July 15, 1911] 



NATURE 



47 



small fraction of the numbers that were massed there 

 during living and even recent memory. 



The life-history of the fur seals is, very briefly, as 

 follows. The males grow to a great age and size, 

 wholly disproportionate to that of the small and 

 slender females; and this difference is, as usual, 

 .accompanied by the habit of polygamy. The old males 

 arrive upon the breeding-grounds in May, some weeks 

 earlier than the females, and take up their quarters on 

 the rough beaches, generally on some prominent slab 

 of rock ; here they doze and sleep until the arrival of 

 the females, who, heavy with young, slip quietly into 

 their places in the harems. The birth of the young 

 follows almost immediately, and soon afterwards the 

 comparative quiet of the rookery is exchanged for a 

 babel of noise and incessant quarrelling. The old 

 bulls in possession of neighbouring harems contend 

 with one another for the females, and the younger 

 bulls, as yet wifeless, strive continually to carry off 

 a straying cow, or dash into a harem when its owner 

 has wandered a few yards away. Moreover, the old 

 bulls are now in perpetual activity, rounding up their 

 harems, hastening after errant cows, quarrelling with 

 their neighbours, or engaging in fierce combat with 

 the "idle" and predatory bulls. So all day long the 

 noise of battle rolls along the beaches by the wintry 

 sea, and the growling and the snarling, the confusion 

 and the din, are for some weeks 

 together indescribable. 



The harems vary very much in 

 numbers, fifty cows being not un- 

 common, while a hundred, or even 

 more, have been occasionally re- 

 corded; but their numbers depend 

 upon the prosperity of the herd, 

 and fifteen years ago the average ' r .: 



number seemed to be rather under .*•' ,' 



twenty. The young males, or 49^B 



bachelors, from one to three or four 

 years old, arrive about the same ,. .' 



time as the females, but herd apart *>■ 



on grounds remote from those occu- 

 pied by the breeding herd. The 

 females and these young males go 

 down to the sea to feed, but the 

 old males starve rather than leave 

 their posts; they come fat and 

 vigorous in springtime, and are 

 gaunt, emaciated, and scarred with 

 the scars of many battles before 

 they leave again in autumn. This 

 family life, and the type of rocky 

 coast resorted to by the herds, 

 seems to vary little in the 

 different species, and a photograph of the herd 

 upon Lobos Island, for instance, is scarcely, if 

 at all, distinguishable from one taken on the Pri- 

 bylovs. At Guadalupe, however, by reason of the 

 tropical heat, the seals resort to the dark volcanic 

 caves that surround its coast-line, and to the same 

 cause perhaps is due the thinner and very inferior 

 quality of the fur, as compared with that of the 

 northern species. 



The old bulls display surprising agility, in spite of 

 their bulk and clumsy form, climbing over the rough 

 rocks and boulders in a wonderful way; and, in 

 general, as is well known, these eared seals can 

 waddle on their long, flapping flippers with 

 greater activity and over much longer distances than 

 might be expected. It was formerly the custom on 

 the Commander Islands to drive the bachelor seals 

 from the "hauling grounds" to the place of slaughter 

 a distance of at least three miles up and down a 

 rough mountain path. But Dr. L. Stejneger was 

 NO. 2176, VOL. 8/] 



once witness of a more remarkable case. Climbing 

 to the top of a rocky mountain on Copper Island, 

 certainly not less, if Trecollect rightly, than 2000 feet 

 high, he heard, as he reached up to the last rocky 

 summit, an angry growl, and there, to his amaze- 

 ment, was a great old bull seal, and the beast was 

 blind ! 



On the polygamous habits of the species, on the 

 segregation of the young males, and on the super- 

 fluity of the latter (for both sexes being born in 

 approximately equal numbers, a very large proportion 

 of the males are destined to perish in the struggle for 

 existence)— on these characters are based the practical 

 methods for the conservation of the herd. The 

 Government lessees kill the young bachelors only, by 

 preference those of three years old, leaving what they 

 consider a reasonable proportion to replenish the stock. 

 It is generally agreed that on the American Islands 

 this operation has always been conducted with reason- 

 able care and moderation, and with no more cruelty 

 than is implied in the rapid and skilful slaughter of 

 a large number of defenceless creatures. But the 

 other dangers to which the herds are exposed are 

 neither selective nor in any way conservative. The 

 pelagic sealer when at work around the islands kills 

 not only the young males, but in still greater numbers 

 the females of all ages, and it is certain that many 



f \ 



A Rookery Courtship on the Pribytovs. (From Nature, by Bristow Adams, in the 

 American Commission's Report, 1896-7.) 



pups on shore must in consequence perish of starva- 

 tion ; while the raider who lands upon the rookeries 

 kills all and sundry, young and old, in one spell of 

 merciless destruction. Nor is the seal altogether 

 immune from natural causes of mortality, apart from 

 old age and from the attacks of man ; but though the 

 grampus, for instance, now and then devours him at 

 sea, there is only one known cause of mortality that 

 is apparently serious. In warm countries a very con- 

 siderable number of puppies die owing to the attacks 

 of a species of Ankylostoma, a tiny nematode worm, 

 the eggs of which lie among the earth and sand, and 

 in one way or another are swallowed by the pup ; and 

 a species of the same dangerous parasite is found 

 abundantly in the bodies of the many dead seal-pups 

 that towards the end of the season are found lying 

 upon the rookeries, and apparently in greater numbers 

 on the more sandy and less rocky of these. 



But whatever part this parasite or other accidents 

 may play as causes of mortality, it is certain that 



