602 CARNITORA 
Although the members of this subfamily swim and dive 
with the greatest ease, often remaining as much as a quarter of 
an hour or more below the surface, and are dependent for 
their sustenance entirely on living prey captured in the water. 
vet they frequently resort to sandy beaches, rocks, or ice-floes, 
either to sleep or to bask in the sun, and especially for the purpose 
of bringing forth their young. The latter appears to be the 
universal habit, and, strange as it may seem, the young seals—of 
some species at least—take to the water at first very reluctantly, 
and have actually to be taught to swim by their parents. The 
number of young produced is usually one annually, though 
occasionally two. They are at first covered with a coat of very 
thick, soft, nearly white fur, and until it falls off they do not 
usually enter the water. This occurs in the Greenland and Gray 
Seal when from two to three weeks old, but in the Common Seal 
apparently much earlier. One of this species born in the London 
Zoological Gardens had shed its infantile woolly coat and was 
swimming and diving about in its pond within three hours after its 
birth. The movements of the true Seals upon the ground or ice 
are very different from those of the Eared-Seals. Thus the hinder 
limbs (by which mainly they propel themselves through the water) 
are on land always perfectly passive, stretched backwards, with the 
soles of the feet applied to each other, and often raised to avoid 
contact with the ground. Sometimes the fore limbs are equally 
passive, being placed close to the sides of the body, and motion is 
then effected by a shuffling or wriggling action produced by the 
muscles of the trunk. When, however, there is any necessity for 
a more rapid mode of progression the animals use the fore paws. 
either alternately or simultaneously, pressing the palmar surface 
on the ground and lifting and dragging the body forwards in a 
succession of short jumps. In this way they manage to move so 
fast that a man has to step out beyond a walk to keep up with 
them; but such rapid action costs considerable effort, and they 
very soon become heated and exhausted. These various modes of 
progression appear to be common to all species so far as has been 
observed. 
Most kinds of Seals are gregarious and congregate, especially at 
the breeding season, in immense herds. Such is the habit of the 
Greenland Seal (Phocu grwnlundica), which resorts in the spring to 
the ice-floes of the North Sea, around Jan Mayen Island, where 
about 200,000 are killed annually by the crews of the Seoteh, 
Dutch, and Norwegian sealing vessels. Others, like the Common 
Seal of the British islands (P. vitulina), though having a wide 
geographical range, are never met with in such large numbers or 
far away from land. This species is stationary all the vear round, 
but some have a regular season of migration, moving south in 
