Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate . It is most commonly used to pass through winter months – called overwintering .
148-412: Although traditionally reserved for "deep" hibernators such as rodents , the term has been redefined to include animals such as bears and is now applied based on active metabolic suppression rather than any absolute decline in body temperature. Many experts believe that the processes of daily torpor and hibernation form a continuum and utilise similar mechanisms. The equivalent during the summer months
296-542: A Madison, Wisconsin -area pet swap from an unquarantined Gambian pouched rat imported from Ghana , several prairie dogs in captivity acquired monkeypox , and subsequently a few humans were also infected. This led the Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) to issue a joint order banning the sale, trade, and transport within the United States of prairie dogs (with
444-495: A keystone species , with their mounds often being used by other species. Their mound-building encourages grass development and renewal of topsoil , with rich mineral , and nutrient renewal in the soil, which can be crucial for soil quality and agriculture. They are extremely important in the food chain , being important to the diet of many animals such as the black-footed ferret , swift fox , golden eagle , red tailed hawk , American badger , and coyote . Other species, such as
592-489: A veterinarian under quarantine procedures. On 8 September 2008, the FDA and CDC rescinded the ban, making it once again legal to capture, sell, and transport prairie dogs. Although the federal ban has been lifted, several states still have in place their own ban on prairie dogs. The European Union has not lifted its ban on imports from the U.S. of animals captured in the wild. Major European Prairie Dog Associations, such as
740-414: A burrow and one male defending a territory around the burrow. At high population densities, this system breaks down and males show a hierarchical system of dominance with overlapping ranges. Female offspring remain in the colony while male young disperse. The prairie vole is monogamous and forms a lifelong pair bond. Outside the breeding season, prairie voles live with others in small colonies. A male
888-491: A colony of their own. Rodents use scent marking in many social contexts including inter- and intra-species communication, the marking of trails and the establishment of territories. Their urine provides genetic information about individuals including the species, the sex and individual identity, and metabolic information on dominance, reproductive status and health. Compounds derived from the major histocompatibility complex (MHC) are bound to several urinary proteins. The odor of
1036-408: A common proto-hibernating ancestor of birds and mammals, the ability to hibernate or go through torpor would have been lost in most larger mammals and birds. Hibernation would be less favored in larger animals because as animals increase in size, the surface area to volume ratio decreases, and it takes less energy to keep a high internal body temperature, and thus hibernation becomes unnecessary. There
1184-412: A common space, employees sometimes use the term "prairie dogging" to refer to the action of several people simultaneously looking over the walls of their cubicles in response to a noise or other distraction. This action is thought to resemble the startled response of a group of prairie dogs. The same term is also vulgar slang to refer to one who is on the verge of defecating (often involuntarily), with
1332-592: A competing herbivore. Prairie dogs live mainly at altitudes ranging from 2,000 to 10,000 ft (600 to 3,000 m) above sea level. The areas where they live can get as warm as 38 °C (100 °F) in the summer and as cold as −37 °C (−35 °F) in the winter. As prairie dogs live in areas prone to environmental threats, including hailstorms, blizzards, and floods, as well as drought and prairie fires, burrows provide important protection. Burrows help prairie dogs control their body temperature ( thermoregulation ) as they are 5–10 °C (41–50 °F) during
1480-406: A distinct "chirping", has been likened to laughter , and is interpreted as an expectation of something rewarding. In clinical studies, the chirping is associated with positive emotional feelings, and social bonding occurs with the tickler, resulting in the rats becoming conditioned to seek the tickling. However, as the rats age, the tendency to chirp declines. Like most rat vocalizations, the chirping
1628-708: A dog's bark. The name was in use at least as early as 1774. The 1804 journals of the Lewis and Clark Expedition note that in September 1804, they "discovered a Village of an animal the French Call the Prairie Dog". Its genus, Cynomys , derives from the Greek for "dog mouse" (κυων kuōn , κυνος kunos – dog; μυς mus , μυός muos – mouse). The prairie dog is known by several indigenous names. The name wishtonwish
SECTION 10
#17327838851001776-485: A few are predators. The field vole is a typical herbivorous rodent and feeds on grasses, herbs, root tubers, moss, and other vegetation, and gnaws on bark during the winter. It occasionally eats invertebrates such as insect larvae. The plains pocket gopher eats plant material found underground during tunneling, and also collects grasses, roots, and tubers in its cheek pouches and caches them in underground larder chambers. The Texas pocket gopher avoids emerging onto
1924-476: A few exceptions). The disease was never introduced to any wild populations. The European Union also banned importation of prairie dogs in response. All Cynomys species are classed as a "prohibited new organism" under New Zealand's Hazardous Substances and New Organisms Act 1996 , preventing them from being imported into the country. Prairie dogs are also very susceptible to bubonic plague , and many wild colonies have been wiped out by it. Also, in 2002,
2072-588: A few have become specialized to rely on a diet of animal matter. A functional-morphological study of the rodent tooth system supports the idea that primitive rodents were omnivores rather than herbivores. Studies of the literature show that numerous members of the Sciuromorpha and Myomorpha, and a few members of the Hystricomorpha, have either included animal matter in their diets or been prepared to eat such food when offered it in captivity. Examination of
2220-444: A high-fiber diet; their molars have no roots and grow continuously like their incisors. In many species, the molars are relatively large, intricately structured, and highly cusped or ridged. Rodent molars are well equipped to grind food into small particles. The jaw musculature is strong. The lower jaw is thrust forward while gnawing and is pulled backwards during chewing. Gnawing uses incisors and chewing uses molars, however, due to
2368-515: A large group of prairie dogs in captivity in Texas were found to have contracted tularemia . The prairie dog ban is frequently cited by the CDC as a successful response to the threat of zoonosis . Prairie dogs that were in captivity at the time of the ban in 2003 were allowed to be kept under a grandfather clause , but were not to be bought, traded, or sold, and transport was permitted only to and from
2516-652: A large vacuum device. They can be difficult to breed in captivity, but breed well in zoos. Removing them from the wild was a far more common method of supplying the market demand. They can be difficult pets to care for, requiring regular attention and a very specific diet of grasses and hay. Each year, they go into a period called rut that can last for several months, in which their personalities can drastically change, often becoming defensive or even aggressive. Despite their needs, prairie dogs are very social animals and come to seem as though they treat humans as members of their colony. In mid-2003, due to cross-contamination at
2664-405: A later point. This difference in development is evidence, though inconclusive, that they evolved by slightly different mechanisms and thus at different times. As reptiles are ectothermic, having no system to deal with cold temperatures would be deadly in many environments. Reptilian winter dormancy, or brumation, likely evolved to help reptiles survive colder conditions. Reptiles that are dormant in
2812-539: A means of intra-specific communication during courtship among the Cape mole rat . Footdrumming has been reported to be involved in male-male competition; the dominant male indicates its resource holding potential by drumming, thus minimizing physical contact with potential rivals. Some species of rodent are monogamous, with an adult male and female forming a lasting pair bond . Monogamy can come in two forms; obligate and facultative. In obligate monogamy, both parents care for
2960-504: A means to survive in their shoreline habitat, where water and oxygen levels vary with the tide. Other animals able to survive long periods with very little or no oxygen include goldfish , red-eared sliders , wood frogs , and bar-headed geese . The ability to survive hypoxic or anoxic conditions is not closely related to endotherm hibernation. Some animals can literally survive winter by freezing. For example, some fish , amphibians , and reptiles can naturally freeze and then "wake" up in
