Science, Tech, Math › Animals & Nature Hares and Rabbits Scientific Name: Leporidae Share Flipboard Email Print Hares and Rabbits - Leporidae. Phto © Wouter Marck / Getty Images. Animals & Nature Mammals Amphibians Birds Habitat Profiles Reptiles Wildlife Conservation Insects Marine Life Forestry Dinosaurs Evolution View More By Laura Klappenbach Ecology Expert M.S., Applied Ecology, Indiana University Bloomington B.S., Biology and Chemistry, University of Illinois at Urbana-Champaign Laura Klappenbach, M.S., is a science writer specializing in ecology, biology, and wildlife. our editorial process Laura Klappenbach Updated March 08, 2017 Hares and rabbits (Leporidae) together form a group of lagomorphs that includes about 50 species of hares, jackrabbits, cottontails and rabbits. Hares and rabbits have short bushy tails, long hind legs and long ears. In most of the ecosystems they occupy, hares and rabbits are the prey of numerous species of carnivores and predatory birds. Consequently, hares and rabbits are well-adapted for speed (necessary for outrunning their many predators). The long back legs of hares and rabbits enable them to launch into motion quickly and sustain the fast running speeds for considerable distances. Some species can run as fast as 48 miles per hour. The ears of hares and rabbits are generally quite large and well suited to efficiently capture and locate sounds. This enables them to take notice of potential threats at the first suspicious sound. In hot climates, large ears offers hares and rabbits an additional benefit. Due to their large surface area, the ears of hares and rabbits serve to disperse excess body heat. Indeed, hares that live in more tropical climates have larger ears than do those that live in colder climes (and thus have less need for heat dispersal). Hares and rabbits have eyes that are positioned on either side of their head such that their field of vision includes a complete 360 degree circle around their body. Their eyes are large, enabling them to take in ample light in the dim conditions present during the dawn, dark and dusk hours when they are active. The term "hare" is generally used to refer only to true hares (animals belonging to the genus Lepus). The term "rabbit" is used to refer to all remaining subgroups of the Leporidae. In broad terms, hares tend to be more specialized for rapid and sustained running while rabbits are more adapted for digging burrows and exhibit lower levels of running stamina. Hares and rabbits are herbivores. They feed on a variety of plants including grasses, herbs, leaves, roots, bark and fruits. Since these food sources are difficult to digest, hares and rabbits must eat their feces so that food passes through their digestive tract twice and they can extract every last nutrient possible from their meals. This double digestive process is in fact so vital to hares and rabbits that if they are prevented from eating their feces, they will suffer malnutrition and die. Hares and rabbits have a nearly worldwide distribution that excludes only Antarctica, parts of South America, most islands, parts of Australia, Madagascar, and the West Indies. Humans have introduced hares and rabbits to many habitats they otherwise would not naturally inhabit. Hares and rabbits reproduce sexually. They exhibit high reproductive rates as a response to the high mortality rates they often suffer at the hands of predation, disease and harsh environmental conditions. Their gestation period averages between 30 and 40 days. Females give birth to between 1 and 9 young and in most species, they produce several litters per year. The young wean at about 1 month of age and reach sexual maturity quickly (in some species, for example, they are sexually mature at just 5 months of age). Size and Weight About 1 to 14 pounds and between 10 and 30 inches long. Classification Hares and rabbits are classified within the following taxonomic hierarchy: Animals > Chordates > Vertebrates > Tetrapods > Amniotes > Mammals > Lagomorphs > Hares and Rabbits There are 11 groups of hares and rabbits. These include true hares, cottontail rabbits, red rock hares, and European rabbits as well as several other small groups. Evolution The earliest representative of hares and rabbits is thought to be Hsiuannania, a ground dwelling herbivore that lived during the Paleocene in China. Hsiuannania is know from just a few fragments of teeth and jaw bones but scientists are quite certain that the hares and rabbits originated somewhere in Asia.