Chimps Recognize Butts the Way Humans Recognize Faces

iStock
iStock

Recognizing a fellow human’s face is about more than just identifying a nose or mouth. It’s believed we use something called configural recognition to process the entire facial structure altogether, which is why there’s often a little bit of a lag time when we see a face upside-down (humans have an easier time recognizing other objects, like cars or houses, that have been flipped).

Researchers now believe chimpanzees have something similar to configural recognition. Only they use it to recognize each other’s butts.

In a paper published in the journal PLOS One, researchers from the Netherlands and Japan observed chimps as they examined photographs of primate buttocks and played a variation on the “match” game, coupling two identical butts together on a touch screen. They appeared slower to recognize posteriors when the images were rotated 180 degrees, indicating they rely on the same configural clues humans do. The researchers also carried out experiments on humans, who (as expected) took a longer time to process images of human faces flipped upside-down, but whose reaction time didn't change significantly when they were presented with upside-down images of human behinds.

It’s believed chimps have evolved to focus on butts due to their proximity to them while moving in groups. Walking on four legs, they’re often (literally) faced with a rump ahead of them. Since ovulating females usually have red, swollen rear ends, male chimps benefit from being able to identify them. What’s more, chimps can typically separate an ovulating non-relative from a relative, preventing inbreeding.

The paper concludes, "The findings suggest an evolutionary shift in socio-sexual signalling function from behinds to faces, two hairless, symmetrical and attractive body parts, which might have attuned the human brain to process faces, and the human face to become more behind-like."

[h/t Discover]

Take Advantage of Amazon's Early Black Friday Deals on Tech, Kitchen Appliances, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

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Pretty in Pink: Drone Captures Birds-Eye View of Massive Flamingo Flock in Kazakhstan

MORAN, Unsplash
MORAN, Unsplash

Flamingos sport some of the most eye-catching plumage in the animal kingdom. Their diet of beta-carotene-rich plankton and crustaceans produces a distinctive pink hue that's hard to miss. One flamingo is striking on its own, but the birds are even more impressive as a crowd, as demonstrated by the footage below.

As Fox 13 Tampa Bay reports, Azamat Sarsenbayev used a drone to capture this video of flamingos congregating on Lake Karakol near Aktau, Kazakhstan. A flamingo flock (also called a flamboyance) can contain up to several hundred birds. Flamingos do a lot together, including mating displays. From above, everyday life for a flamingo makes for a breathtaking, candy-colored spectacle.

This footage was taken during the species' migration south. By the end of their journey, the birds will likely be settled in the Khazar nature reserve or even farther south in Iran. After checking out the video, read up on these fascinating facts about flamingos.

[h/t Fox 13]