3108-523: A modest decline in body temperature (3–5 °C) compared with the much larger decreases (often 32 °C or more) seen in other hibernators. Many researchers thought that their deep sleep was not comparable with true, deep hibernation, but this theory was refuted by research in 2011 on captive black bears and again in 2016 in a study on brown bears . Hibernating bears are able to recycle their proteins and urine, allowing them to stop urinating for months and to avoid muscle atrophy . They stay hydrated with
SECTION 20
#17327838851003256-452: A nursery chamber with other mothers; since most nursing occurs at night, this may be a case of communal nursing. In the case of the latter, others suggest communal nursing occurs only when mothers mistake another female's young for their own. Infanticide is known to occur in prairie dogs. Males that take over a family group will kill the offspring of the previous male. This causes the mother to go into estrus sooner. However, most infanticide
3404-686: A part in social communication between dormice and are used when the individuals are out of sight of each other. House mice use both audible and ultrasonic calls in a variety of contexts. Audible vocalizations can often be heard during agonistic or aggressive encounters, whereas ultrasound is used in sexual communication and also by pups when they have fallen out of the nest. Laboratory rats (which are brown rats, Rattus norvegicus ) emit short, high frequency, ultrasonic vocalizations during purportedly pleasurable experiences such as rough-and-tumble play, when anticipating routine doses of morphine , during mating, and when tickled. The vocalization, described as
3552-481: A periodic internal clock, which is likely triggered by cooler outside temperatures, as shown in the Texas horned lizard ( Phrynosoma cornutum ). One mechanism that reptiles use to survive hibernation, hypercapnic acidosis (the buildup of carbon dioxide in the blood), is also present in mammal hibernation. This is likely an example of convergent evolution . Hypercapnic acidosis evolved as a mechanism to slow metabolism and also interfere with oxygen transport so that oxygen
3700-418: A physiological state wherein the body temperature drops to near ambient temperature, and heart and respiration rates slow drastically. The typical winter season for obligate hibernators is characterized by periods of torpor interrupted by periodic, euthermic arousals, during which body temperatures and heart rates are restored to more typical levels. The cause and purpose of these arousals are still not clear;
3848-458: A predator depresses scent-marking behavior. Rodents are able to recognize close relatives by smell and this allows them to show nepotism (preferential behavior toward their kin) and also avoid inbreeding. This kin recognition is by olfactory cues from urine, feces and glandular secretions. The main assessment may involve the MHC, where the degree of relatedness of two individuals is correlated to
3996-499: A predator warning or defensive action. It is used primarily by fossorial or semi-fossorial rodents. The banner-tailed kangaroo rat produces several complex footdrumming patterns in a number of different contexts, one of which is when it encounters a snake. The footdrumming may alert nearby offspring but most likely conveys that the rat is too alert for a successful attack, thus preventing the snake's predatory pursuit. Several studies have indicated intentional use of ground vibrations as
4144-414: A response to stressors from the environment. A good example of the differences between these two types of hibernation can be seen in prairie dogs . The white-tailed prairie dog is an obligate hibernator, while the closely related black-tailed prairie dog is a facultative hibernator. While hibernation has long been studied in rodents (namely ground squirrels ), no primate or tropical mammal
4292-442: A seasonal diapause, where many of their biological functions end up paired with a seasonal rhythm within the organism. This is a very similar mechanism to the evolution of insect migration, where instead of bodily functions like metabolism getting paired with seasonal indicators, movement patterns would be paired with seasonal indicators. While most animals that go through winter dormancy lower their metabolic rates, some fish, such as
4440-403: A single female monopolizes mating from at least three males. In most rodent species, such as brown rats and house mice, ovulation occurs on a regular cycle while in others, such as voles, it is induced by mating . During copulation, males of some rodent species deposit a mating plug in the female's genital opening, both to prevent sperm leakage and to protect against other males inseminating
4588-412: A single upper and lower pair of ever-growing incisors. Well-known rodents include mice , rats , squirrels , prairie dogs , porcupines , beavers , guinea pigs , and hamsters . However, rabbits , hares , and pikas , which also have incisors that grow continuously (but have two pairs of upper incisors instead of one), were once included with rodents, but are now considered to be in a separate order,
Hibernation - Misplaced Pages Continue
4736-549: A small part of its diet is plant material. It has a chunky body with short legs and tail, but is agile and can easily overpower prey as large as itself. Rodents exhibit a wide range of types of social behavior ranging from the mammalian caste system of the naked mole-rat , the extensive "town" of the colonial prairie dog , through family groups to the independent, solitary life of the edible dormouse . Adult dormice may have overlapping feeding ranges, but they live in individual nests and feed separately, coming together briefly in
4884-472: A territory defends it, and antagonistic behavior occurs between two males of different families to defend their territories. These interactions may happen 20 times per day and last five minutes. When two prairie dogs encounter each other at the edges of their territories, they stare, make bluff charges, flare their tails, chatter their teeth, and sniff each other's perianal scent glands. When fighting, prairie dogs bite, kick, and ram each other. If their competitor
5032-687: A town, called "wards", which are separated by a physical barrier. Family groups exist within these wards. Most prairie dog family groups are made up of one adult breeding male, two or three adult females, and one or two male offspring and one or two female offspring. Females remain in their natal groups for life, thus are the source of stability in the groups. Males leave their natal groups when they mature to find another family group to defend and breed in. Some family groups contain more breeding females than one male can control, so have more than one breeding adult male in them. Among these multiple-male groups, some may contain males that have friendly relationships, but
5180-424: A very descriptive language and have calls for any potential threat. Alarm response behavior varies according to the type of predator announced. If the alarm indicates a hawk diving toward the colony, all the prairie dogs in its flight path dive into their holes, while those outside the flight path stand and watch. If the alarm is for a human, all members of the colony immediately rush inside the burrows. For coyotes,
5328-438: Is aestivation . Hibernation functions to conserve energy when sufficient food is not available. To achieve this energy saving, an endothermic animal decreases its metabolic rate and thereby its body temperature. Hibernation may last days, weeks, or months—depending on the species, ambient temperature, time of year, and the individual's body-condition. Before entering hibernation, animals need to store enough energy to last through
5476-446: Is around their size or smaller, the females participate in fighting. Otherwise, if a competitor is sighted, the females signal for the resident male. Prairie dog copulation occurs in the burrows, which reduces the risk of interruption by a competing male. They are also at less risk of predation. Behaviors that signal that a female is in estrus include underground consorting, self-licking of genitals, dust-bathing, and late entrances into
5624-404: Is at frequencies too high for humans to hear without special equipment, so bat detectors have been used for this purpose. Rodents, like all placental mammals except primates, have just two types of light receptive cones in their retina, a short wavelength "blue-UV" type and a middle wavelength "green" type. They are therefore classified as dichromats ; however, they are visually sensitive into
