Some facts about otters

   Few people have seen more of an otter than the streak of bubbles that follows behind it as it swims at speed underwater. Otters are shy, cautious animals and usually come out only at night, especially in areas where they are hunted or likely to be disturbed.

   They live in lakes, rivers, streams — wherever the water is clean and they are left in peace. They are also often found along rocky western coasts, for what is known as the ‘sea otter’ of Europe is not in fact a different animal at all.

   They shelter by day in holes in the river bank, in old drains, or amongst the roots of riverside trees. The breeding den or 'holt' is in a similar place and is usually lined with reeds and grass. Here the cubs are born and spend their first two months.

   Otters can be very playful, making slides down banks of mud or snow, and stopping to investigate any strange objects they find. Cubs especially will twist and turn with great speed in the water as they play 'tag', and will sometimes dive to the bottom of the river for pebbles which they play with like toys.

   The otter is beautifully designed as an underwater hunter. Shaped like a torpedo, it can reach speeds of 10 kilometres an hour underwater. It swims by waving its body, like a snake moving on land. The webbed feet help when it needs a burst of speed, and the flattened tail is used as a rudder for steering.

   When the otter dives its nostrils close, but it can hold its breath underwater for up to four minutes and travel up to 400 metres. On land its senses of smell and hearing are very good. But when it dives with its ears and nostrils closed, it must rely on its eyesight. Its whiskers may also help it to sense the movement of its prey, and to find its way in cloudy water.

   Approaching with speed, an otter catches fish from underneath, often using its front paws. There is no doubt that it does kill trout and salmon from time to time. This upsets fishermen and gamekeepers, some of whom still set traps for the otter. However, scientists have shown that its main food is fish such as perch and pike, which are no use to fishermen. Where eels are common, the otter will kill large numbers of these. As eels feed on salmon and trout eggs, the otter may well be helping the fishermen by killing eels.