 The black @-@ tailed jackrabbit diet is composed of shrubs , small trees , grasses , and forbs . Throughout the course of a year , black @-@ tailed jackrabbits feed on most if not all of the important plant species in a community . Growth stage and moisture content of plants may influence selection more than species . Shrubs generally comprise the bulk of fall and winter diets , while grasses and forbs are used in spring and early summer . This pattern varies with climate : <unk> plants are grazed during <unk> periods while the plants are in <unk> to early reproductive stages , and shrubs are used more in dry seasons . Shrubs are <unk> throughout the year , however . Most of a jackrabbit 's body water is replaced by foraging water @-@ rich vegetation . Jackrabbits require a plant 's water weight to be at least five times its dry weight to meet daily water intake requirements . Therefore , black @-@ tailed jackrabbits switch to <unk> ( deep @-@ rooted ) shrubs when <unk> vegetation is recovering from their foraging . 
