The True Seals are divided by Dr. Gray into thirteen genera with eighteen species, of which the Common Seal, the Ringed Seal, the Harp Seal, the Grey Seal, the Sea Leopard, the Sea Elephant, and the Bladder-nose Hooded Seal are the best known. The common seal has a round head which in front bears some resemblance to that of the otter. Its average length is about five feet and its general colour of a yellowish gray, varied or spotted with brown or blackish in different degrees, according to the age of the animal. The Common Seal frequents the sea-coasts perhaps throughout the world, but is most numerous in high northern latitudes, and furnishes the inhabitants of those frigid regions with nearly all their necessaries and luxuries. Enormous numbers are caught annually for the sake of their skins and oil. The Harp Seal frequents the coast of Newfoundland and is so named from the harp-shaped band which marks the backs of the males. The Sea Elephant is the largest of the seals. It is said to attain to the length of twenty-five to thirty feet, and a circumference of fifteen to eighteen feet. It belongs to the Antarctic sea.
"Seals when taken young," says Captain Brown, "are capable of being completely domesticated, will answer to their name, and follow their master from place to place. In January, 1819, a gentleman, in the neighbourhood of Burnt-island, county of Fife, in Scotland, completely succeeded in taming a seal. Its singularities attracted the curiosity of strangers daily. It appeared to possess all the sagacity of a dog, lived in its master's house, and ate from his hand. In his fishing excursions, this gentleman generally took it with him, when it afforded no small entertainment. If thrown into the water, it would follow for miles the track of the boat; and although thrust back by the oars, it never relinquished its purpose. Indeed, it struggled so hard to regain its seat, that one would imagine its fondness for its master had entirely overcome the natural predilection for its native element."
Notwithstanding the absence of external ears the common seal has a remarkable sense of hearing and a keen taste for sweet sounds. Seals have been known to follow a vessel, for miles, upon the deck of which a violin or a flute has been played. To quote Sir Walter Scott: