Otters are so proficient at capturing the fish they live on, that they have lots of time left over for play. And they seem to play with reckless abandon, sliding down steep canyons in deep snow, swimming under the ice in Yellowstone Lake. They submerge us into the lake to find strange underwater spires only recently discovered by man. Other creatures sometimes survive bitter winter seasons by stealing fish from the otter. Actually, they're pretty good at defending themselves, and this program catches some astonishing action between them, coyotes, eagles, beaver, even an occasional grizzly bear.

• Trailwood Films