Because I teach biological anthropology, I'm reading a lot of student work this week that focuses on the African apes, chimpanzees, bonobos and gorillas. During this end-of-semester grading marathon, I've got a festive balance going: grade a handful of papers; grab a Christmas cookie; grade a handful more; wrap a present or two.

More than once, I've taken a break to view a brief video that one of the students in my primate behavior class sent me. The student — in preparing her research paper on chimpanzees' ability to deceive others intentionally — discovered this minute-long clip filmed among chimpanzees in the West African nation of Guinea (see here for more information):

Jane Goodall's decades of work among wild chimpanzees in Tanzania has taught us that chimpanzee mothers are loving and patient, carrying their youngest infants round-the-clock and continuing to care for them intensely for years. But the Guinea video gives us a glimpse of the sneaky side of maternal behavior!

Deception is by no means limited to African apes: I'd guess that many 13.7 readers who live with dogs would report that their canine companions deliberately try to deceive them now and again — in order to avoid punishment for some misdeed or to gain extra treats. But chimpanzees aren't domesticated animals, as dogs are. The clip shows ape-to-ape deception carried out with special flair.

And the mom's facial expression when she grabs her son's tools is priceless.

The Guinea chimpanzees go beyond the termite-fishing and ant-dipping technology of Tanzanian chimpanzees: These apes are cracking open hard nuts using a hammer-and-anvil system. Not only is this whip-smart behavior that takes years to learn, it's also an example that points to chimpanzee culture, population-by-population variation based not in ecological differences across habitats but instead in the customs passed down from one generation to the next.

As our closest living relatives (along with bonobos), chimpanzees fascinate me for who they are and also for their central significance in helping us think about how we, ourselves, evolved over millions of years. I could write much more about them today — but that stack of still-ungraded papers is giving me the eye.

Barbara'smost recent book on animalswas released in paperback in April. You can keep up with what she is thinking on Twitter:@bjkingape.

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