At the beginning of this clip the otters appear to rooting around the pond bottom to get fish just as they have in most of the other previous clips. Then they begin a more methodical, almost measured swimming as they look for fish. You can almost feel them focus on the pond water below them. At the end of this clip one otter performs a technique called porpoising, that rapid, undulating up and in motion through the water that porpoises, dolphins and other marine mammals and penguins perform to perfection. The laws of physics suggest that this is a way to conserve energy, since they get less resistance from air than from water, but merely conserving energy doesn't seem to be a problem for young otters in a pond. They are not out in the ocean like other porpoising animals. I always think it's too easy to explain away types of otter behavior by saying that they're playing. These otters are after fish. Staying under water for several minutes and chasing fish, while possible, must be stressful because otters do have to remember to come up for air. So working themselves into a rhythm in which they can breath air frequently yet at the same time keep up their speed and extend their sensing of the water below must be an optimum way to go after fish.

Swimming in the deeper pond seemed to unleash the extra energy a pup has. How lucky I was to get this on video, a brief glimpse at some real porpoising:

Turn the page and take a look: page21

Here is a rough guide to the video clips in the video book.