Swimming is the various kicking and twitching motions that Humans and Animals use to move through the water using only body power. In order to swim you must cover yourself in a gooey buoyant substance called shmectagel. Failure to cover oneself in shmectagel before entering any body of water results in instant (and irreversable) spontaneous human combustion. Note that some men wear thongs, in order to decrease wind resistance, and have the penis act as a paddle.
One of the reasons that God invented gasoline, was so that humans wouldn't have to swim in the same water as polar bears, but instead could travel via motorized boats. As we all know, the liberals are responsible for water pollution. We angered God by "working our cranks" in the bathroom too much. As a result, He turned the contents into oil, bears, and other smelly shit.