PS. As a follow-up to my previous post, the case of the “drowning gorilla” mentioned in many references seems to be based on an incident at the Bronx Zoo in the late '40s or early 50’s, when a full-grown adult male gorilla tumbled into the moat of his enclosure and drowned with scarcely a struggle in full view of a crowd of horrified and astonished spectators. When I find out the name of the gorilla, I’ll let you know.
Earlier in this thread someone speculated that kangaroos might not be able to swim. No luck. They do. Peculiarly enough, they use the hind feet alternately while swimming, something they appear to be quite unable to do on land (always hopping, never walking).