Regarding moles, the Star-nosed Mole (so named from the pink tentacles that surround its snout) is highly aquatic and an expert swimmer and diver. But even the common garden mole can swim fairly well (ref: Walker’s Mammals of the World).
Given this, the observation of the drowning gopher is somewhat surprising, since one would not necessarily expect them to have less swimming capacity than moles, based on anatomy. The references I have consulted so far are mysteriously silent on the subject. Perhaps the animal in question saw the end was near in any case and decided to drown itself in despair. Clearly more experimentation is needed. For what it’s worth, gophers tend to be found in drier areas than moles, and so perhaps encounter water less often. (Maybe I need to try looking this up under “Varmint Control” rather than “Mammalogy.”)
Excellent post by APB, which nicely summarizes the anatomical constraints. However, one factor missing is the psychological side of the question. An animal could be perfectly capable of swimming with respect to its anatomy, but drown if it reacted adversely to finding itself in the water. This was part of my speculation that many smaller land birds might not be able to swim (even though they float very well, and are capable of moving their limbs in the water). Interesting post on the swimming eagle, BTW.
Psychological factors may in fact have something to do with the apparent inability of the Great Apes to swim, even though they are anatomically so similar to humans. In “The Apes,” (Vernon Reynolds, 1967, pp. 87-88) we find the following rather definite statements:
“Swimming ability is almost nil in the apes. A young gibbon that fell into a pond at a zoo drowned while its mother watched, too afraid to rescue it. No report of swimming by a gibbon exists, but several others confirm its inability to swim. Orangutans have never been observed swimming, and probably cannot. Gorillas, faced with the alternative of capture by man, dare not go into water more than two or three feet deep. They have never been observed to swim, and at least one mature male has drowned in a zoo water enclosure, sinking as soon as he fell in. Only in chimpanzees is there some evidence for swimming ability. [Reynolds then cites a report of four chimpanzees seen swimming across a river in Africa, but then says he is inclined to think it must really have been some other species.] In captivity, attempts to teach chimpanzees to swim have met with failure, and deepwater barriers have often proved efficient in keeping apes on islands, as for example at the Paris Zoo. The general response of chimpanzees to water is universally agreed to be one of avoidance and even fear. I have myself on two occcasions helped pull chimpanzees out of a water-filled moat in which they were quite clearly drowning, and I am convinced they cannot swim, although in their stuggles as they flounder about they can sometimes make a little headway in the water.”
I think the jury is still out on giraffes, though APB’s points incline me to reverse my earlier opinion that they could’t. Awkward they certainly might be, but I don’t see a definite anatomical reason why they wouldn’t be able to swim, particularly with the neck stretched out horizontally to the water.