EARLESS SEALS. 133 
up to breathe. According to Dr. Robert Brown, the average time of a seal’s 
submergence is from five to eight minutes, while the limit is set down by the same 
observer, at a quarter of an hour. Other authorities state, however, that the time 
may be extended to as much as twenty or thirty minutes. The sounds uttered by 
seals are various, in some cases taking the form of a kind of barking note, while in 
others they assume a more bleating tone, or even resemble the ery of a child; the 
note of the young being always more plaintive and Jess hoarse than that of the adult. 
In no cases, however, do they utter barking roars comparable to those characteristic 
of the eared seals. 
The strange circumstance that young seals take to the water reluctantly, and 
have to be taught the art of swimming by their parents, would alone appear to be 
a sufficient indication that seals are originally descended from land Carnivores. 
Among some species the young remain entirely on the land or the ice for the first 
two or three weeks of their existence, or until they have shed their first coat of 
woolly hair. Numbers of seals are destroyed by the Polar bear, while others fall 
victims to the rapacious killer-whale. Others again are frequently destroyed by 
being jammed between ice-floes; and it is stated that thousands are sometimes 
killed by this means. The reduction in their numbers by all these causes are, 
however, trivial compared to those inflicted by man, who, according to Mr. J. A. 
Allen, requires about a million and a half to supply his annual needs. So reckless, 
indeed, has been the destruction of seals, that some species are already well nigh 
exterminated, while others have been so reduced in numbers as to render their 
pursuit no longer profitable. 
Several species of seals inhabiting the Northern Hemisphere are in the habit of 
making long migrations, moving southward to avoid the intense cold of winter, 
and returning northward in summer; such migrations being most marked in the 
Greenland and the hooded seal. These movements have been carefully observed 
by Mr. J. C. Stevenson, on the Atlantic coasts of North America. The southern 
migration commences soon after the frost sets in; and at this season, he writes, 
“a fisherman, posted as sentinel on some headland commanding an extensive 
sea-view, communicates to the hamlet the first indication of the approaching 
host, the vanguard of which invariably consists of small detachments of from 
half a dozen to a score of seals. Such parties continue to pass at intervals, gradu- 
ally increasing in frequency and numbers during the first two or three days of 
the exodus, by the end of which time they are seen in companies of one or more 
hundreds. The main body is now at hand, and during the greater part of the next 
two days one continuous uncountable crowd is constantly in sight. The whole 
procession coasts along at no great distance from the shore, presenting to an eye- 
witness a most extraordinary scene. In all quarters, as far as the eye can carry, 
nothing is visible but seals—the sea seems paved with their heads.” 
From the conformation of their hind-limbs, the true seals are unable to progress 
on land in the manner characteristic of the eared seals and the walrus; both the 
latter being able to bring their hind-limbs under the body by arching the back and 
carrying forward the hind-feet by a kind of jerk. Very generally the true seals 
move on land merely by a kind of wriggling motion of the body, with the fore- 
limbs held close to the sides of the trunk and the hind-limbs stretched out straight 
