group than to strangers.
The researchers took videos of spontaneous yawns from chimps in each group, as well as videos of the chimps just hanging out in the enclosure. They then played each chimp ...