5772-494: Is at its lowest when the females are pregnant, which is also when the males are depleted from breeding. Despite their name, a prairie dog skull has a condylobasal length of between 5.2-6.4 cm shorter than the skull of a canine or actual dog which is between 11.39–17.96 cm in length. The average lifespan of a prairie dog in the wild is 8 to 10 years. Prairie dogs are chiefly herbivorous, although they occasionally eat insects . They feed primarily on grasses and small seeds. In
5920-445: Is done by close relatives. Lactating females will kill the offspring of a related female both to decrease competition for the female's offspring and for increased foraging area due to a decrease in territorial defense by the victimized mother. Supporters of the theory that prairie dogs are communal breeders state that another reason for this type of infanticide is so that the female can get a possible helper. With their own offspring gone,
6068-460: Is driven by environmental cues, but arousal is driven by physiological cues. Ancient people believed that swallows hibernated, and ornithologist Gilbert White documented anecdotal evidence in his 1789 book The Natural History of Selborne that indicated the belief was still current in his time. It is now understood that the vast majority of bird species typically do not hibernate, instead utilizing shorter periods of torpor . One known exception
Hibernation - Misplaced Pages Continue
6216-402: Is evidence that hibernation evolved separately in marsupials and placental mammals, though it is not settled. That evidence stems from development, where as soon as young marsupials from hibernating species are able to regulate their own heat, they have the capability to hibernate. In contrast, placental mammals that hibernate first develop homeothermy , only developing the ability to hibernate at
6364-641: Is evident in particular subgroups of rodents like kangaroo rats , hamsters, chipmunks and gophers which have two bags that may range from the mouth to the front of the shoulders. True mice and rats do not contain this structure but their cheeks are elastic due to a high degree of musculature and innervation in the region. While the largest species, the capybara , can weigh as much as 66 kg (146 lb), most rodents weigh less than 100 g (3.5 oz). Rodents have wide-ranging morphologies, but typically have squat bodies and short limbs. The fore limbs usually have five digits, including an opposable thumb, while
6512-402: Is mostly driven by the brain stem, which is itself provoked by the cortex. However Legg et al. 1989 find an alternate circuit between the cortex and whiskers through the cerebellar circuits, and Hemelt & Keller 2008 the superior colliculus. Some rodents have cheek pouches , which may be lined with fur. These can be turned inside out for cleaning. In many species, the tongue cannot reach past
6660-915: Is not aggressive towards other males until he has mated, after which time he defends a territory, a female, and a nest against other males. The pair huddles together, grooms one another, and shares nesting and pup-raising responsibilities. Among the most social of rodents are the ground squirrels, which typically form colonies based on female kinship, with males dispersing after weaning and becoming nomadic as adults. Cooperation in ground squirrels varies between species and typically includes making alarm calls, defending territories, sharing food, protecting nesting areas, and preventing infanticide. The black-tailed prairie dog forms large towns that may cover many hectares. The burrows do not interconnect, but are excavated and occupied by territorial family groups known as coteries. A coterie often consists of an adult male, three or four adult females, several nonbreeding yearlings, and
6808-400: Is not understood why this pattern occurs, but in the case of yellow-pine chipmunks , males may have selected larger females due to their greater reproductive success. In some species, such as voles , sexual dimorphism can vary from population to population. In bank voles , females are typically larger than males, but male-bias sexual dimorphism occurs in alpine populations, possibly because of
6956-430: Is not used up and can still reach tissues in low oxygen periods of dormancy. Seasonal diapause, or arthropod winter dormancy, seems to be plastic and quickly evolving, with large genetic variation and strong effects of natural selection present as well as having evolved many times across many clades of arthropods. As such, there is very little phylogenetic conservation in the genetic mechanism for diapause. Particularly
7104-469: Is over, the male is no longer interested in the female sexually, but will prevent other males from mating with her by inserting copulatory plugs . For black-tailed prairie dogs, the resident male of the family group fathers all the offspring. Multiple paternity in litters seems to be more common in Utah and Gunnison's prairie dogs. Mother prairie dogs do most of the care for the young. In addition to nursing
7252-437: Is referred to as diapause. Some researchers and members of the public use the term brumate to describe winter dormancy of reptiles, but the more general term hibernation is believed adequate to refer to any winter dormancy. Many insects, such as the wasp Polistes exclamans and the beetle Bolitotherus , exhibit periods of dormancy which have often been referred to as hibernation, despite their ectothermy. Botanists may use
7400-574: Is selfish or altruistic. Prairie dogs may alert others to the presence of a predator so they can protect themselves, but the calls could be meant to cause confusion and panic in the groups and cause the others to be more conspicuous to the predator than the caller. Studies of black-tailed prairie dogs suggest that alarm-calling is a form of kin selection, as a prairie dog's call alerts both offspring and indirectly related kin, such as cousins, nephews, and nieces. Prairie dogs with kin close by called more often than those that did not have kin nearby. In addition,
7548-538: Is some question as to whether these mothers can distinguish which young are theirs. In the Patagonian mara , young are also placed in communal warrens, but mothers do not permit youngsters other than their own to nurse. Infanticide exists in numerous rodent species and may be practiced by adult conspecifics of either sex. Several reasons have been proposed for this behavior, including nutritional stress, resource competition, avoiding misdirecting parental care and, in
SECTION 50
#17327838851007696-490: Is the common poorwill ( Phalaenoptilus nuttallii ), for which hibernation was first documented by Edmund Jaeger . Because they cannot actively down-regulate their body temperature or metabolic rate, ectothermic animals (including fish, reptiles, and amphibians) cannot engage in obligate or facultative hibernation. They can experience decreased metabolic rates associated with colder environments or low oxygen availability ( hypoxia ) and exhibit dormancy (known as brumation). It
7844-462: Is their susceptibility to bubonic plague . As of July 2016 the U.S. Fish and Wildlife Service plans to distribute an oral vaccine it had developed by unmanned aircraft or drones. Until 2003, primarily black-tailed prairie dogs were collected from the wild for the exotic pet trade in Canada, the United States, Japan, and Europe. They were removed from their burrows each spring, as young pups, with
7992-424: Is thought to have originally evolved in three stages. The first is development of neuroendocrine control over bodily functions, the second is pairing of that to environmental changes—in this case metabolic rates decreasing in response to colder temperatures—and the third is the pairing of these controls with reliable seasonal indicators within the arthropod, like biological timers. From these steps, arthropods developed
8140-406: The Cape ground squirrel , the male's testes can be 20 percent of its head-body length. Several rodent species have flexible mating systems that can vary between monogamy, polygyny and promiscuity. Female rodents play an active role in choosing their mates. Factors that contribute to female preference may include the size, dominance and spatial ability of the male. In the eusocial naked mole rats,
8288-605: The Great Plains of North America, the burrowing activities of prairie dogs play important roles in soil aeration and nutrient redistribution, raising the organic content of the soil and increasing the absorption of water. They maintain these grassland habitats, and some large herbivores such as bison and pronghorn prefer to graze near prairie dog colonies due to the increased nutritional quality of forage. Extirpation of prairie dogs can also contribute to regional and local biodiversity loss , increased seed depredation, and
8436-811: The Lagomorpha . Nonetheless, Rodentia and Lagomorpha are sister groups , sharing a single common ancestor and forming the clade of Glires . Most rodents are small animals with robust bodies, short limbs, and long tails. They use their sharp incisors to gnaw food, excavate burrows, and defend themselves. Most eat seeds or other plant material, but some have more varied diets. They tend to be social animals and many species live in societies with complex ways of communicating with each other. Mating among rodents can vary from monogamy , to polygyny , to promiscuity . Many have litters of underdeveloped, altricial young, while others are precocial (relatively well developed) at birth. The rodent fossil record dates back to
