BELMULLET WHALING STATION. 145 
this would account for some pairings occurring at such times as the 
beginning of July or the beginning of May. 
Such cases would belong to the June and April cestra respectively. 
It is probable that such an arrangement would be advantageous. 
As the whale is a pelagic animal and individuals are widely separated, 
a frequently recurring breeding condition would be of great advantage to 
an animal in which pairing is to a greater or less extent casual. The 
above suggestion, which was originated by Mr. Daniel, appears to afford 
a possible explanation of the extraordinary variability in the sizes of the 
foetuses, apparently without regard to the season, a circumstance which 
the idea of a definite moncestrous cundition does not elucidate. (It is 
interesting to note that on June 18, 1918, at the Inishkea Station a 
feetus only 5 in. long was found, which must have been but a week or 
two old, i.e., of the June pairing, according to the preceding method 
of reckoning the pairing times. It was, most unfortunately, not possible 
to preserve it.) 
X.—Additional Notes. 
(a) Hatinction.—The whalemen state that of the whales which 
they see they are able to take only about one in ten. The animals 
are therefore perhaps not in immediate danger of being actually killed 
out. The most serious risk lies in the fact that the largest, and- 
therefore the adult, whales are being exterminated. True gives as the 
minimum length of adult animals 55 ft. 7 in., as no pregnant females of 
less dimensions have been recorded. Now the whalers will take any- 
thing over 40 ft., with the result that the animals which have attained 
sexual maturity are in the gravest*danger of being killed out. That the 
largest whales are being exterminated, the fall in general size at Blacksod 
between 1911 and 1913 may indicate. This means that the whales 
which are capable of reproduction are being destroyed. By the time 
that it is no longer profitable to hunt whales,'® it appears likely that the 
adults will have been so thinned out that they will no longer be able to 
reproduce with sufficient profusion to compensate for natural casualties. 
When this occurs the whales will be well within sight of extinction. 
(b) Capture of Blue Whales.—Of all the species which it is profit- 
able to pursue the whalers state that the Blue Whale is the wildest, 
and they will not hunt this species if other game is to be had. A 
Blue Whale on perceiving the pulsations of the propeller of the 
approaching steamer is usually startled, and, if alarmed, at once 
rushes off at full speed. Since this represents something like twenty 
miles per hour, it is quite useless for the boat to pursue the fleeing 
animal, the speed of the steamer being only ten or twelve miles per 
hour. When the whalers are bent on catching a Blue Whale, it is 
- sometimes necessary to accompany the animal for three or four days, 
until it becomes accustomed to the presence of the steamer, which can 
then approach within range, and the whale is speedily disillusioned as 
to the harmlessness of the now familiar object. 
(c) Migration Movements.—During the earlier part of the season 
the Mystacocetes are stated to travel in a north-easterly direction, 
* Burfield, op. cit., p. 153. 
1914. L 
