find that those of the Orkney and Shetland Islands are the largest on our coasts,
if not in the world. Adult males in Great Britain measure from 4^ feet to
6 feet in length to the end of the tail, adult females from 3 ft. 6 in. to 6 feet.
Males weigh from 9 to 16 stones, and females from 50 lbs. to 12 stones.
As the dimensions of Common Seals are not well known, I append a short
table of weights and measurements taken from adult animals shot by Mr. Sidney
Steel and myself.
I Length from
Length from
Circumference
Sex
nose to end
nose to end
behind front-
Weight
Locality of tail
of back-
complete Date Owner
flippers
flippers
Female .
ft in.
6 4
ft. in.
6 10
». st. lbs.
Shetlands August 1899 J. S. Steel*
6 0 6 8 48 16 I Shetlands August 1901 J. G. Millais 3- 5 9 6 4 46 14 10 N. Uist August 1898 J. G. Millais 4 - 5 8* 6 I Orkneys J. S. Steel
6. 5 » 6 3 40 N. Uist August 1898 J. G. Millais
5 6 6 40 Shetlands August 1901 J. G. Millais 7- S 6 6 2 39 Shetlands August 1901
Male 5 4 5 8 Orkneys J. S. Steel
9- S 0 msm/n 1 37 Shetlands August 1901 J. G. Millais
5 « 5 7 126 N. Uist September 1897 J. G. Millais 4 10, S 3 35 Shetlands August 1901 J. G. Millais
Female . 4 I 4 5 N. Uist September 1897 J. G. Millais
Female . . 3 4 2 29 6 5 Shetlands August 1901 J. G. Millais &
* This is the largest Common Seal I have seen or measured.
Dr. J. A. Allen has pointed out1 that the sexes may be readily distinguished
by their teeth. In the male the teeth are relatively large, implanted very obliquely
in the jaws, and usually furnished with a number of small accessory cusps on
both the inner and outer edges. The females, he says, have teeth about one-half
smaller, implanted less obliquely, and they are furnished with fewer accessory
cusps, those on the inner side being almost invariably wanting. Since Dr. Allen
published his paper I have examined a large number of skulls of British Seals,
and though in the main I think that Dr. Allen’s conclusions are correct, certain
females possess teeth which cannot properly be distinguished, from those of the
males, and thus the test is by no means a certain means of determining sex.
When adult it is not difficult to distinguish between the crania of the
Common and of the Ringed Seal, although in the immature stages they are
1 * A Memoir on the True Seals of the North Pacific Ocean and Bering Sea,’ by Dr. J. A. Allen. Bulletin o f the
American Museum o f Natural History, December 1902.