Monkey See, Monkey Do?

Q: If a human yawns in front of a monkey, will the monkey yawn?
Amanda, Spokane, Washington

A: A days-old macaque monkey shifts in human hands, and gazes up, around, down and finally notices the blue-suited human in front of her. The human, close enough to spit on, sticks his tongue out at the monkey, repeatedly. The baby monkey fixes her large, brown eyes on the human. After the seventh such tongue-sticking out, the baby flips her hand over her big, pink ear, ducks her head down, then up. She looks squarely at the human, and sticks her own tongue out — and yawns.

If a human yawns in front of a baby monkey, she might, indeed imitate the human yawn by yawning also.

Italian researchers (Pier Ferrari et al) tested 21 baby macaque monkeys, and found that, after age day 3, the monkeys imitated humans smacking their lips, opening their mouths and sticking out their tongues. These are all facial expressions common among monkeys. The babies quit imitating humans at age 14 days, but they may continue to imitate monkeys much longer.

Baby monkeys, like baby humans, can't see their own face so they customarily imitate their mother's expressions, probably to learn correct social behavior. Human babies imitate in this fashion until they are about three months old, chimp babies until two months of age and monkeys at least until two weeks.

The reader, however, asked about yawning, not merely imitating, which thickens the plot. Yawning can be a group activity. It's contagious among primates. About 60% of humans catch yawns from each other, and about 33% of chimpanzees do, too. Even monkeys catch yawns from each other, as Paukner et al determined by having a group of stumptail macaques monkeys watch a video of other yawning monkeys.

Humans can catch yawns from chimps, and chimps catch yawns from humans. Can monkeys catch yawns from humans? I find no supporting evidence upon searching the literature. But they might.

By the way, when baby monkeys imitate an action, mirror-neuron paths in their brains become active. The same holds true for human babies. This means we trace imitation brain hardware — mirror neurons — back to before monkey ancestors split off from the ape lineage. Our ancestors probably began learning by imitating about 25 million years ago.

Further Reading:

Proved: monkey see, monkey do, New Scientist, September 2006 (research from University of Parma, Italy)

Video-induced yawning in stumptail macaques (Macaca arctoides), by Annika Paukner* and James R Anderson, Biol Lett v.2(1); Mar 22, 2006

Monkeys can "catch" yawns from each other, too, Guardian, December 7, 2005

A yawning ape is a perceptive ape, New Scientist, 31 July 2004

Imitation as faithful copying of a novel technique in marmoset monkeys, PLoS one

(Answered June 9, 2008)

Readers' Answers

· Nope. If you yawn in front of a monkey, it's gonna do one of two things: screech at you or poke its finger in your mouth.
Bridgit Stone-Budd Sanibel, Captiva Islands, Florida

· In humans, contagious yawning has been connected to empathetic people. Empathetic people tend to yawn, when they see others yawn, compared to people that are not that empathetic. My guess is that the same holds true for monkeys. Some will yawn and some won't, depending on their empathy quotient.
Sukumar, Chennai, India

· If a Monkey copies everything you do, I imagine it can yawn.
Babar Ahmed, 12 years old, Philadelphia, Pennsylvania

· Monkeys imitate. But it is not proven that yawning is contagious. Therefore, monkeys, after seeing someone yawn, would probably open their mouth but are they are actually yawning? Probably not, their brains don't work exactly like humans.
Dan Peacock, Port Hope Ontario, Canada

· It depends how bored the monkey is at the time...
Eyar Ouziel, Tel-Aviv, Israel

· I believe a MONKEY WILL yawn; I am going on the "monkey see, monkey do" theory. Thanks for the fun!
Barb Del Piano, Somewhere, World