Members of the genus Lepus are born well-furred and able to move about. Little or no nest is prepared, although the young are kept hidden for 3 to 4 days. Females may produce up to 4 litters per year with 2 to 8 young per litter. Reproductive rates may vary from year to year depending on environmental conditions.

Where food and shelter are available in one place, no major daily movement of hares occurs. When food areas and shelter areas are separated, morning and evening movements may be observed. Daily movements of 1 to 2 miles (1.6 to 3.2 km) each way are common. In dry seasons, 10 mile (16 km) round trips from desert to alfalfa fields have been reported.

Hares consume 1/2 to 1 pound (1.1 to 2.2 kg) of green vegetation each day. Significant damage occurs when hare concentrations are attracted to orchards, gardens, ornamentals, or other agricultural crops. High jackrabbit populations can also damage range vegetation.

Most damage to gardens, landscapes, or agricultural crops occurs in areas adjacent to swamps or rangeland normally used by hares. Damage may be temporary and usually occurs when natural vegetation is dry. Green vegetation may be severely damaged during these dry periods.

Orchards and ornamental trees and shrubs are usually damaged by overbrowsing, girdling, and stripping of bark, especially by snowshoe hares. This type of damage is most common during winter in northern areas.

Rangeland overbrowsing and overgrazing can occur any time jackrabbit numbers are high. Eight jackrabbits are estimated to eat as much as one sheep, and 41 jackrabbits as much as one cow.

Estimates of jackrabbit populations run as high as 400 jackrabbits per square mile (154/km square) extending over several hundred square miles. Range damage can be severe in such situations, especially where vegetation productivity is low.