sciencehabit writes: Researchers have the first video evidence that apes can learn to swim and dive. A chimpanzee named Cooper and an orangutan named Suryia, both raised in captivity and regularly exposed to bathtubs and swimming pools, developed unexpected underwater skill. Reassured by the presence of a safety rope, Cooper became increasingly adventurous over a period of days: He could tread water, submerge himself (with eyes shut tight), and propel himself with a kick reminiscent of the human breaststroke. Suryia also opted for a breaststroke-esque kick, but took his skills a step further, opening his eyes underwater and traveling up to 4 meters while submerged for as long as 15 seconds. The researchers offer an evolutionary explanation: When an early ancestor of modern apes took to the trees, they say, innate swimming ability likely lost its advantage, and the trait disappeared. The fact that our muscles and brains adapted to graceful swinging movements in the air and upright walking on the ground might account for the lengthwise reaching and pulling movements that define Cooper and Suryia’s aquatic style.