INTRODUCTION 
In this paper we review experiments in the marking, for study purposes, 
of seals, sea-lions, and fur seals in the North Atlantic, North Pacific, and 
Antarctic regions. We also discuss the results of certain studies of the 
northern fur seal, especially the series from 1940 to 1949 carried out by 
Government agents on the Pribilof Islands, Alaska, 
REVIEW OF MARKING METHODS 
Clipping, northern fur seat (Callorhinus ursinus), Alaska.=The spectacle 
of a on rur seals res on the shores o e of islands has 
evidently been to biologists ani irresistible temptation to mark one from the 
other. Thus, to date, about 150,000 seals have been singled out and marked 
by brand or other device. 
(1) At some time in the last century, probably in the 1860's, the 
Russian owners of the Pribilof Islands "drove up a number of young males 
from Lukanon, cut off their ears, and turned them out to sea again, The 
following season, when the droves came in from the 'hauling-grounds' to the 
slaughtering-fields, quite a number of those cropped Seals were in the drives" 
(Goode 1884: 77). 
(2) In 1870, two years after the purchase of Alaska by the United 
States, Captain Charles Bryant clipped the ears of 200 seal pups on St. Paul 
Island. On pups from Lukanin Rookery he clipped the right ear, and on pups 
from Reef, the left. He was trying to prove or disprove the theory that seals 
always return to the island and rookery of their birth. He repeated the 
experiment in 1871. Marked seals were killed in 1872 and 1873 in sufficient 
numbers to disprove the theory (U. S. Treasury Dept. 1898(1):29; 38, and 41). 
Better evidence on the wandering of seals has been gathered since the 
time of Bryant. His early experiment is still of interest, however, because 
it suggests that ear clipping, or ear tagging, is a practical way to mark 
seals, The animals are usually seen in a compact group on the summering 
grounds. In crowded formation most of the body is hidden and only the head 
and ears are conspicuous. From the standpoint of recovering specimens, the 
advantages of marking a prominent feature are obvious. On the other hand, 
the ear of a seal is a delicate valve-like organ. By excluding water it 
allows the seal to dive to depths of 240 feet or more. Scar tissue resulting 
from an injury to the ear might lead to the death of the animal. We have 
refrained from using the ear-clipping technique during the modern era of 
research on the Pribilof Islands. 
(3) The ear tips of 1,000 seals about three years old were removed in 
the summer of 1924 (Bower 1925: 149). The operation was presumably done with 
wool shears, since the animals were said to have been sheared as well. The 
results of the experiment are not recorded. 
Branding, northern fur seal, Alaska (table 1).--(1) Branding was carried 
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