The tarsiers of the Philippines are the smallest primates on the planet, at about five inches tall. They tend to keep their hind legs, which are twice as long as their bodies, folded up frog-style, except when leaping on their insect prey. And a tarsier eyeball, at just over half an inch wide, is as large as a tarsier brain.
But the weirdness doesn’t stop there. No, it most certainly does not.
Scientists had previously remarked that tarsiers were unusually quiet. And they also seemed to yawn quite a lot. Aww, cute, right? Sweepy wittle pwimates! But then, some scientists studying tarsiers made a startling discovery. Zoe Corbyn at New Scientist sums it up well: “Placing 35 wild animals in front of an ultrasound detector revealed that what [the scientists] assumed to be yawns were high-pitched screams beyond the range of human hearing.”