[CHAPTER I]
THE NATURAL HISTORY OF THE OTTER
The common otter of the British Islands, known in scientific classification as Lutra vulgaris, belongs to the Mustelidæ, or in other words the weasel family. Included in the latter are the martens and their allies, whose chief attributes are activity, length of body and tail, shortness of legs, widely separated toes, and small claws. The otter is the possessor of similar attributes, with additional developments to fit it for an aquatic existence. If therefore we describe the otter as an aquatic marten, living chiefly on a fish diet, we shall probably not be deviating very far from the truth. Swimming is an inherited instinct handed down through the ages, and though it has been lost by man, it has been developed and taken advantage of by many creatures, in order to enable them to lead an aquatic existence. The reason for this intensive development of their swimming powers by certain animals probably lies in the fact that aquatic life opened a wider and safer field for them, both in the matter of food supplies and protection from their natural enemies.
The otter family is widely distributed over the globe, so before entering upon a detailed description of our British otter, it may be of interest to glance at other species inhabiting foreign countries. The typical otters are marine as well as aquatic in their habits, many of them visiting the sea, where they live in the caves and other retreats along the coast. There is one of the family, however, i.e., the sea-otter, which is entirely marine. The skin of this otter has always been keenly sought for by fur-traders and trappers, and it is owing to constant harassing by such people that the sea-otter is now all but extinct. This otter differs in many ways from its aquatic relations. It possesses large flipper-like hind feet, a short tail, and small, delicate forefeet. The hind paws alone are used for swimming, the delicate and sensitive forefeet being employed in locating the otter's food, consisting of mussels, crabs, and other shell-fish, which it hunts for amongst the rocks at the bottom of the sea. This otter spends its entire existence in salt water, and has been found as far as twenty miles from land.
The female usually has but a single young one, born, so it is thought, on the large beds of seaweed commonly known as kelp. Lying on her back in the sea, the mother sleeps and suckles her baby in that position.
In Africa there is a species known as the spotted-necked otter, which has shorter ears, longer toes, and more hair about its nose than the common otter. Africa also produces a large otter which has more or less given up its aquatic habits. The claws on this otter's forepaws have disappeared, while those on the hind feet have practically done so. In India there is a small otter whose claws resemble those of the foregoing, and in both animals the sense of touch in the forepaws is extremely delicate, which no doubt enables the creatures to locate certain of their prey by feeling for it. In the large African otter the webs between the toes are greatly reduced, and the facial bristles or "whiskers" are much softer than those possessed by the common otter.
South America can boast of a very large otter, whose tail is wider and more flattened than is the case with the otters above mentioned. It will thus be seen that there are only slight differences between individuals composing the typical otters.
No. 1.
Otter's Rudder.
The common British otter (Lutra vulgaris) is known by a variety of names in this country. The Welsh call the animal dwrgi, while in Cornish it is written durgi. In the Highlands, where Gaelic is spoken, the name is dòbhran. The physical formation of the otter is admirably adapted to fit it for an aquatic existence. In order to offer the least possible resistance to the water when the animal is swimming below the surface, the otter's head and muzzle are flattened, and the ears are very small. Both ears and nostrils can be closed to exclude the water. The body is long, low, and sinuous in movement, set upon short legs which are loosely articulated. The feet are palmate, with five toes armed with short, non-retractile claws, and perfect interdigital webs. The tail is more than half the length of the head and body, broad at the base, and horizontally flattened. Beneath the root of the tail will be found a pair of small glands containing a fetid liquid secretion. Being an aquatic, sub-Arctic species, the otter is furnished with a body covering of two kinds. The thick, close under-fur, which attains special luxuriance of growth, is provided for two purposes, i.e., for keeping out the wet when the animal is in the water, and for preventing loss of heat during cold weather. Overlying this under-coat is a covering of longer hairs, which are stiffer and more shiny, greyish in colour at the base, and brown at the tips. This dark colouring shows in most pronounced fashion on the upper portions of the body, and on the outer surfaces of the legs and shoulders. The inner portions of the legs, belly, chest, throat, and cheeks are brownish-grey. The throat often shows a good deal of white or greyish-white in irregular patches. This, however, varies considerably in individual specimens, some showing a good deal of it, others practically none at all. Turning again to the head, we find the eyes small and dark coloured, while the so-called "whiskers" are long, stiff, and thick at the base. These long, stiff hairs grow on the upper-lip, and there is a tuft of them over each eye, and two tufts—one below the other—on each cheek. In the case of the domestic cat these "whiskers" are soft, and possess a very delicate sense of touch, thus enabling the animal to creep noiselessly through undergrowth in pursuit of prey. Should the cat's "whiskers" touch the grass or other growth on each side, puss is then instinctively aware that there is not sufficient room for her body to pass, and that she will therefore make a rustling sound if she persists in her advance, and so alarm her prey. These soft hairs on the cat's face are quite adequate for her purpose, because she hunts on land and hates wet. Soaked with water the soft hairs would droop and prove useless, and so it is for this reason that the otter's "whiskers" have gradually developed until now they are strong and stiff in order to withstand the exigencies of frequent underwater journeys. They are used, too, in a rather different way, for although while on land they may aid the otter to make a quiet approach on prey, their chief purpose is for locating food—in the shape of frogs, fish, etc.—either beneath stones, or on the bottom of the riverbed. The long hairs on the otter's upper-lip are susceptible of considerable movement, for their development has been followed by that of the muscles beneath, which give the puffy appearance to the otter's face. Provided with perfect interdigital webs on all four feet, the otter when swimming slowly, paddles in exactly the same manner as a dog. When the speed is increased, however, the tail is brought into action, being moved from side to side, while the body is thrown into sinuous curves.