For the first time, wild mountain gorillas have been seen playing in water and having a splashing good time.
Raquel Costa of Kyoto University in Japan spotted the behaviour by chance. She studies the impact of ecotourism on the wild mountain gorillas (Gorilla beringei beringei) living in Bwindi Impenetrable National Park in Uganda.
In January 2018, Costa saw a 15-year-old male gorilla named Kanywani sitting by a stream. He was gently moving his arm backwards and forwards in the water. However, he only did it for 37 seconds in total and she did not have a camera.
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The next time, Costa was able to record the behaviour. It was two weeks later and most of the group was feeding by the stream. A nine-year-old female named Kamara started splashing the water with her arms, vigorously sweeping it to the sides. She did this 21 times in 17 minutes, always making a distinctive 鈥減lay face鈥� in which she stuck out her tongue. At one point a second female, Kanyindo, briefly joined in. By the end, 鈥淜amara was completely wet鈥�, says Costa.
About a week later, Costa again briefly saw a gorilla play in the stream. This time it was seven-year-old male Kabunga, who rotated his arms across the water surface for about five seconds.
Making a splash
found no evidence of water play in mountain gorillas, either from Bwindi or from the other population in Virunga National Park in the Democratic Republic of the Congo. However, Costa says colleagues studying the Virunga gorillas told her they have seen water play.
Elsewhere, western lowland gorillas are known to dramatically splash in water, seemingly as a display of power. Famously, in 2017 Dallas Zoo released a video of an adult male western lowland gorilla, Zola, . The clip promptly went viral.
Most studies of animals playing focus on social play, in which two or more animals play a game together. However, Costa says solitary play can be equally important. While social play helps animals learn social skills, solitary play can be a way to learn physical skills and to explore their environments. By playing in water, the gorillas are 鈥渄eveloping muscles and skills鈥�, she says.
Besides learning, water play may offer 鈥渢he pure pleasure of doing something鈥�, says Costa. Just like human children love water play, gorillas may also do it for fun. 鈥淚 do feel that animals with a certain cognitive capacity will do something just because they enjoy it.鈥�
Primates
