The animal commonly known as the jackrabbit is actually a hare, a larger relative of the true rabbit, belonging to the genus Lepus. These lagomorphs are widespread across the arid and semi-arid open landscapes of western North America, including deserts, prairies, and shrub-grasslands. Their diet is entirely herbivorous and constantly adapts to the severe seasonal and environmental changes of their habitat. The jackrabbit’s survival hinges on its ability to switch between readily available, moisture-rich plants and hardier, less palatable woody vegetation.
The Preferred Herbaceous Diet
When resources are abundant, such as during the spring and early summer, the jackrabbit focuses on tender, green vegetation. This preferred diet consists mainly of various grasses and forbs, which are broad-leafed flowering plants. They seek out young, succulent shoots of grasses like crested wheatgrass, cheatgrass, and various species of clover and alfalfa. These fresh plants offer the highest concentration of both energy and protein, supporting the animals during their peak breeding season. As the growing season progresses, their diet diversifies to include more forbs, but the focus remains on the rapid consumption of high-quality green matter before it matures and dries out.
Survival Foods and Moisture Sourcing
The jackrabbit’s diet shifts dramatically when the weather turns colder or during periods of drought, transitioning from preferred greens to survival foods. During the fall and winter, or in extremely dry conditions, the primary food source becomes woody browse, dried vegetation, and the bark of shrubs and small trees. Shrubs like sagebrush and mesquite constitute a substantial portion of their intake during these lean times, helping them maintain energy when herbaceous plants are scarce. Obtaining sufficient water is a constant challenge, and the jackrabbit meets this need almost entirely through its diet. Instead of seeking open water sources, they consume water-retaining plants to fulfill their hydration requirements, including moisture-rich succulents and the pads of cacti, such as prickly pear, a food source they can tolerate despite the spines and plant toxins.
Consumption Habits and Agricultural Impacts
Jackrabbits are generally most active and forage for food during the hours around dusk and throughout the night, a pattern known as crepuscular or nocturnal feeding. This behavioral strategy allows them to avoid the heat of the day in their open, arid habitats and provides a measure of security from predators. During the day, they rest in shallow depressions called forms, relying on camouflage for protection.
The animal maximizes nutrient absorption from its fibrous diet through a process called coprophagy, which involves re-ingesting specialized soft fecal pellets. These pellets, called caecotrophes, are produced in the cecum, where microbes break down tough plant cellulose. Eating the caecotrophes allows the jackrabbit to recover protein, B vitamins, and other nutrients synthesized by these microbes.
The jackrabbit’s flexible diet and large appetite often bring them into conflict with human agriculture. They readily consume various cultivated crops, with alfalfa and grain crops like barley being highly sought after. During population spikes, they can cause significant damage to seedling grain, hay, and vegetable fields, though the extent of the damage varies depending on local preference and the availability of their natural forage.