Two researchers have provided the first video-based observation of swimming and diving apes. Instead of the usual dog-paddle stroke used by most terrestrial mammals, these animals use a kind of breaststroke. The swimming strokes peculiar to humans and apes might be the result of an earlier adaptation to an arboreal life.
For many years, zoos have used water moats to confine chimpanzees, gorillas or orangutans. When apes ventured into deep water, they often drowned. Some argued that this indicated a definitive difference between humans and apes: people enjoy the water and are able to learn to swim, while apes prefer to stay on dry land.
But it turns out that this distinction is not absolute. Renato Bender, who is working on a PhD in human evolution at the School of Anatomical Sciences at Wits University, and Nicole Bender, who works as an evolutionary physician and epidemiologist at the Institute of Social and Preventive Medicine at the University of Bern, have studied a chimpanzee and an orangutan in the US. These primates were raised and cared for by humans and have learned to swim and to dive.
'We were extremely surprised when the chimp Cooper dived repeatedly into a swimming pool in Missouri and seemed to feel very comfortable,' said Renato Bender.
To prevent the chimp from drowning, the researchers stretched two ropes over the deepest part of the pool. Cooper became immediately interested in the ropes and, after a few minutes, he started diving into the two-meter-deep water to pick up objects on the bottom of the pool. 'It was very surprising behavior for an animal that is thought to be very afraid of water,' said Renato Bender. Some weeks later, Cooper began to swim on the surface of the water.
The orangutan Suryia, who was filmed in a private zoo in South Carolina, also possesses this rare swimming and diving ability. Suryia can swim freely up to twelve meters.
Both animals use a leg movement similar to the human breaststroke 'frog kick'. While Cooper moves the hind legs synchronous, Suryia moves them alternatively. The researchers believe that this swimming style might be due to an ancient adaptation to an arboreal life. Most mammals use the so-called dog-paddle, a mode of locomotion that they employ instinctively. Humans and apes, on the other hand, must learn to swim. The tree-dwelling ancestors of apes had less opportunity to move on the ground. They thus developed alternative strategies to cross small rivers, wading in an upright position or using natural bridges. They lost the instinct to swim. Humans, who are closely related to the apes, also do not swim instinctively. But unlike apes, humans are attracted to water and can learn to swim and to dive.
'The behavior of the great apes in water has been largely neglected in anthropology. That's one of the reasons why swimming in apes was never before scientifically described, although these animals have otherwise been studied very thoroughly. We did find other well-documented cases of swimming and diving apes, but Cooper and Suryia are the only ones we were able to film. We still do not know when the ancestors of humans began to swim and dive regularly,' said Nicole Bender.
'This issue is becoming more and more the focus of research. There is still much to explore,' said Renato Bender.
The first was a young chimpanzee named Cooper, who not only figured out how to swim but could also dive underwater to retrieve items from the bottom of a swimming pool. The second ape was Suryia, an orangutan living in a zoo in South Carolina. Suryia was recorded swimming about 39 feet (12 meters) without assistance.Can apes swim and dive? ›
These primates – Cooper the chimp and Suryia the orangutan – were raised and cared for by humans and have learned to swim and to dive.When did humans first learn to swim? ›
Swimming has been recorded since prehistoric times, and the earliest records of swimming date back to Stone Age paintings from around 7,000 years ago. Written references date from 2000 BC.Do apes know how do you swim? ›
Researchers now have the first video evidence that apes can learn to swim and dive. Like humans, wild apes exposed to deep water will fumble and flail. Our uncoordinated movements bear little resemblance to the tried-and-true doggy paddle that most other mammals use instinctively.Can any of the great apes swim? ›
Most mammals are able to swim instinctively without training; a notable exception being the great apes. Humans are clearly able to become proficient swimmers with training; other great apes, however, have not been documented as swimmers beyond anecdotal reports.What is the underwater ape theory? ›
The Aquatic Ape Theory states that our ancestors once spent a significant part of their life in water. Presumably, early apes were plant and fruit eaters in tropical forests. Early hominids also ate aquatic food; at first mainly weeds and tubers, later sea shore animals, especially shellfish.Can primates naturally swim? ›
Apart from baboons wading in intertidal rockpools for food and capuchins foraging in mangroves at low tide, very few primates other than humans actually swim well or regularly.