SPECIAL INVESTIGATION OF THE ALASKA FUR-SEAL 

 ROOKERIES, 1910. 



By Harold Heath, 



Professor of Invertebrate Zoology, Stanford University. 



Under the act of Congress of April 21, 1910, involving various 

 changes in the administration of the Pribilof Islands and the seal 

 fisheries and providing for the appointment of additional officers 

 and employees, it was decided that a naturalist should be designated 

 to study and report upon the condition of the seal herd. Pending 

 the selection of a permanent occupant of this position, to take effect 

 July 1 under the law, the writer was sent to the islands as a special 

 investigator to perform the naturalist's duties for the season which 

 was already beginning. Observations were made on St. Paul Island, 

 beginning June 29, the date of arrival on the island, and continuing 

 until July 15, then for a week on St. George Island, and again on St. 

 Paul until August 29. A report of these observations is contained 

 in the following pages. 



I am indebted to the Government agents on the islands and to the 

 officers of the revenue fleet for valuable data and many courtesies 

 in connection with my work. 



BRIEF SKETCH OF NATURAL HISTORY OF THE SEAL. 



As popularly applied the term "seal" includes a fairly large group 

 of aquatic mammals, such as the sea lion and the fur and hair seals, 

 all of which bear a superficial resemblance to each other. Strictly 

 speaking, the last named are the only ones deserving of the name. 

 Unlike the hah- seal, the fur seal, or sea bear, is able to progress 

 readily on land, is able to hold its head erect, and its fore limbs, finlike 

 in form, are used in swimming. Concerning its life at sea, we know 

 that the seals of the Pribilof Islands spend their winter months along 

 the western coast of North America, the adult females extending their 

 migrations as far as southern California. Early in May the adult 

 males or bulls begin to appear on the rookeries, where each is sub- 

 sec inently joined by 30 females on the average, the height of the 



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