The "ground hog" is often hunted for sport and sometimes for food. Near centers of human population the yellow-bellied marmots are extremely shy. Along the highways of the Columbia River on any Sunday in June, it is not unusual to see a dozen cars in an hour, moving slowly past a talus slide while eager hunters scan the rocks for marmots. In the late afternoon, when the marmots leave the protection of the talus slides to drink at the river, they fall easy prey to rifles with telescope sights. Near cities in eastern Washington yellow-bellied marmots have become partially nocturnal. Couch (1930: 2-6) attempted to excavate several dens of yellow-bellied marmots, but decided to leave the task "to some future road-building crew." Embryos found by Couch numbered three to six. Couch thought the young were born about March 15 in the Snake River area and about April 15 in the upper Okanogan area. The young appear above ground approximately 30 days after birth. The yellow-bellied marmots enter aestivation from late June to early August, depending on the locality and local conditions. They are active longer in northeastern Washington. Couch records a yellow-bellied marmot seen in Okanogan County on October 10, but regards this as exceptional. The marmots near Wenatchee, Chelan County, emerge from their burrows in early March (March 5 to 10, from reports of residents in 1937, 1938). Couch (1930: 5) gives February 20 to March 15 as the date of appearance. A principal requirement for marmots is the presence of rocks. At Cle Elum, Kittitas County, I took a marmot from an alfalfa field where a farmer had placed all the surface stones in a loose pile. Fifteen miles east of Tonasket, Okanogan County, marmots were living in the stones piled by road builders to support the ends of a small bridge. A hundred feet away another marmot was living under an abandoned building. A high, convenient rock near their burrow serves the yellow-bellied marmots as a look-out post. These look-out posts seem, in many cases, to have been used by many generations of marmots, for their feces sometimes fill nearby crevices to a depth of several feet and cover the look-out rock itself. The glacial boulders on the plateau between the Okanogan River and Omak Lake, Okanogan County, furnish the best examples of look-out posts. These numerous isolated boulders, ten to fifty feet in diameter and ten to thirty feet high, each seem to furnish shelter to one or more marmots. Well-worn trails lead from the boulders to burrows and feeding areas.