82 THE FUR SEALS OF THE PRIBILOF ISLANDS. 



Thus, on the deadly sands of Tolstoi, where during the rookery season of 1896 there 

 appeared to be not over 120 bodies, a complete count showed 1,493, while on the flat 

 portion of Polovina, where 584 dead pups were found, Professor Thompson and myself 

 on July 23 could see only 8. 



Then, too, in many places the bodies of the dead rapidly disintegrate and disap- 

 pear. Gulls begin the scavenger work, flies and foxes continue it, and rain and wind 

 sweep up what remains; or in the denser portion of the rookery grounds the grind- 

 ing of hundreds of flippers and the drifting sand soon remove all traces of the dead, 

 and in a few months a scattered bone or two, which will serve as playthings for next 

 year's pups, is all that remains to tell the tale. So quickly do the bodies disappear 

 when the conditions are favorable that by October 10, 1896, not 10 per cent of the 

 dead counted during the first half of August could be recognized. 



Now and then, however, some traces of the former destruction of pups comes to 

 light, as in 1896, when a dry October gale swept over St. Paul, removing the sand 

 in places to a considerable depth, laying bare the bones of numberless pups, long 

 buried in the sand flat of Tolstoi. Here, where a short time before only a bone or two 

 was visible, fragments of 336 skulls were counted in a space of 39 by 42 feet, while 

 the area adjoining the present terminus of the rookery showed even more. ' 



In one of the gullies at Zapadni there were 27 skulls, or rather fragments repre- 

 senting that number, in one little pile, but here they had washed together from various 

 places above, and the local mortality, although great, was not so bad as it might at 

 first appear. 



As previously noted, the plague of Uncinaria ceases about the end of August, 

 and its cessation appears to bear a direct relation to the habits of the pups, who by 

 that time pass more or less of their time in the water, where the fseces are for the 

 most part voided. The embryos of Uncinaria therefore pass into the water and perish 

 instead of falling on the ground, where they may readily be taken up by the seals. 



The rains of fall and the intense cold of winter must kill any Uncinaria which 

 may linger in the sand, and we do not yet know how the rookeries become reinfected 

 in the spring, although it is very probable that the older seals are to some extent 

 troubled with the parasite, and that it is through their agency that the disease is 

 started anew. This, however, is merely surmise, for the examination of a number of 

 bachelors and old bulls failed to reveal the presence of any Uncinaria. The rapid 

 digestion of the older seals and, above all, the fact that their food is obtained in the 

 water and at great distances from land are factors of safety for them. 



Next to Uncinaria the most frequent cause of death among young seals is starva- 

 tion, and while the ratio shown in the number dissected may not be found in the total 

 number of deaths, there is some reason to suspect that such may be the case; and, in 

 any event, starvation is an important source of loss. If we use the figures obtained 

 by Mr. Snodgrass from an examination of 75 young seals on St. George, and apply 

 them to the total aumber of pups found dead in August, 1896, we would have 617 of 

 the 735 deaths on St. George due to starvation, a death rate of 30.8 per 1,000, according 

 to the estimates of the number of female seals on St. George in 1896. As starvation 

 is the cause of the vast majority of deaths on St. George, it is fair to assume that this 

 is not far from the normal ratio. Applying this ratio to the 123,000 females estimated 

 to have been on St. Paul in 1896 would give 3,800 pups as having died from starvation 



^Recorded by Mr, Clark, 



