Шөл кеміргіштері: Жылқықұйрықтар отбасысы

Family of rodents

Jerboas are hopping desert rodents found throughout North Africa and Asia,

When chased, jerboas can run at up to .

Jerboas look somewhat like miniature kangaroos, and have some external similarities. Both have long hind legs, short forelegs, and long tails. Jerboas move around in a similar manner to kangaroos, which is by hopping, or saltation. However, their anatomy is more attuned towards erratic hopping locomotion, making use of sharp turns and great vertical leaps to confuse and escape predators, rather than for sustained hopping over long periods of time. Researchers have found that, when jerboas execute their vertical leaps, the primary tendons in the hindlimbs only recovered and reused on average 4.4% of energy contributed to the jump; this is lower than many hopping animals. Jerboas have metatarsal bones that are fused into one long bone, called the cannon bone. Their cannon bone is more distinct and defined than in other rodents. The tail of a jerboa can be longer than its head and body, and a white cluster of hair is commonly seen at the end of the tail. Jerboas use their tails to balance when hopping, and as a prop when sitting upright. Jerboa fur is fine, and usually the colour of sand. This colour usually matches the jerboa habitat (an example of cryptic colouration). Some species of the jerboa family have long ears like a rabbit, whilst others have ears that are short like those of a mouse or rat. In addition to the Jerboa's large ears, they also have large feet which are a result of multiple genes overlapping each other in their DNA. Researchers found a gene called the shox2 gene that is expressed in Jerboa feet. This gene has the ability to turn other genes on and off and also has been seen to cause mutant limbs. Jerboas can hop 10–13 cm normally but if threatened by a predator the Jerboa can jump up to 3m. Jerboas are most active at twilight (crepuscular). During the heat of the day, they shelter in burrows. At night, they leave the burrows due to the cooler temperature of their environment. They dig the entrances to their burrow near plant life, especially along field borders. During the rainy season, they make tunnels in mounds or hills to reduce the risk of flooding. In the summer, jerboas occupying holes plug the entrance to keep out hot air and, some researchers speculate, predators. Jerboas are solitary creatures. Once they reach adulthood, they usually have their own burrow and search for food on their own. However, occasional "loose colonies" may form, whereby some species of jerboa dig communal burrows that offer extra warmth when it is cold outside. Jerboas do not drink water but instead get their water intake from the food they eat. Jerboas like desert plants; they are best when they are wet but when dried out the Jerboas will dig the plants up and eat the roots because that part of the plant holds the most water. Jerboas will also try to minimize water loss by feeding at night when it is cooler in the desert.

Many species within the family Dipodidae engage in dust bathing, often a way to use chemical communication. Their keen hearing suggests they may use sounds or vibrations to communicate.

Mating systems of closely related species in the family Dipodidae suggest that they may be polygynous. For some closely related jerboa species, mating usually happens a short time after awaking from winter hibernation. A female breeds twice in the summer, and raises from two to six young. Gestation time is between 25 and 35 days. Little is known about parental investment in long eared jerboas. Like most mammals, females nurse and care for their young at least until they are weaned. Food conditions become abundant typically in the spring and summer. This is also when reproduction rates in the jerboas increase. Jerboas have cells that produce sex hormones known as the gonadotropin releasing hormone (GnRH). These cells fire the most in the months of March through July. These cells quit producing GnRH in the autumn, and the jerboa's mating season ends.