The Bigfoot Evidence blog recently posted an entry entitled “Yes, Bigfoot Can Swim: Scientists Prove That Apes Can Swim and Dive.” The entry highlights a recent Science Daily article about a chimpanzee and an orangutan with the ability to swim and dive underwater, the first such behavior described for apes. I’m amazed that this is being offered up as evidence that Bigfoot can swim. This is wrong for at least three reasons. First, there is no way to verify reports of swimming Bigfoots. Other than unreliable eyewitness accounts–often passed on in the form of hearsay by those who did not see the creature–there is no video or photographic evidence of any kind to support the stories. Some people may believe they are telling the truth, but errors, such as misidentifying a known animal (e.g. bears), cannot be ruled out (nor can hoaxing).  The folklorist Kathrine Briggs makes a distinction between fairy tales, which are believed to be fictional, and folk tales, which are believed to be true.  And since the latter contains uncorroborated elements, reports of swimming Bigfoots are no more credible than legends of giants, fairies, ghosts, and witches that were once commonly circulated–essentially making them modern folklore. They would never be accepted as evidence in a court of law, nor could they pass for scientific evidence.
Second, the swimming of the aforementioned apes is human-induced behavior. The original study, “Brief communication: Swimming and diving behavior in apes (Pan troglodytes and Pongo pygmaeus): First documented report,” mentions how the chimp Cooper and the orangutan Suryia were both raised by humans in a home and in a private zoo, respectively. Both were exposed to water from a young age: first through baths and later during supervised playtime in the shallow end of pools. Although this study invalidates the long held idea that apes can’t swim due to their dense anatomy, there is clearly an environmental factor at play that keeps these creatures from swimming in the wild (see below). Cooper and Suryia would not have developed these skills without the encouragement of their human parents/keepers. Therefore, it should be stressed that their abilities are unique among apes the world over. This means the study is nothing more than a scientific anecdote. As the primatologist William C. McGrew points out: “All that an anecdote can do is alert us to a possibility, so that we will look for it again.”  In addition, he warns that “citing specific events as evidence for something broader [can lead] to overgeneralization.”  This leads me to my last point.
A video of Suryia the Orangutan swimming.
Third and most importantly, wild and captive apes typically shun large bodies of water. The aforementioned study mentions that the scientific literature “indicate[s] that apes’ behavior towards water bodies in the wild might be adaptive—they avoid deep water bodies and are extremely cautious when entering even shallow water.” The authors suggest this hydrophobia is a survival strategy since apes probably lost the instinctual swimming ability that most terrestrial mammals have because they spend most of their lives in or near trees. This explains why apes have never been observed drowning in the wild. Captive apes, on the other hand, often drown in the moats that zoos use to keep them confined to their outdoor habitats. This is because they have more exposure to bodies of water than they do in the wild. Dr. Roger Fouts somberly describes a captive drowning in his wonderful book Next of Kin: My Conversation With Chimpanzees (1997):
One morning I couldn’t find Candy and I became worried that she had attempted to jump the moat and had drowned. My students and I waded into the water up to our chests and began dredging the muddy bottom with poles. After an hour or so, I felt her small body under my feet, and went down to retrieve it. As I emerged from the moat, cradling Candy’s lifeless body in my arms, the other chimps kept their distance…I had never seen, much less held, a dead chimpanzee before. It was heartbreaking. Chimpanzees, like human children, are so animated in every expression, so vibrant in every leap, that their spirit seems like the very essence of life itself. Drained of Candy’s spirit, the stiff body I held was just an empty vessel. 
So, in the end, this attempt to support modern folklore with an unrelated scientific anecdote further relegates Bigfootology to the realm of pseudoscience. Proponents of cryptozoology are often accused of not being objective enough,  and this serves as a prime example of this. They focus on all the evidence that they feel supports their views–even going so far as to twist data to fit like above–while ignoring all that invalidates them.
 See the section on “Misidentification Errors” in Daniel Loxton and Donald R. Prothero, Abominable Science!: Origins of the Yeti, Nessie, and Other Famous Cryptids (New York: Columbia University Press, 2013), 56-59. A 2009 study found Bigfoot and Black Bears (Ursus americanus) (un)coincidentally share the same territory. See ibid, 57.
 Katharine M. Briggs, A Dictionary of British Folk-Tales in the English Language: Part B : Folk Legends : Vol. 1 (London: Routledge & Kegan, 1971), vii-viii.
 William Clement McGrew, The Cultured Chimpanzee: Reflections on Cultural Primatology (Cambridge [u.a.]: Cambridge University Press, 2004), 79.
 Ibid, 175-176.
 Roger Fouts, Next of Kin: My Conversations With Chimpanzees (New York: Bard Books Inc, 1997), 179.
 See for example Loxton and Prothero, 65-66.
Briggs, Katharine M. A Dictionary of British Folk-Tales in the English Language: Part B : Folk Legends : Vol. 1. London: Routledge & Kegan, 1971.
Fouts, Roger. Next of Kin: My Conversations With Chimpanzees. New York: Bard Books Inc, 1997.
Loxton, Daniel, and Donald R. Prothero. Abominable Science!: Origins of the Yeti, Nessie, and Other Famous Cryptids. New York: Columbia University Press, 2013.
McGrew, William Clement. The Cultured Chimpanzee: Reflections on Cultural Primatology. Cambridge [u.a.]: Cambridge University Press, 2004.