FUR SEALS AND OTHER LIFE, PRIBILOF ISLANDS, 1914. 59 



and the bulls or males of 7 years and over. The classes of females are the pups, the 

 yearlings, the virgin cows or 2-year olds, and the bearing cows or cows of 3 years and 

 over. The distinction of these various classes is a matter of great importance in the 

 study of the seals and in the practical management of the herd. It is especially important 

 to distinguish the bachelors of 2, 3, and 4 years since these are the classes most similar 

 in general appearance and the ones from which quotas and reserves must be taken. The 

 other classes are mostly so easily distinguished as to require no special discussion. 



GENERAL DISTINCTIONS. 



Certain obvious general distinctions have long been recognized. Thus, the males 

 after the third year are so much larger than an}- female that no confusion is possible. 

 Males and females of 2 and 3 years, although distinguishable by a combination of minor 

 characteristics which are apparent to the experienced obsener, have a general similar- 

 ity in size and color, but they are so completely segregated during the kiUing season 

 prior to August i that no attempt at careful examination of individuals is necessary. 

 The cows keep strictly to the breeding areas during the early part of the season and 

 the bachelors to the hauling grounds with such rare exceptions that they need not be 

 considered. Pups or yearlings of both sexes, so far as known, are identical in general 

 appearance, but the males and females can be readily distinguished when handled. 

 The skinner is always aware of the sex of any seal of any age the moment he takes it 

 in hand to make the opening cuts. Cows or bulls of advanced age are easily distin- 

 guished from those of the early years of maturity, but the exact age of a given indi- 

 vidual can not be known except in a few cases, and it is of no practical importance that 

 it should be. Pups in their first season are distinctly characterized by color, though, 

 as noted elsewhere, they may become so fat at 3 months of age as to weigh quite as 

 much or more than yearlings. Bachelors in the fifth year develop the "wig" or mane, 

 which ser\'es as a mark of recognition in addition to increased size. The bachelors of 

 2, 3, and 4 years, however, are \'ery similar in all general respects, and can be distin- 

 guished onlv bv size. 



SPECIAL METHODS APPUED IN 1914. 



Heretofore bachelors of certain average size have been regarded as 2 -year-olds, 

 those of the next size as 3-year-olds, and those of the next as 4-year-olds. Certain seals 

 actually or apparently intermediate between the more or less vague standards have 

 been classified as "long 2 -year-olds," "short threes," or b)^ similar tenns. The actual 

 age of any particular seal was never known with certainty, since no seals had been 

 marked at birth and subsequently measured as they reached different ages. In 191 4 

 it was possible for the first time to measure seals positively known to be 2 -year-olds, 

 since a number of that age were present bearing distinctive brands placed upon them as 

 pups in 1912. With these 2-year-olds as a standard of comparison it was possible to 

 determine the characteristics of the 3-year-olds and the 4-year-olds. As a further and 

 very important check upon the conclusions a large number of skulls were preser\'ed, 

 furnishing unmistakable evidence of the relative age of different individuals. Further- 

 more, the standard of distinction adopted has been the one subject to the least variation, 

 namely, the total length of the animal. It has long been recognized by zoologists and 

 students of classification and variation that the total length measurement of mammals 

 is the most constant and reliable one that can be taken. This dimension is not affected 



