HABITS. 227 



times that of the adult females of the same species. There 

 are also very great differences in the form of the skull, espe- 

 cially in respect to the development of crests and protuberances 

 for muscular attachment, these being only slightly developed 

 in females and enormously so in the males. With such remark- 

 able variations in color and cranial characters, dependent upon 

 age and sex, it is not a matter of surprise that many nominal 

 species have arisen through a niisappreciation of the real signifi- 

 cance of these differences.* 



HABITS. 



The Eared Seals show also a remarkable resemblance in their 

 gregarious and polygamous habits. All the species, wherever 

 occurring, like the Walruses and Sea Elephants, resort in 

 great numbers to particular breeding stations, which, in seal- 

 ers' parlance, have acquired the strangely inappropriate name 

 of " rookeries." The older males arrive first at the breeding- 

 grounds, where they immediately select their stations and await 

 the arrival of the females. They keep up a perpetual warfare 

 for their favorite sites, and afterward in defense of their harems. 

 The number of females acquired by the successful males varies 

 from a dozen to fifteen or more, which they guard with the utmost 

 jealousy, might being with them the law of right. The strong- 

 est males are naturally the most successful in gathering about 

 them large harems. The males, during the breeding season, 

 remain wholly on land, and they will suffer death rather than 

 leave their chosen spot. They thus sustain, for a period of sev- 

 eral wee*ks, an uninterrupted fast. They arrive at the breeding 

 stations fat and vigorous, and leave them weak and emaciated, 

 having been nourished through their long period of fasting 

 wholly by the fat of their own bodies. The females remain 

 uninterruptedly on land for a much shorter period, but for a con- 

 siderable time after their arrival do not leave the harems. The 

 detailed account given a century ago by Steller, and recently con- 

 firmed by Bryant and Elliott, of the habits of the northern Fur 

 and Hair Seals during the breeding season, is well known to 

 apply, in greater or less detail, to nearly all the species of the 

 family, and presumably to all. As the observations by Messrs. 

 Elliott and Bryant are presented later in this work at length, it 

 is unnecessary to give further.details in the present connection. 



*Of about fifty synonyms pertaining to the Eared Seals, probably two-thirds 

 have been based, directly or indirectly, upon differences dependent on sex and 

 age, and the rest upon the defective descriptions of these animals by travellers. 



