Otters are aquatic or
marine carnivorous mammals, members of the large and diverse family
Mustelidae, which also includes weasels, polecats, badgers and
others. There are 13 species of otter in 7 genera, with a distribution
that is almost worldwide.Physical characteristics Otters have
a dense layer 1,000 hairs/mm² (~650,000 hairs/in²) of
very soft underfur which, protected by their outer layer of long
guard hairs, keeps them dry under water and traps a layer of air
to keep them warm. Unlike most marine mammals (seals, for example,
or whales), otters do not have a layer of insulating blubber,
and even the marine sea otter must come ashore regularly to wash
its coat in fresh water. All otters have long, slim, streamlined
bodies of extraordinary grace and flexibility, and short limbs;
in most cases the paws are webbed. Most have sharp claws to grasp
prey but the short-clawed otter of southern Asia has just vestigal
claws, and two closely related species of African otter have no
claws at all: these species live in the often muddy rivers of
Africa and Asia and locate their prey by touch.
|
|
Fish is the primary
item in the diet of most otters, supplemented by frogs, crayfish,
and crabs; some have become expert at opening shellfish, and others
will take any small mammals or birds that happen to be available.
To survive in the cold waters where many otters live, the specialised
fur is not enough: otters have very high metabolic rates and burn
up energy at a profligate pace: Eurasian otters, for example,
must eat 15% of their body weight a day; sea otters, 20 to 25%,
depending on the temperature.
Images 1 Though 6 Are From The U.S. Fish & Wildlife Service
Images 7 Through 18 Are From The National Parks Service
|