8584-585: The Paleocene on the supercontinent of Laurasia . Rodents greatly diversified in the Eocene , as they spread across continents, sometimes even crossing oceans . Rodents reached both South America and Madagascar from Africa and, until the arrival of Homo sapiens , were the only terrestrial placental mammals to reach and colonize Australia. Rodents have been used as food, for clothing, as pets , and as laboratory animals in research. Some species, in particular,
8732-408: The brown rat , the black rat , and the house mouse , are serious pests , eating and spoiling food stored by humans and spreading diseases. Accidentally introduced species of rodents are often considered to be invasive and have caused the extinction of numerous species, such as island birds, the dodo being an example, previously isolated from land-based predators. The distinguishing feature of
8880-610: The cunner , do not. Instead, they do not actively depress their base metabolic rate, but instead they simply reduce their activity level. Fish that undergo winter dormancy in oxygenated water survive via inactivity paired with the colder temperature, which decreases energy consumption, but not the base metabolic rate that their bodies consume. But for the Antarctic yellowbelly rockcod ( Notothenia coriiceps ) and for fish that undergo winter dormancy in hypoxic conditions, they do suppress their metabolism like other animals that are dormant in
9028-410: The eastern grey squirrel , have a large deep masseter , making them efficient at biting with the incisors. The Myomorpha , such as the brown rat, have enlarged temporalis and masseter muscles, making them able to chew powerfully with their molars. In rodents, masseter muscles insert behind the eyes and contribute to eye boggling that occurs during gnawing where the quick contraction and relaxation of
SECTION 60
#17327838851009176-449: The golden-mantled ground squirrel , mountain plover , and the burrowing owl , also rely on prairie dog burrows for nesting areas. Even grazing species, such as plains bison , pronghorn , and mule deer have shown a proclivity for grazing on the same land used by prairie dogs. Nevertheless, prairie dogs are often identified as pests and exterminated from agricultural properties because they are capable of damaging crops, as they clear
9324-477: The golden-mantled ground squirrel , mountain plover , and the burrowing owl , also rely on prairie dog burrows for nesting areas. Grazing species, such as plains bison , pronghorn , and mule deer , have shown a proclivity for grazing on the same land used by prairie dogs. Prairie dogs have some of the most complex systems of communication and social structures in the animal kingdom . The prairie dog habitat has been affected by direct removal by farmers, and
9472-423: The grasslands of North America . There are five recognized species of prairie dog: black-tailed , white-tailed , Gunnison's , Utah , and Mexican prairie dogs . In Mexico, prairie dogs are found primarily in the northern states, which lie at the southern end of the Great Plains : northeastern Sonora , north and northeastern Chihuahua , northern Coahuila , northern Nuevo León , and northern Tamaulipas . In
9620-409: The metabolic water that is produced in sufficient quantities to satisfy the water needs of the bear. They also do not eat or drink while hibernating, but live off their stored fat. Despite long-term inactivity and lack of food intake, hibernating bears are believed to maintain their bone mass and do not suffer from osteoporosis . They also increase the availability of certain essential amino acids in
9768-785: The order Rodentia ( / r oʊ ˈ d ɛ n ʃ ə / roh- DEN -shə ), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws . About 40% of all mammal species are rodents. They are native to all major land masses except for Antarctica , and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal , fossorial (burrowing), saltatorial /ricochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only
9916-656: The Italian Associazione Italiana Cani della Prateria , remain against import from the United States, due to the high death rate of wild captures. Several zoos in Europe have stable prairie dog colonies that generate enough surplus pups to saturate the EU internal demand, and several associations help owners to give adoption to captive-born animals. Prairie dogs in captivity may live up to 10 years. In companies that use large numbers of cubicles in
10064-621: The MHC genes they have in common. In non-kin communication, where more permanent odor markers are required, as at territorial borders, then non-volatile major urinary proteins (MUPs), which function as pheromone transporters, may also be used. MUPs may also signal individual identity, with each male house mouse ( Mus musculus ) excreting urine containing about a dozen genetically encoded MUPs. House mice deposit urine, which contains pheromones, for territorial marking, individual and group recognition, and social organization. Territorial beavers and red squirrels investigate and become familiar with
10212-558: The QT interval changed for both typical hibernators and the bears from summer to winter. This 1977 study was one of the first evidences used to show that bears are hibernators. In a 2016 study, wildlife veterinarian and associate professor at Inland Norway University of Applied Sciences , Alina L. Evans, researched 14 brown bears over three winters. Their movement, heart rate , heart rate variability , body temperature, physical activity, ambient temperature, and snow depth were measured to identify
10360-602: The United States, they range primarily to the west of the Mississippi River , though they have also been introduced in a few eastern locales. They are also found in the Canadian Prairies . Despite the name, they are not actually canines ; prairie dogs, along with the marmots , chipmunks , and several other basal genera belong to the ground squirrels ( tribe Marmotini ), part of the larger squirrel family ( Sciuridae ). Prairie dogs are considered
10508-403: The air while making a call. A jump-yip from one prairie dog causes others nearby to do the same. Ecologists consider the prairie dog to be a keystone species . They are an important prey species, being the primary diet in prairie species such as the black-footed ferret , swift fox , golden eagle , red tailed hawk , American badger , coyote , and ferruginous hawk . Other species, such as
10656-441: The amount of UV that is reflected decreases with time, which in some circumstances can be disadvantageous; the common kestrel can distinguish between old and fresh rodent trails and has greater success hunting over more recently marked routes. Vibrations can provide cues to conspecifics about specific behaviors being performed, predator warning and avoidance, herd or group maintenance, and courtship. The Middle East blind mole rat
10804-559: The ancestor of birds and mammals onto land introduced them to seasonal pressures that would eventually become hibernation. This is true for all clades of animals that undergo winter dormancy; the more prominent the seasons are, the longer the dormant period tends to be on average. Hibernation of endothermic animals has likely evolved multiple times, at least once in mammals—though it is debated whether or not it evolved more than once in mammals—and at least once in birds. In both cases, hibernation likely evolved simultaneously with endothermy, with
10952-564: The animal to restore its available energy sources or to initiate an immune response. Hibernating Arctic ground squirrels may exhibit abdominal temperatures as low as −2.9 °C (26.8 °F), maintaining sub-zero abdominal temperatures for more than three weeks at a time, although the temperatures at the head and neck remain at 0 °C (32 °F) or above. Facultative hibernators enter hibernation only when either cold-stressed, food-deprived, or both, unlike obligate hibernators, who enter hibernation based on seasonal timing cues rather than as
11100-477: The animal to study key hibernation proteins (HP). Researchers have studied how to induce hibernation in humans. The ability to hibernate would be useful for a number of reasons, such as saving the lives of seriously ill or injured people by temporarily putting them in a state of hibernation until treatment can be given. For space travel, human hibernation is also under consideration, such as for missions to Mars . Anthropologists are also studying whether hibernation
11248-554: The bears' heart rate variability dropped dramatically, indirectly suggesting metabolic suppression is related to their hibernation. Two months before the end of hibernation, the bears' body temperature starts to rise, unrelated to heart rate variability but rather driven by the ambient temperature. The heart rate variability only increases around three weeks before arousal and the bears only leave their den once outside temperatures are at their lower critical temperature. These findings suggest that bears are thermoconforming and bear hibernation
