28-531: See text Caviomorpha Hystricomorpha (from Greek ὕστριξ, hystrix 'porcupine' and Greek μορφή, morphē 'form') is a term referring to families and orders of rodents which has had many definitions throughout its history. In the broadest sense, it refers to any rodent (except dipodoids ) with a hystricomorphous zygomasseteric system . This includes the Hystricognathi , Ctenodactylidae , Anomaluridae , and Pedetidae . Molecular and morphological results suggest
56-487: A diet consisting of seeds and insects . Some species of jerboa, however, such as Allactaga sibirica , are almost entirely insectivorous . Like other rodents, they have gnawing incisors separated from the grinding cheek teeth by a gap, or diastema . The dental formula for dipodids is: Jerboas and birch mice make their nests in burrows, which, in the case of jerboas, may be complex, with side-chambers for storage of food. In contrast, while jumping mice sometimes co-opt
84-510: 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. The bipedal locomotion of jerboas involves hopping, skipping, and running gaits, associated with rapid and frequent, difficult-to-predict changes in speed and direction, facilitating predator evasion relative to quadrupedal locomotion. This may explain why evolution of bipedal locomotion
112-452: A single large family, Dipodidae , which contained jerboas , jumping mice , and birch mice as subfamilies. However, phylogenetic evidence found all three to be distinct families from one another, and thus they were split into three different families within Dipodoidea. Dipodoids are small to medium-sized rodents, ranging from 4 to 26 cm (1.6 to 10.2 in) in body length, excluding
140-543: A well-documented fossil record dating back to the Eocene . These fossil species are definitively known: Primisminthus from the middle Eocene of China could be the oldest member of the group, while Banyuesminthus , also from the middle Eocene of China, could represent a sister group to the rest of the Dipodoidea. Jerboa Jerboas ( / dʒ ɜːr ˈ b oʊ ə / ) are hopping desert rodents found throughout North Africa and Asia, and are members of
168-561: Is actively used throughout the summer and the young are raised there. Jerboas hibernate during the winter and use the permanent winter burrow for this. Temporary burrows are shorter in length than permanent burrows. Just like other animals that hibernate, these creatures are heavier pre-hibernation specifically in ungrazed sites (Shuai). Also, more food availability during pre-hibernation contributes to larger jerboa body mass in ungrazed regions, and entices more jerboas to migrate to ungrazed areas during post-hibernation. Grazing negatively impacts
196-419: Is always longer than the full body. Jerboa dental records reveal a slow increase in crown heights and that corresponds to a more open and dryer ecosystem. 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
224-492: Is cold outside. Most jerboas rely on plant material as the main component of their diet, but they cannot eat hard seeds. Some species opportunistically eat other jerboas and other animals they come across. Unlike gerbils , jerboas are not known to store their food. Some species of Jerboa are known to have a diet that consists of insects, plants, and sometimes seeds. They use their two front legs to gather food. Jerboas do not drink water but instead get their water intake from
252-461: Is favored in desert-dwelling rodents that forage in open habitats. 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
280-498: 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
308-566: Is still controversial, and new scientific discoveries on this subject are published regularly. The following list of families is based on the taxonomy of Marivaux et al. 2002 and Marivaux, Vianey-Liaud & Jaeger 2004 , who subjected a number of early fossil rodents to parsimony analysis and recovered support for the Hystricomorpha or Entodacrya hypothesis. Their results rendered the suborder Sciuravida as defined by McKenna & Bell 1997 to be polyphyletic and invalid. The symbol "†"
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#1732852255428336-491: Is used to indicate extinct groups. [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] [REDACTED] Dipodoidea Dipodidae Sminthidae Zapodidae Dipodoidea is a superfamily of rodents , also known as dipodoids , found across the Northern Hemisphere . This superfamily includes over 50 species among
364-436: 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. In most cases, burrows are constructed with an emergency exit that ends just below the surface or opens at the surface but is not strongly obstructed. This allows the jerboa to quickly escape predators. Since Jerboas dig in
392-561: The tail . They are all adapted for jumping, although to varying degrees. The jerboas have very long hind legs which, in most species, include cannon bones . They move either by jumping, or by walking on their hind legs. The jumping mice have long feet, but lack the extreme adaptations of the jerboas, so that they move by crawling or making short hops, rather than long leaps. Both jerboas and jumping mice have long tails to aid their balance. Birch mice have shorter tails and feet, but they, too, move by jumping. Most dipodoids are omnivorous , with
