The Otariæ appear to make periodical migrations towards the south; and the Sea-lions (O. jubata) come to the Falkland Islands in November, where they remain till June or July, when the greater number depart; but some remain there the whole year round (P. Z. S. 1869, p. 108).
Navigators, from the general external resemblance of the animals, have regarded the Sea-lion and Sea-bear of the northern and southern regions as the same animal. Pennant (who paid considerable attention to Seals) and most modern zoologists have done the same.
Nilsson, in his excellent Monograph of the Seals, only mentions three species of Eared Seal:—1, Otaria jubata; 2, O. ursina; and, 3, O. australis. He believed that the first was common to the Falkland Islands, Chile, Brazil, New Holland, and Kamtschatka, and the second to Magellan’s Straits, Patagonia, New Holland, and the Cape. We now know that the species have a very limited geographical distribution.
When I published my ‘Catalogue of the Seals in the British Museum,’ in 1850, I was satisfied from Steller’s description that the species he described from the Arctic regions were distinct from those found in the Southern seas; and when I at last succeeded in obtaining specimens and skulls from the northern regions of the Pacific, I not only found that my idea was confirmed, but that they did not even belong to the same genera. I had the skulls of these species figured in the ‘Proceedings of the Zoological Society’ for 1859, and this greatly extended the knowledge of the animals. But there is yet much to be learnt respecting them. We do not know the species of Fur-seal described by Forster as inhabiting the coast of New Zealand.
The skull of these animals changes so much in form as the animal arrives at adult and old age that it is not always easy to determine the species by it, unless you have a series of them, of different ages and states, to compare. Thus Dr. Peters, in his revision of the genus after the publication of my Catalogue and figures of the skulls in the ‘Voyage of the Erebus and Terror’ and in the ‘Proceedings of the Zoological Society,’ formed no less than five species from the skulls of the southern Sea-lion (Otaria jubata)—O. jubata, O. Byronia, O. leonina, O. Godeffroyi, and O. Ulloæ,—referring the first four to the subgenus Otaria, and the last to Phocarctos (see Monatsbericht, May 1866, pp. 265, 270). In his second essay, published a few months later (ibid. Nov. 1866), after his visit to London, he placed them all together in one subgenus (Otaria), and seems, by the way in which he has numbered four of them, to doubt their distinctness. It would have been better if he had at once simply reduced them to synonyms (as they must be reduced) and included with them O. Ulloæ, which is only the skull of a young specimen, such as was called O. molossina by Lesson and Garnet. I may observe that I had shown in my first ‘Catalogue of Seals’ (1850), from the examination of the typical skull, that two or three of these nominal species were only very old or young skulls of the southern Sea-lion.
It is the character of the Eared Seals or Otariadæ to have a very close, soft under-fur between the roots of the longer and more rigid hairs. They are therefore called Fur-Seals by the sealers, and are hunted for their skin as well as for their oil. The quantity and fineness of the under-fur differ in the various species; and the skin and under-fur bear a price in the market according to the country and the species from which they are obtained.
Some species of the family have so little under-fur when they arrive at adult age, that they are of no value in the market to be made into “seal-skins;” these are therefore called Hair-Seals by the sealers. They are only collected for the oil, as the skins are of comparatively little value.
The skins of the Fur-Seal are much used in China, and are more or less the fashion in this country, sometimes being far more expensive than at others. The skins of the Hair-Seals are only used, like the skins of the Earless Seals or Phocidæ, for very inferior purposes, as covering boxes, knapsacks, &c.; but the animals are much sought after for the oil they afford.
The furs of the different species of Fur-Seals are exceedingly different in external appearance, especially in the younger specimens, or when the fur is in its most perfect condition. In most species the hairs are much longer than the under-fur; they are flat and more or less rigid and crisp. In others the hairs are short, much softer, scarcely longer than the soft woolly under-fur; in these species the fur is very dense, standing nearly erect from the skin, forming a very soft elastic coat, as in O. falklandicus and O. Stelleri.
The hair of O. nigrescens is considerably longer than that of O. cinerea, but not so harsh, the fur of the half-grown O. nigrescens being longer, sparse, flat, rather curled at the end, giving a crispness to the feel; while the hairs of the very young specimens are abundant, nearly of equal length, forming an even coat that is soft and smooth to the touch.