11396-524: The breeding season to mate. The pocket gopher is also a solitary animal outside the breeding season, each individual digging a complex tunnel system and maintaining a territory. Larger rodents tend to live in family units where parents and their offspring live together until the young disperse. Beavers live in extended family units typically with a pair of adults, this year's kits, the previous year's offspring, and sometimes older young. Brown rats usually live in small colonies with up to six females sharing
11544-427: The burrow at night. The licking of genitals may protect against sexually transmitted diseases and genital infections, while dust-bathing may protect against fleas and other parasites. Prairie dogs also have a mating call which consists of up to 25 barks with a 3- to 15-second pause between each one. Females may try to increase their reproduction success by mating with males outside their family groups. When copulation
11692-499: The burrow from flooding and a listening post for predators. When hiding from predators, prairie dogs use less-deep chambers that are usually 1 m (3 ft 3 in) below the surface. Nursery chambers tend to be deeper, being 2 to 3 m (6 ft 7 in to 9 ft 10 in) below the surface. Prairie dogs are highly social animals. They live in large colonies or "towns", and collections of prairie dog families can span hundreds of acres. The prairie dog family groups are
11840-404: The burrows from flooding. The holes also possibly provide ventilation as the air enters through the dome crater and leaves through the rim crater, causing a breeze though the burrow. Prairie dog burrows contain chambers to provide certain functions. They have nursery chambers for their young, chambers for night, and chambers for the winter. They also contain air chambers that may function to protect
11988-443: The caller may be trying to make itself more noticeable to the predator. Predators, though, seem to have difficulty determining which prairie dog is making the call due to its " ventriloquistic " nature. Perhaps the most striking of prairie dog communications is the territorial call or "jump-yip" display of the black-tailed prairie dog. A black-tailed prairie dog stretches the length of its body vertically and throws its forefeet into
12136-713: The case of males, attempting to make the mother sexually receptive. The latter reason is well supported in primates and lions but less so in rodents. Infanticide appears to be widespread in black-tailed prairie dogs, including infanticide from invading males and immigrant females, as well as occasional cannibalism of an individual's own offspring. To protect against infanticide from other adults, female rodents may employ avoidance or direct aggression against potential perpetrators, multiple mating, territoriality or early termination of pregnancy. Feticide can also occur among rodents; in Alpine marmots , dominant females tend to suppress
12284-479: The cranial anatomy of rodents these feeding methods cannot be used at the same time and are considered to be mutually exclusive. Among rodents, the masseter muscle plays a key role in chewing, making up 60% – 80% of the total muscle mass among masticatory muscles and reflects rodents' herbivorous diet. Rodent groups differ in the arrangement of the jaw muscles and associated skull structures, both from other mammals and amongst themselves. The Sciuromorpha , such as
12432-412: The current year's offspring. Individuals within coteries are friendly with each other, but hostile towards outsiders. Perhaps the most extreme examples of colonial behavior in rodents are the eusocial naked mole rat and Damaraland mole rat . The naked mole rat lives completely underground and can form colonies of up to 80 individuals. Only one female and up to three males in the colony reproduce, while
12580-594: The degu less visible to predators. Ultraviolet light is abundant during the day but not at night. There is a large increase in the ratio of ultraviolet to visible light in the morning and evening twilight hours. Many rodents are active during twilight hours (crepuscular activity), and UV-sensitivity would be advantageous at these times. Ultraviolet reflectivity is of dubious value for nocturnal rodents. The urine of many rodents (e.g. voles, degus, mice, rats) strongly reflects UV light and this may be used in communication by leaving visible as well as olfactory markings. However,
12728-455: The drivers of the start and end of hibernation for bears. This study built the first chronology of both ecological and physiological events from before the start to the end of hibernation in the field. This research found that bears would enter their den when snow arrived and ambient temperature dropped to 0 °C. However, physical activity, heart rate, and body temperature started to drop slowly even several weeks before this. Once in their dens,
12876-475: The duration of their dormant period, possibly as long as an entire winter. Larger species become hyperphagic , eating a large amount of food and storing the energy in their bodies in the form of fat deposits. In many small species, food caching replaces eating and becoming fat. Some species of mammals hibernate while gestating young, which are born either while the mother hibernates or shortly afterwards. For example, female black bears go into hibernation during
13024-633: The earliest suggested instance of hibernation being in Thrinaxodon , an ancestor of mammals that lived roughly 252 million years ago. The evolution of endothermy allowed animals to have greater levels of activity and better incubation of embryos, among other benefits for animals in the Permian and Triassic periods. In order to conserve energy, the ancestors of birds and mammals would likely have experienced an early form of torpor or hibernation when they were not using their thermoregulatory abilities during
13172-441: The entrances are simply flat holes in the ground, while at other times, they are surrounded by mounds of soil either left as piles or hard-packed. Some mounds, known as dome craters, can be as high as 20–30 cm (7.9–11.8 in). Other mounds, known as rim craters, can be as high as 1 m (3 ft 3 in). Dome craters and rim craters serve as observation posts used by the animals to watch for predators. They also protect
13320-489: The establishment and spread of invasive shrubs. Burrowing rodents may eat the fruiting bodies of fungi and spread spores through their feces, thereby allowing the fungi to disperse and form symbiotic relationships with the roots of plants (which usually cannot thrive without them). As such, these rodents may play a role in maintaining healthy forests. In many temperate regions, beavers play an essential hydrological role. When building their dams and lodges, beavers alter
13468-632: The fall, they eat broadleaf forbs . In the winter, lactating and pregnant females supplement their diets with snow for extra water. They also will eat roots, seeds, fruit, buds, and grasses of various species. Black-tailed prairie dogs in South Dakota eat western bluegrass, blue grama , buffalo grass , six weeks fescue , and tumblegrass , while Gunnison's prairie dogs eat rabbit brush , tumbleweeds , dandelions , saltbush , and cacti in addition to buffalo grass and blue grama. White-tailed prairie dogs have been observed to kill ground squirrels,
13616-821: The female. Females can remove the plug and may do so either immediately or after several hours. Metabolism of thyroid hormones and iodine in the mediobasal hypothalamus changes in response to photoperiod . Thyroid hormones in turn induce reproductive changes. This is found by Watanabe et al. 2004 and 2007, Barrett et al. 2007, Freeman et al. 2007, and Herwig et al. 2009 in Siberian hamsters , Revel et al. 2006 and Yasuo et al. 2007 in Syrian hamsters , Yasuo et al. 2007 and Ross et al. 2011 in rats, and Ono et al. 2008 in mice. Rodents may be born either altricial (blind, hairless and relatively underdeveloped) or precocial (mostly furred, eyes open and fairly developed) depending on
13764-498: The females that live within the territories are known as "resident" females. In the case of marmots, resident males do not appear to ever lose their territories and always win encounters with invading males. Some species are also known to directly defend their resident females and the ensuing fights can lead to severe wounding. In species with non-defense polygyny, males are not territorial and wander widely in search of females to monopolize. These males establish dominance hierarchies, with
13912-517: The few animal groups that can break open the large capsules of the Brazil nut fruit. Too many seeds are inside to be consumed in one meal, so the agouti carries some off and caches them. This helps dispersal of the seeds as any that the agouti fails to retrieve are distant from the parent tree when they germinate. Other nut-bearing trees tend to bear a glut of fruits in the autumn. These are too numerous to be eaten in one meal and squirrels gather and store