420-406: The 16 genera in 3 families. They include the jerboas (family Dipodidae ), jumping mice (family Zapodidae ), and birch mice (family Sminthidae ). Different species are found in grassland , deserts , and forests . They are all capable of saltation (jumping while in a bipedal stance), a feature that is most highly evolved in the desert-dwelling jerboas. Formerly, Dipodoidea contained only
448-640: The Eocene, a continent which previously had metatherians , xenarthrans , and meridiungulates as the only resident nonflying mammals. They apparently arrived by rafting across the Atlantic from Africa . The same type of migration may have occurred with primates , which also appeared in South America in the Eocene when it was an isolated continent, long before the Great American Interchange . All of this
476-793: The Jerboa pre- and post-hibernation population, but not the survival rate. Jerboas create burrows to function as protection against predators and severe weather conditions. They will naturally respond to winter conditions such as cold temperatures and food deprivation by digging a winter burrow to hibernate in. Winter burrows are most often longer, deeper and have more entrance holes than summer burrows. Additionally, they use these burrows as nesting areas to raise their young. They can also function as feeding sites. 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
504-446: The burrows of other species, they do not dig their own, and generally nest in thick vegetation. Most species hibernate for at least half the year, surviving on fat that they build up in the weeks prior to going to sleep. Dipodoids give birth to litters of between two and seven young after a gestation period of between 17 and 42 days. They breed once or twice a year, depending on the species. Superfamily Dipodoidea Dipodoidea has
532-484: The cannon bone. Their cannon bone is more distinct and defined than in other rodents. This acts as leverage to allow them to reach higher heights while jumping, while also supporting the legs. Their back legs are often up to four times as long as the front legs. This further allows them to sling-shot themselves into the air. Jerboas that live in sandy desert environments develop hairs on the bottom of their feet that allow for better traction and grip so that they don't slip in
560-413: 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
588-447: The family Dipodidae . They tend to live in hot deserts. When chased, jerboas can run at up to 24 km/h (15 mph). Some species are preyed on by little owls ( Athene noctua ) in central Asia. Most species of jerboas have excellent hearing that they use to avoid becoming the prey of nocturnal predators. The typical lifespan of a jerboa is around 2–3 years. Jerboas, as previously defined, were thought to be paraphyletic , with
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#1732852255428616-491: 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
644-590: 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
672-562: The inclusion of the Anomaluridae and Pedetidae in Hystricomorpha may be suspect. Based on Carleton & Musser 2005 , these two families are discussed here as representing a distinct suborder Anomaluromorpha . The modern definition of Hystricomorpha, also known as Entodacrya or Ctenohystrica , is a taxonomic hypothesis uniting the gundis with the hystricognath rodents . Considerable morphological and strong molecular support exists for this relationship. If true, this hypothesis renders
700-479: The jumping mice ( Zapodidae ) and birch mice ( Sminthidae ) also being classified in the family Dipodidae. However, phylogenetic analysis split all three as distinct families, leaving just the jerboas in Dipodidae and revealing them to be a monophyletic group. This animal has a body length (including the head) of between 4 and 26 cm (1.6 to 10 in.), with an additional 7 – 30 cm (2.75 to 12 in.) of tail, which
728-450: The sand, they have adapted to that environment by developing skin folds and hair that protects their ears and nose from getting sand inside them. Related jerboas often create four types of burrows. A temporary, summer day burrow is used for cover while hunting during the daylight. They have a second, temporary burrow used for hunting at night. They also have two permanent burrows: one for summer and one for winter. The permanent summer burrow
756-403: The sand. Like other bipedal animals, their foramen magnum —the hole at the base of the skull—is forward-shifted, which enhances two-legged locomotion. 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
784-468: The traditional view of Sciurognathi invalid, as it becomes a paraphyletic group. The hystricomorph rodents, or at least members of Caviomorpha , are sometimes not regarded as rodents. Most molecular and genetic research, however, confirms the monophyly of rodents. Support for rodent polyphyly appears to be a product of long branch attraction . Hystricomorph rodents appeared in South America in
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