Phyllis Jay briefly touches on the subject of primates swimming in the book Behavior of Nonhuman Primates; in discussing the habitat of African monkeys, Jay writes (Jay, 1965, p. 535) that the "…distribution of arboreal monkeys is restricted by open, relatively treeless areas" and "rivers are barriers to arboreal monkeys but not to terrestrial forms, many of which swim" (Jay, p. 535).

"Long-tailed macaques are excellent swimmers, and this may be a predator avoidance technique," writes the University of Wisconsin's Kristina Cawthon Lang in Primate Factsheet. If the long-tailed macaque is threatened by a feral dog, raptor, python, monitor lizard or large cat, the macaque simply drops into the water and swims to safety (Lang, 2006).

In its "Science & Nature: Animals" section, the British Broadcasting Company (BBC) published a story on the Long-tailed Macaque: "Long-tailed macaques swim well and jump into the water from nearby trees" (BBC).

In his book, Primate Anatomy: An Introduction, Friderun Ankel-Simons explains that Macaques (not "Long-tailed macaques") live in many areas of the world, including Asia (India north to Afghanistan, Nepal, Burma, and Tibet, Thailand, Southern China, all the way east to Japan), the Philippines, Sri Lanka, Borneo, and sometimes the Macaques are established in artificial colonies.

One of those colonies is off the coast of Costa Rica, on an island called Santiago Island, that has been "under constant scientific observation" since the colony was established in 1938. While Macaques thrive in many environments (because they are so adaptable), including snow and tropical rainforests, the Macaques on Santiago Island "go swimming in the surf" (Ankel-Simons, p. 104). One wonders if the Macaques observed human surfers plying their talents in the surf, and decided to go out and imitate what the humans did. Or, if they just, out of curiosity -- because of the constant thundering surf that got their attention day and night -- they one day went out and began trying to emulate...

According to the Times, a chimpanzee had escaped from a traveling zoo in Rockaway, New Jersey. "It slipped away from its cage and swam the Rockaway River" (Times, 1926). Apparently no one actually saw the chimpanzee swimming across the river, but when they caught up with the chimp it was on the other side, vaulting from one tree to the next. The zoo's proprietor, Francis Murphy, found the animal in the woods on the other side of the Rockaway River and when the chimp saw Murphy, who had called to it, "it walked into the arms of its captor" (Times, 1926).
Works Cited

Ankel-Simons, Friderun. (2007). Primate Anatomy: An Introduction. St. Louis:

Academic Press.

British Broadcasting Company. (2007). Long-tailed macaque, crab-eating monkey, Java

Monkey, cynomolgus monkey. Retrieved June 5, 2009, from http://www.bbc.co.uk/nature/wildfacts/factfiles/210.shtml.

Britton, Dave, Groves, Colin, and Boles, Walter E. Aquatic Apes? Nature Australia,

28(2), 82-83.

Coleman, Loren. (2007). Mysterious America: The Ultimate Guide to the Nation's

Weirdest Wonders, Strangest Spots, and Creepiest Creatures. New York: Simon

And Schuster.

Hopkins, Bob. (2008). Sussex County YMCA. Retrieved June 5, 2009, from http://www.seim-inc.org.

Lang, Kristina Cawthon. (2006). Primate Factsheets: Long-Tailed macaque (Macaca

Fascicularis) Taxonomy, Morphology, & Ecology. Retrieved June 4, 2009, from http://pin.primate.wisc.edu/factsheets/entry/long-tailed_macaque.

Smith, Lewis. (2008). Swimming orang-utans' spearfishing exploits amaze the wildlife

Experts. London Times / TimesOnline. Retrieved June 4, 2009, from http://www.timesonline.co.uk.

The New York Times. (1926). Chimpanzee Chase is Latest in Jersey. Retrieved June 5,

2009, from ProQuest Historical Newspapers.