14060-600: The finding that rodents entirely lack the ability to vomit. In many species, the penis contains a bone, the baculum ; the testes can be located either abdominally or at the groin. Sexual dimorphism occurs in many rodent species. In some rodents, males are larger than females, while in others the reverse is true. Male-bias sexual dimorphism is typical for ground squirrels , kangaroo rats, solitary mole rats and pocket gophers ; it likely developed due to sexual selection and greater male–male combat. Female-bias sexual dimorphism exists among chipmunks and jumping mice . It
14208-468: The fore to the hind limbs. The agouti is fleet-footed and antelope -like, being digitigrade and having hoof-like nails. The majority of rodents have tails, which can be of many shapes and sizes. Some tails are prehensile , as in the Eurasian harvest mouse , and the fur on the tails can vary from bushy to completely bald. The tail is sometimes used for communication, as when beavers slap their tails on
14356-444: The high-ranking males having access to the most females. This occurs in species like Belding's ground squirrels and some tree squirrel species. Promiscuity , in which both males and females mate with multiple partners, also occurs in rodents. In species such as the white-footed mouse, females give birth to litters with multiple paternities. Promiscuity leads to increased sperm competition and males tend to have larger testicles. In
14504-690: The hind limbs have three to five digits. The elbow gives the forearms great flexibility. The majority of species are plantigrade , walking on both the palms and soles of their feet, and have claw-like nails. The nails of burrowing species tend to be long and strong, while arboreal rodents have shorter, sharper nails. Rodent species use a wide variety of methods of locomotion including quadrupedal walking, running, burrowing, climbing, bipedal hopping ( kangaroo rats and hopping mice ), swimming and even gliding. Scaly-tailed squirrels and flying squirrels , although not closely related, can both glide from tree to tree using parachute-like membranes that stretch from
14652-447: The hole is poorly insulated, the lemur's body temperature fluctuates widely, passively following the ambient temperature; if well insulated, the body temperature stays fairly constant and the animal undergoes regular spells of arousal. Dausmann found that hypometabolism in hibernating animals is not necessarily coupled with low body temperature. Historically it was unclear whether or not bears truly hibernate, since they experience only
14800-432: The immediate area around their burrows of most vegetation. As a result, prairie dog habitat has been affected by direct removal by farmers, as well as the more obvious encroachment of urban development, which has greatly reduced their populations. The removal of prairie dogs "causes undesirable spread of brush", the costs of which to livestock range may outweigh the benefits of removal. Black-tailed prairie dogs comprise
14948-442: The incisors. Rodents have efficient digestive systems, absorbing nearly 80% of ingested energy. When eating cellulose , the food is softened in the stomach and passed to the cecum , where bacteria reduce it to its carbohydrate elements. The rodent then practices coprophagy , eating its own fecal pellets, so the nutrients can be absorbed by the gut. Rodents therefore often produce a hard and dry fecal pellet. Horn et al. 2013 makes
15096-818: The lack of predators and greater competition between males. One of the most widespread groups of mammals, rodents can be found on every continent except Antarctica. They are the only terrestrial placental mammals to have colonized Australia and New Guinea without human intervention. Humans have also allowed the animals to spread to many remote oceanic islands (e.g., the Polynesian rat ). Rodents have adapted to almost every terrestrial habitat, from cold tundra (where they can live under snow) to hot deserts. Some species such as tree squirrels and New World porcupines are arboreal , while some, such as gophers , tuco-tucos , and mole rats, live almost completely underground, where they build complex burrow systems. Others dwell on
15244-484: The largest remaining community. In spite of human encroachment, prairie dogs have adapted, continuing to dig burrows in open areas of western cities. One common concern, which led to the widespread extermination of prairie dog colonies, was that their digging activities could injure horses by fracturing their limbs. According to writer Fred Durso, Jr., of E Magazine , though, "after years of asking ranchers this question, we have found not one example." Another concern
15392-458: The late 20th century, since it is dissimilar from hibernation seen in rodents. Obligate hibernators are animals that spontaneously, and annually, enter hibernation regardless of ambient temperature and access to food. Obligate hibernators include many species of ground squirrels , other rodents , European hedgehogs and other insectivores , monotremes , and marsupials . These species undergo what has been traditionally called "hibernation":
15540-502: The leaves, buds, and inner bark of growing trees, as well as aquatic plants. They store food for winter use by felling small trees and leafy branches in the autumn and immersing them in their pond, sticking the ends into the mud to anchor them. Here, they can access their food supply underwater even when their pond is frozen over. Although rodents have been regarded traditionally as herbivores, most small rodents opportunistically include insects, worms, fungi, fish, or meat in their diets and
15688-508: The majority contain males that have largely antagonistic relationships. In the former, the males tend to be related, while in the latter, they tend not to be related. Two or three groups of females may be controlled by one male. However, among these female groups, no friendly relationships exist. The typical prairie dog territory takes up 0.05–1.01 hectares (0.12–2.50 acres). Territories have well-established borders that coincide with physical barriers such as rocks and trees. The resident male of
15836-760: The males do not provide direct parental care and stay with one female because they cannot access others due to being spatially dispersed. Prairie voles appear to be an example of this form of monogamy, with males guarding and defending females within their vicinity. In polygynous species, males will try to monopolize and mate with multiple females. As with monogamy, polygyny in rodents can come in two forms; defense and non-defense. Defense polygyny involves males controlling territories that contain resources that attract females. This occurs in ground squirrels like yellow-bellied marmots , California ground squirrels , Columbian ground squirrels and Richardson's ground squirrels . Males with territories are known as "resident" males and
15984-487: The more obvious encroachment of urban development, which has greatly reduced their populations. The removal of prairie dogs "causes undesirable spread of brush", the costs of which to livestock range and soil quality often outweighs the benefits of removal. Other threats include disease . The prairie dog is protected in many areas to maintain local populations and ensure natural ecosystems . Prairie dogs are named for their habitat and warning call, which sounds similar to
16132-613: The most basic units of its society. Members of a family group inhabit the same territory. Family groups of black-tailed and Mexican prairie dogs are called "coteries", while "clans" describes family groups of white-tailed, Gunnison's, and Utah prairie dogs. Although these two family groups are similar, coteries tend to be more closely knit than clans. Members of a family group interact through oral contact or "kissing" and grooming one another. They do not perform these behaviors with prairie dogs from other family groups. A prairie dog town may contain 15–26 family groups, with subgroups within
16280-451: The muscle causes the eyeballs to move up and down. The Hystricomorpha , such as the guinea pig, have larger superficial masseter muscles and smaller deep masseter muscles than rats or squirrels, possibly making them less efficient at biting with the incisors, but their enlarged internal pterygoid muscles may allow them to move the jaw further sideways when chewing. The cheek pouch is a specific morphological feature used for storing food and
16428-399: The muscle, as well as regulate the transcription of a suite of genes that limit muscle wasting. A study by G. Edgar Folk, Jill M. Hunt and Mary A. Folk compared EKG of typical hibernators to three different bear species with respect to season, activity and dormancy, and found that the reduced relaxation (QT) interval of small hibernators was the same for the three bear species. They also found
