MAEMOT 161 



feeder than are the other members of the squirrel family. But individuals 

 inhabiting the rock slides must either depend, in company with the Bushy- 

 tailed Wood Rat and the Yovsemite Cony, upon the plant growths, such 

 as the red elder-berry, which occur among the rocks, or else venture out 

 some distance to vegetation growing in the open. 



A feature yet to be mentioned for the majority of marmot burrows is 

 the presence close by, of a flat-topped rock on which the animal can sprawl 

 out to bask in the sunshine, while at the same time keeping watch for the 

 approach of enemies. Specially chosen rocks, used for the same purpose, 

 are to be seen in the case of marmots which live in rock slides. On many 

 of these rocks are large accumulations of droppings indicating occupancy 

 through several successive seasons. (See pi. 32h.) Likewise the smooth 

 worn condition of many of the burrows, the absence of accumulations of 

 earth about the entrances, and the lack of grasses and other plants there, 

 all suggest that those locations have been in use for a number of years. 



The food of the marmot consists of green vegetation including various 

 herbaceous plants and grasses. The animal possesses no internal cheek 

 pouches as do the ground squirrels and it is not known to store up a supply 

 of food for winter use as does the cony. The lesser nutritive value of 

 grasses as compared with seeds (used extensively by the squirrels) requires 

 the marmot to take relatively large quantities of the former — and this it 

 does, day after day, throughout the summer season. When the marmots 

 emerge in the spring they are quite lean. As soon as green vegetation is 

 available they feed to repletion, spending the daylight hours between suc- 

 cessive feedings simply resting. This process results in a rapid accumulation 

 of fat, which tills every space in the body and lies in great layers between 

 the skin and muscle. This fat serves a double purpose ; during the hiber- 

 nating period it acts as an insulating layer to conserve bodily heat and also 

 as fuel to maintain the life processes which are carried on, though at a 

 lowered rate, during the period of dormancy. 



The behavior of the species is indicated by the following account, 

 written in the field after one of us had been watching a marmot for a half- 

 hour or more at the head of Lyell Caiion one day in mid- July (the 20th, 

 1915). 



The animal when first sighted had been feeding in meadow grass, but it took fright 

 at my approach and ran to the shelter of a rock pile. By moving slowly, I was able 

 eventually to get within 15 feet of it and to take several pictures. The animal would 

 move out on some flat-topped rock, remain there for a time with occasional slight changes 

 of posture, and then disappear into the slide, to reappear soon at another similar location. 

 Certain rocks seemed to be used as regular resting places, for the Marmot seemed inclined 

 to stay about these. Often, although not always, the post taken was a slanting rock 

 from which the animal could quickly tumble down into the interstices of the slide at the 

 first intimation of danger. Once, for a short time, it reared up on its hind legs, using 

 the tail to help support the body. Several times the Marmot uttered its sharp whistle, 



