FEEDING OF THE FUR SEALS. 55 



no more than a single day. In observing the rookeries the eye can not adjust itself 

 readily to the change, and the result is that the period seems to comprehend several 

 days. 



From about the 10th or 12th of June onward new cows are constantly arriving 

 on the rookeries. About ten or twelve days after her arrival each cow goes away to 

 feed for the first time. The first arrivals and first departures therefore run roughly in 

 parallel lines. A disturbing element is brought in by the return of cows from feeding 

 and their subsequent departure and return at intervals. All these various elements 

 result in a period of apparent equilibrium at about the 15th of July, which is the 

 height of the season. 



THE PERIOD CURRENTLY MISUNDERSTOOD. 



That this period of rookery development should have been misunderstood is not 

 strange, since the matter was never before tested by mathematical standards. 

 Events in rookery life, though recurring by the thousands, are difficult of observation. 

 Their very multitude distracts the observer. In the summer of 1897, at the maximum 

 period of rookery life, when thousands of pups were being born, the closest observa- 

 tions, extending at times through nine hours a day, failed to disclose the aetual 

 birth of more than a dozen pups. Under this same close scrutiny it was a week 

 after the first landing of cows before one could be discovered in the act, and a much 

 longer period elapsed before the departure of one could be observed. General 

 observations of the rookeries have therefore only relative value unless they are 

 checked by figures. They can be trusted to show large results, but can not be relied 

 upon to indicate normal changes. To get definite results, exact enumerations and 

 minute observations are necessary. 



THE BIRTH OF THE PUP. 



Within a period of from six to forty-eight hours after her arrival the cow gives 

 birth to her pup. After a further period of five to six days she comes in heat and is 

 served by the bull. Five to six more days pass, during which time the pup grows 

 rapidly and becomes able to take care of itself; then the mother goes to sea to 

 bathe and feed. Her first return is possibly within three or four days. Of her 

 subsequent returns no record has been possible, but from the gradual decrease in the 

 number of cows present after the height of the season is reached, it must be inferred 

 that the time of absence lengthens as the pup grows older and is able to remain 

 longer without food. As the cow does not leave the harem until after impregnation 

 it necessarily follows that adult cows whenever found at sea are pregnant. 



TEE FEEDING OF THE COWS. 



When the cows first enter the water after their long rest on the shore they exhibit 

 every evidence of genuine satisfaction and pleasure. They do not at once swim away, 

 but play about, rolling over and over in the water, scratching and rubbing themselves 

 with their flippers, getting thoroughly cleaned from the filth of the rookeries. This 

 done, the animals swim away to the feeding grounds. 



SWIMMING SEALS. 



During the breeding season a band of sleeping, playing, or swimming seals 

 skirts each rookery front. Some are plainly bachelors, but most are cows. This 