16576-521: The nature of the precise threat. The urgency of the threat is also conveyed by the acoustic properties of the call. Social rodents have a wider range of vocalizations than do solitary species. Fifteen different call-types have been recognized in adult Kataba mole rats and four in juveniles. Similarly, the common degu , another social, burrowing rodent, exhibits a wide array of communication methods and has an elaborate vocal repertoire comprising fifteen different categories of sound. Ultrasonic calls play
16724-675: The nest a few days after they have opened their eyes and initially keep returning regularly. As they get older and more developed, they visit the nest less often and leave permanently when weaned. In precocial species, the mothers invest little in nest building and some do not build nests at all. The female gives birth standing and the young emerge behind her. Mothers of these species maintain contact with their highly mobile young with maternal contact calls. Though relatively independent and weaned within days, precocial young may continue to nurse and be groomed by their mothers. Rodent litter sizes also vary and females with smaller litters spend more time in
16872-564: The nest than those with larger litters. Mother rodents provide both direct parental care, such as nursing, grooming, retrieving and huddling, and indirect parenting, such as food caching, nest building and protection to their offspring. In many social species, young may be cared for by individuals other than their parents, a practice known as alloparenting or cooperative breeding . This is known to occur in black-tailed prairie dogs and Belding's ground squirrels, where mothers have communal nests and nurse unrelated young along with their own. There
17020-437: The offspring and play an important part in their survival. This occurs in species such as California mice , oldfield mice , Malagasy giant rats and beavers. In these species, males usually mate only with their partners. In addition to increased care for young, obligate monogamy can also be beneficial to the adult male as it decreases the chances of never finding a mate or mating with an infertile female. In facultative monogamy,
17168-518: The paths of streams and rivers and allow for the creation of extensive wetland habitats. One study found that engineering by beavers leads to a 33 percent increase in the number of herbaceous plant species in riparian areas . Another study found that beavers increase wild salmon populations. Meanwhile, some rodents are seen as pests , due to their wide range. Most rodents are herbivorous , feeding exclusively on plant material such as seeds, stems, leaves, flowers, and roots. Some are omnivorous and
17316-428: The prairie dogs move to the entrance of a burrow and stand outside the entrance, observing the coyote, while those prairie dogs that were inside the burrows come out to stand and watch, as well. For domestic dogs, the response is to observe, standing in place where they were when the alarm was sounded, again with the underground prairie dogs emerging to watch. Debate exists over whether the alarm calling of prairie dogs
17464-415: The predator is, how big it is and how fast it is approaching. These have been described as a form of grammar. According to Slobodchikoff, these calls, with their individuality in response to a specific predator, imply that prairie dogs have highly developed cognitive abilities. He also writes that prairie dogs have calls for things that are not predators to them. This is cited as evidence that the animals have
17612-559: The question of why hibernators may return periodically to normal body temperatures has plagued researchers for decades, and while there is still no clear-cut explanation, there are multiple hypotheses on the topic. One favored hypothesis is that hibernators build a " sleep debt " during hibernation, and so must occasionally warm up to sleep. This has been supported by evidence in the Arctic ground squirrel . Other theories postulate that brief periods of high body temperature during hibernation allow
17760-702: The reproduction of subordinates by being antagonistic towards them while they are pregnant. The resulting stress causes the fetuses to abort. Rodents have advanced cognitive abilities. They can quickly learn to avoid poisoned baits, which makes them difficult pests to deal with. Guinea pigs can learn and remember complex pathways to food. Squirrels and kangaroo rats are able to locate caches of food by spatial memory , rather than just by smell. Prairie dog Cynomys gunnisoni Cynomys leucurus Cynomys ludovicianus Cynomys mexicanus Cynomys parvidens Prairie dogs (genus Cynomys ) are herbivorous burrowing ground squirrels native to
17908-414: The rest of the members are smaller and sterile, and function as workers. Some individuals are of intermediate size. They help with the rearing of the young and can take the place of a reproductive if one dies. The Damaraland mole rat is characterized by having a single reproductively active male and female in a colony where the remaining animals are not truly sterile, but become fertile only if they establish
18056-408: The rodents is their pairs of continuously growing, razor-sharp, open-rooted incisors . These incisors have thick layers of enamel on the front and little enamel on the back. Because they do not stop growing, the animal must continue to wear them down so that they do not reach and pierce the skull. As the incisors grind against each other, the softer dentine on the rear of the teeth wears away, leaving
18204-798: The scents of their neighbors and respond less aggressively to intrusions by them than to those made by non-territorial "floaters" or strangers. This is known as the " dear enemy effect ". Many rodent species, particularly those that are diurnal and social, have a wide range of alarm calls that are emitted when they perceive threats. There are both direct and indirect benefits of doing this. A potential predator may stop when it knows it has been detected, or an alarm call can allow conspecifics or related individuals to take evasive action. Several species, for example prairie dogs, have complex anti-predator alarm call systems. These species may have different calls for different predators (e.g. aerial predators or ground-based predators) and each call contains information about
18352-441: The sharp enamel edge shaped like the blade of a chisel . Most species have up to 22 teeth with no canines or anterior premolars . A gap, or diastema , occurs between the incisors and the cheek teeth in most species. This allows rodents to suck in their cheeks or lips to shield their mouth and throat from wood shavings and other inedible material, discarding this waste from the sides of their mouths. Chinchillas and guinea pigs have
18500-428: The short tail, and weigh between 0.5 and 1.5 kilograms (1 and 3 lb). Sexual dimorphism in body mass in the prairie dog varies 105 to 136% between the sexes. Among the species, black-tailed prairie dogs tend to be the least sexually dimorphic, and white-tailed prairie dogs tend to be the most sexually dimorphic. Sexual dimorphism peaks during weaning, when the females lose weight and the males start eating more, and
18648-422: The species. The altricial state is typical for squirrels and mice, while the precocial state usually occurs in species like guinea pigs and porcupines. Females with altricial young typically build elaborate nests before they give birth and maintain them until their offspring are weaned . The female gives birth sitting or lying down and the young emerge in the direction she is facing. The newborns first venture out of
18796-433: The spring. These species have evolved freeze tolerance mechanism such as antifreeze proteins . Hibernation induction trigger (HIT) proteins isolated from mammals have been used in the study of organ recovery rates. One study in 1997 found that delta 2 opioid and hibernation induction trigger (HIT) proteins were not able to increase the recovery rate of heart tissue during ischemia. While unable to increase recovery rates at
18944-652: The stomach contents of the North American white-footed mouse , normally considered to be herbivorous, showed 34% animal matter. More specialized carnivores include the shrewlike rats of the Philippines, which feed on insects and soft-bodied invertebrates, and the rakali or Australian water-rat, which devours aquatic insects, fish, crustaceans, mussels, snails, frogs, birds' eggs, and water birds. The grasshopper mouse from dry regions of North America feeds on insects, scorpions, and other small mice, and only
19092-536: The surface of the ground, but may have a burrow into which they can retreat. Beavers and muskrats are known for being semiaquatic, but the rodent best adapted for aquatic life is probably the earless water rat from New Guinea. Rodents have also thrived in human-created environments such as agricultural and urban areas . Though some species are common pests for humans, rodents also play important ecological roles. Some rodents are considered keystone species and ecosystem engineers in their respective habitats. In
