Can gorillas swim

Great apes first filmed swimming

For the first time, researchers observed and filmed great apes swimming. The recordings show that the monkeys do not move their arms and legs like most other mammals, but rather like humans when swimming breaststrokes. In addition, they too have to learn to swim first - just like us humans. This could indicate that the ancestors of great apes and humans behaved differently in water than other mammals, according to the researchers in the American Journal of Physical Anthropology.

Up until now, chimpanzees, gorillas and orangutans were thought to be afraid of water and incapable of learning to swim. This is one of the reasons why many monkey enclosures in zoos and animal parks are still surrounded by moats. In fact, monkeys often drown when they get into deep water. For a long time, it was assumed that this is one of the many differences between humans and great apes: we like water and learn to swim, the monkeys avoid it.

Diving chimpanzee and swimming orangutan

But two human-raised monkeys, a chimpanzee and an orangutan have now taught primatologists at the University of Witwatersrand in South Africa and the University of Bern wrong: “We were extremely surprised when the chimpanzee Cooper dived several times in a swimming pool and found himself Apparently felt very comfortable ", reports Renato Bender from Witwatersrand University. The researchers stretched two ropes through the pool to prevent the chimpanzee Cooper from getting into the deep water. Instead, the animal dived for objects that were at the bottom of the two-meter-deep basin. "That was amazing behavior for an animal that is supposedly afraid of the water," says Bender.

Orangutan Surija filmed swimming © Wiley / American Journal of Physical Anthropology

A little later, the scientists also observed Cooper swimming around on the surface of the pool. The orangutan Suriya, who grew up in a private zoo in South Carolina, showed similar behavior: it can swim up to twelve meters and does so quite often. The striking thing about both swimming great apes: Neither of the two animals showed what is known as dog paddling, which other mammals instinctively use to move forward. Instead, the chimpanzee moved its hind legs mostly synchronously, the orangutan his alternately. But both of them scooped the water to the side with their arms - not down like when paddling a dog.

Humans and monkeys have forgotten how to paddle instinctively

In the meantime, the researchers have also learned about other great apes that can swim as well as dive. “But Cooper and Suriya are the only ones we were able to film,” says Nicole Bender from the University of Bern. The behavior of great apes in water has so far been largely neglected by anthropology. “That is one of the reasons why the swimming of great apes has never been scientifically described before,” says Renato Bender.

In the opinion of both researchers, the swimming movement of the great apes indicates something in common between them and humans: the ancestors of both may have lost the instinctive ability to swim using dog paddles in the course of development. Instead, they used their ability to stand up, for example to wade across shallow rivers. If the water is too deep to wade, the great apes obviously do not begin to swim instinctively, but have to learn the technique to do so first - just like us humans.

“We don't yet know when man's ancestors began to swim and dive more often,” says Nicole Bender. At this point, much is still unclear and needs to be researched first. (American Journal of Physical Anthropology, 2013; doi: 10.1002 / ajpa.22338)

(Wits University, 08/15/2013 - NPO)

15th August 2013