Fig. 128. Distribution of the black-tailed jack rabbit, Lepus californicus deserticola, in Washington.
Black-tailed jack rabbits reach the northern limit of their distribution on the Columbian Plateau of eastern Washington. They extend from Washington south to the Valley of Mexico and from the Pacific Coast east to Missouri ([Nelson], 1909: 127). About 20 races are recognized, of which only one is native to Washington.
The blacktail is restricted to the Upper Sonoran Life-zone. Seldom is it found far from sagebrush (Artemisia) and rabbitbrush (Chrysothamus). It is well adapted to desert life, and is able to withstand the bitterly cold winters and hot, dry summers of eastern Washington. Blacktails are active in the evening, night, morning, and cooler parts of the day. In the daytime they crouch in forms consisting of shallow depressions at the bases of shrubs.
Blacktails eat the twigs and leaves of sagebrush, rabbitbrush, other desert shrubs, and grasses. They are particularly fond of alfalfa and cultivated crops, of which they destroy great quantities. They are serious pests during periodic years of abundance. Some measure of their abundance may be gained by counting the bodies of jack rabbits killed by cars on well-traveled highways through sagebrush areas. In years of abundance these may number 50 to 100 per mile, while in years of scarcity these may number only one or two.
Black-tailed jack rabbits are susceptible to numerous parasites and diseases including tularemia. Diseased rabbits are especially noticeable during years of abundance. Jack rabbits are almost never used as food although many are shot for sport or to protect crops.
The black-tailed jack rabbit is a swift runner. [Cottam] and Williams (1943: 263) timed 6 individuals while running under varying conditions. Full speeds for 50 to 300 yards varied from 27 to 38 miles per hour. The maximum speed was attained by two individuals, each for 100 yards.
Embryos found in March numbered 4, 5 and 6.