19240-435: The surface to feed by seizing the roots of plants with its jaws and pulling them downwards into its burrow. It also practices coprophagy. The African pouched rat forages on the surface, gathering anything that might be edible into its capacious cheek pouches until its face bulges out sideways. It then returns to its burrow to sort through the material it has gathered and eats the nutritious items. Agouti species are one of
19388-484: The surplus in crevices and hollow trees. In desert regions, seeds are often available only for short periods. The kangaroo rat collects all it can find and stores them in larder chambers in its burrow. A strategy for dealing with seasonal plenty is to eat as much as possible and store the surplus nutrients as fat. Marmots do this, and may be 50% heavier in the autumn than in the spring. They rely on their fat reserves during their long winter hibernation . Beavers feed on
19536-487: The term "seed hibernation" to refer to a form of seed dormancy . There is a variety of definitions for terms that describe hibernation in mammals, and different mammal clades hibernate differently. The following subsections discuss the terms obligate and facultative hibernation. The last two sections point out in particular primates, none of whom were thought to hibernate until recently, and bears, whose winter torpor had been contested as not being "true hibernation" during
19684-799: The time of ischemia, the protein precursors were identified to play a role in the preservation of veterinary organ function. Recent advances in recombinant protein technology make it possible for scientists to manufacture hibernation induction trigger (HIT) proteins in the laboratory without the need for animal euthanasia. Bioengineering of proteins can aid in the protection of vulnerable populations of bears and other mammals that produce valuable proteins. Protein sequencing of HIT proteins, such as α 1-glycoprotein-like 88 kDa hibernation-related protein HRP, contributes to this research pool. A study in 2014 utilizes recombinant technology to construct, express, purify, and isolate animal proteins (HP-20, HP-25, and HP-27) outside of
19832-442: The timing and extent of the seasonal diapause seem particularly variable, currently evolving as a response to climate change . As typical with hibernation, it evolved after the increased influence of seasonality as arthropods colonized terrestrial environments as a mechanism to keep energy costs low, particularly in harsher than normal environments, as well as being a good way to time the active or reproductive periods in arthropods. It
19980-438: The transition from ectothermy to endothermy. This is opposed to the previously dominant hypothesis that hibernation evolved after endothermy in response to the emergence of colder habitats. Body size also had an effect on the evolution of hibernation, as endotherms which grow large enough tend to lose their ability to be selectively heterothermic, with bears being one of very few exceptions. After torpor and hibernation diverged from
20128-469: The ultraviolet (UV) spectrum and therefore can see light that humans can not. The functions of this UV sensitivity are not always clear. In degus , for example, the belly reflects more UV light than the back. Therefore, when a degu stands up on its hind legs, which it does when alarmed, it exposes its belly to other degus and ultraviolet vision may serve a purpose in communicating the alarm. When it stands on all fours, its low UV-reflectance back could help make
20276-506: The victimized mother may help raise the young of other females. The prairie dog is well adapted to predators . Using its dichromatic color vision, it can detect predators from a great distance; it then alerts other prairie dogs of the danger with a special, high-pitched call. Constantine Slobodchikoff and others assert that prairie dogs use a sophisticated system of vocal communication to describe specific predators. According to them, prairie dog calls contain specific information as to what
20424-474: The water surface or house mice rattle their tails to indicate alarm. Some species have vestigial tails or no tails at all. In some species, the tail is capable of regeneration if a part is broken off. Rodents generally have well-developed senses of smell , hearing, and vision. Nocturnal species often have enlarged eyes and some are sensitive to ultraviolet light. Many species have long, sensitive whiskers or vibrissae for touch or "whisking" . Whisker action
20572-545: The winter and 15–25 °C (59–77 °F) in the summer. Prairie dog tunnel systems channel rainwater into the water table , which prevents runoff and erosion , and can also change the composition of the soil in a region by reversing soil compaction that can result from cattle grazing. Prairie dog burrows are 5–10 m (16–33 ft) long and 2–3 m (6.6–9.8 ft) below the ground. The entrance holes are generally 10–30 cm (3.9–11.8 in) in diameter. Prairie dog burrows can have up to six entrances. Sometimes,
20720-557: The winter months in order to give birth to their offspring. The pregnant mothers significantly increase their body mass prior to hibernation, and this increase is further reflected in the weight of the offspring. The fat accumulation enables them to provide a sufficiently warm and nurturing environment for their newborns. During hibernation, they subsequently lose 15–27% of their pre-hibernation weight by using their stored fats for energy. Ectothermic animals also undergo periods of metabolic suppression and dormancy , which in many invertebrates
20868-401: The winter tend to have higher survival rates and slower aging. Reptiles evolved to exploit their ectothermy to deliberately cool their internal body temperatures. As opposed to mammals or birds, which will prepare for their hibernation but not directly cause it through their behavior, reptiles will trigger their own hibernation through their behavior. Reptiles seek out colder temperatures based on
21016-438: The winter. The mechanism for evolution of metabolic suppression in fish is unknown. Most fish that are dormant in the winters save enough energy by being still and so there is not a strong selective pressure to develop a metabolic suppression mechanism like that which is necessary in hypoxic conditions. Rodents This is an accepted version of this page Rodents (from Latin rodere , 'to gnaw') are mammals of
21164-525: The young, the mother also defends the nursery chamber and collects grass for the nest. Males play their part by defending the territories and maintaining the burrows. The young spend their first six weeks below the ground being nursed. They are then weaned and begin to surface from the burrow. By five months, they are fully grown. The subject of cooperative breeding in prairie dogs has been debated among biologists. Some argue prairie dogs will defend and feed young that are not theirs, and young seemingly sleep in
21312-421: Was known to hibernate until the discovery of hibernation in the fat-tailed dwarf lemur of Madagascar, which hibernates in tree holes for seven months of the year. Malagasy winter temperatures sometimes rise to over 30 °C (86 °F), so hibernation is not exclusively an adaptation to low ambient temperatures. The hibernation of this lemur is strongly dependent on the thermal behaviour of its tree hole: If
21460-497: Was once thought that basking sharks settled to the floor of the North Sea and became dormant, but research by David Sims in 2003 dispelled this hypothesis, showing that the sharks traveled long distances throughout the seasons, tracking the areas with the highest quantity of plankton . Epaulette sharks have been documented to be able to survive for three hours without oxygen and at temperatures of up to 26 °C (79 °F) as
21608-413: Was possible in early hominid species. As the ancestors of birds and mammals colonized land, leaving the relatively stable marine environments, more intense terrestrial seasons began playing a larger role in animals' lives. Some marine animals do go through periods of dormancy, but the effect is stronger and more widespread in terrestrial environments. As hibernation is a seasonal response, the movement of
21756-509: Was recorded by Lt. Zebulon Pike while on the Arkansas two years after Lewis and Clark's expedition. In Lakota , the word is pispíza or pìspíza . The black-tailed prairie dog ( Cynomys ludovicianus ) was first described by Lewis and Clark in 1804. Lewis described it in more detail in 1806, calling it the "barking squirrel". Prairie dogs are stout-bodied rodents that, on average, are 30 to 40 cm (12 to 16 in) long, including
21904-412: Was the first mammal for which seismic communication was documented. These fossorial rodents bang their head against the walls of their tunnels. This behavior was initially interpreted as part of their tunnel building behavior, but it was eventually realized that they generate temporally patterned seismic signals for long-distance communication with neighboring mole rats. Footdrumming is used widely as
#99900