"Den sign" means indications of denning activity and should always be watched for. It may consist of tracks, a well-worn path leading to and from a den, or holes freshly cleaned out. Holes made by the coyotes in digging out squirrels or rabbits should not be confused, however, with those prepared for dens. A good hunter will overlook no likely place and should take advantage of every hint, for dens are often found where least expected. He should look for den sign in every locality where animals are frequently seen. He should keep in mind the places used by pairs of coyotes and visit all old dens known, as sign may often be discovered there at whelping time. Holes may be cleaned out in one canyon and the den be just over the hill in another. Sheep herders on a range usually can give valuable information as to locations of dens. The equipment of a den hunter should include at least two good, gentle saddle horses, a small shovel, a pair of good field glasses, a rifle of not less than .25 caliber, and a dog. Coyotes are not so much afraid of a man on horseback as of one on foot. A rider, therefore, can get many good shots, and in heavy sagebrush he can more easily see and track coyotes from his vantage seat upon a horse. Breeding Habits and Number of Young In the mating season coyotes may be heard yelping much more than usual, and packs of three to a dozen animals may be seen. Later the breeding animals pair off. Some pairs may remain together for a number of years, but as a rule coyotes do not mate for life. The whelping season varies with latitude. In general, according to studies of a large number of embryos by G. W. D. Hamlett, of the Biological Survey, the season in the northern tier of States seems somewhat earlier than farther south; in Montana, for example, breeding begins about February 1 and lasts throughout the month, the average date being February 15. In Texas, breeding seems to begin somewhat later, although data are inadequate for definite conclusions. In some States, as in Oregon and Arizona, Hamlett found a variation of at least 2 months in the time of breeding, probably because of great diversity in habitat. A study on the spot, with due attention to altitude and other environmental factors, would probably explain any unusual variation. Coyote pups are born 60 to 63 days after breeding. Their eyes open when they are 9 to 14 days old. The average number of young to the litter is normally 7. Although there may be smaller litters when food is scarce, it is not uncommon to find litters of 9 to 12 (fig. 1, A), and some females have been known to have as many as 17 young. The only thing provided in the nature of a nest is an enlarged section of the den, and some dens do not have even this. The pups lie in the dry dust on the floor.