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.