Cracking nuts is something we humans take for granted, but for hammer-wielding orangutans (a small selection, anyway) this skill is a new string to their bow in the eyes of primatologists. The use of a hammer – or hammer-like object – to break nuts had previously been recognized in other primate species, but now new research has found that some captive orangutans are capable of intuitively working out how to turn their hand to nut smashing without the need to be taught.
The new open access paper, published in the American Journal of Primatology, set to find out if these great apes could utilize tools provided to them when faced with a nut that needed to be cracked. They argue that nut-cracking is likely something these animals don’t practice in the wild owing to the fact that an arboreal lifestyle doesn’t lend itself very well to such a way of foraging. After all, it’s all well and good having broken the shell but not much use when the precious contents have pinged off into the abyss.
They put four orangutans at Leipzig Zoo, Germany, to the test to find out. Each animal was provided with some nuts and hammers but there was no demonstration by the keepers as to how the two could interact. One of the four in their experiment was able to start cracking nuts without tuition, demonstrating that it can emerge in these animals even when they’ve not learned the behavior from other animals.
The researchers also report data from a previously unpublished study led by co-author on the new paper Martina Funk, who tested eight orangutans at Zürich Zoo using similar conditions. Here, three orangutans demonstrated an affinity for nut-cracking, meaning that out of the total twelve animals tested, at least four individuals (one-third) were able to utilize the hammers to crack nuts.
The findings aren’t the first time orangutans have been shown to be proficient in tool use. Memorable footage saw one orangutan quite happily wielding a handsaw, while a captive orangutan in Dublin Zoo, Ireland, recently found a novel use for the teddy bear of one crestfallen child (TW: contains scenes of ruthless teddy tearing).
“Nut-cracking with hammer tools ... has been argued to be one of the most complex tool-use behaviors observed in nonhuman animals,” write the study authors. “So far, only chimpanzees, capuchins, and macaques have been observed using tools to crack nuts in the wild.”
“These results demonstrate that nut-cracking can emerge in orangutans through individual learning and certain types of non-copying social learning.”
