Clever Orangutans Confirm Aesop’s Fable
Orangutans, using water and their wits, have emulated a crow in Aesop’s fable which illustrated the saying “Necessity is the mother of invention,” German researchers report.
A team at the Max Planck Institute for Evolutionary Anthropology in Leipzig threw down a challenge to five female orangutans, aged seven, 11, 16, 17 and 32, housed in the local zoo.
The apes were presented with a tasty peanut that floated in a plastic tube. The container was a quarter-filled with water, which meant that the nut was frustratingly out of reach to the animals.
The orangutans realized, though, that by taking mouthfuls of water from a cup placed nearby and spitting the water into the tube, they could make the nut float to the top and recover it easily.
At the start, it took the apes nine minutes on average to figure out the trick. But by the end of the 10-trial experiment, they had whittled this down to a zippy 30 seconds.
The Leipzig team believe this illustrates orangutan inventiveness, showing the primates can use a “liquid tool” to get a reward. Breaking the tube was impossible and there was no stick available as an alternative retrieval method.
The study appears in Biology Letters, published by Britain’s Royal Society, the de-facto British academy of sciences.
In Aesop’s fable, a thirsty crow finds a pitcher of water but the water level is so low as to be out of reach. The bird places stones in the pitcher to raise the water level and thus quench its thirst.Filed under: Headlines