This is an accepted version of this page
105-629: Mus monax Linnaeus, 1758 Arctomys monax (Linnaeus, 1758) The groundhog ( Marmota monax ), also known as the woodchuck , is a rodent of the family Sciuridae , belonging to the group of large ground squirrels known as marmots . A lowland creature of North America, it is found through much of the Eastern United States , across Canada and into Alaska . It was first scientifically described by Carl Linnaeus in 1758. The groundhog plays an important role maintaining healthy soil in woodlands and plains ; as such,
210-414: 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
315-491: 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
420-406: 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
525-485: 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
630-588: 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
735-444: 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
840-449: A lot of woodchucks working over a lot of years to create tunnel systems that would pose any risk to a structure. The burrow is used for safety, retreat in bad weather, hibernating, sleeping, love nest, and nursery. In addition to the nest, there is an excrement chamber. The hibernation or nest chamber is lined with dead leaves and dried grasses. The nest chamber may be about twenty inches to three feet (51–91 cm) below ground surface. It
945-539: 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
1050-686: 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
1155-410: A pound of vegetation daily. In early June, woodchucks' metabolism slows, and while their food intake decreases, their weight increases by as much as 100% as they produce fat deposits to sustain them during hibernation and late winter. Instead of storing food, groundhogs stuff themselves to survive the winter without eating. Thought not to drink water, groundhogs are reported to obtain needed liquids from
SECTION 10
#17327725500121260-458: 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
1365-499: 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
1470-403: 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
1575-412: 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,
1680-549: 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
1785-625: A woodchuck may die from infestation or from bacteria transmitted by vectors. In areas of intensive agriculture and the dairying regions of the state of Wisconsin, particularly in southern areas, the woodchuck had been almost extirpated by 1950. Jackson (1961) suggested that exaggerated reports of damage done by the woodchuck led to excessive culling, substantially reducing its numbers in the state. In some areas woodchucks are important game animals and are killed regularly for sport, food, or fur. In Kentucky, an estimated 267,500 M. monax were taken annually from 1964 to 1971. Woodchucks had protected status in
1890-519: A zookeeper and groundhog trainer at the Staten Island Zoo , has been quoted as saying "They're known for their aggression, so you're starting from a hard place. His natural impulse is to kill 'em all and let God sort 'em out . You have to work to produce the sweet and cuddly." Groundhogs cared for in wildlife rehabilitation that survive but cannot be returned to the wild may remain with their caregivers and become educational ambassadors. In
1995-434: Is about 16 inches (41 cm) wide and 14 inches (36 cm) high. There are typically two burrow openings or holes. One is the main entrance, the other a spy hole. Description of the length of the burrow often includes side galleries. Excluding side galleries, Schoonmaker reports the longest was 24 feet (7.3 m), and the average length of eleven dens was 14 feet (4.3 m). W. H. Fisher investigated nine burrows, finding
2100-404: 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
2205-498: Is common to see one or more nearly motionless individuals standing erect on their hind feet watching for danger. When alarmed, they use a high-pitched whistle to warn the rest of the colony, hence the name "whistle-pig". Groundhogs may squeal when fighting, seriously injured, or caught by a predator. Other vocalizations include low barks and a sound produced by grinding their teeth. David P. Barash wrote that he witnessed only two occasions of upright play-fighting among woodchucks and that
SECTION 20
#17327725500122310-641: 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
2415-401: Is located directly behind the most anterior pair. Incisors are used to bite off tough foods, such as red meat. Cattle (cows, bulls, etc.) have none on top but a total of six on the bottom. In cats , the incisors are small; biting off meat is done with the canines and the carnassials . In elephants , the upper incisors are modified into curved tusks (unlike with narwhals , where it is
2520-402: 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
2625-915: 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
2730-517: Is not only a nuisance, but also a bore. It burrows beneath the soil, and then chuckles to see a mowing machine, man and all, slump into one of these holes and disappear.... The committee concludes that, "a small bounty will prove of incalculable good; at all events, even as an experiment, it is certainly worth trying; therefore your committee would respectfully recommend that the accompanying bill be passed." Groundhogs may be raised in captivity, but their aggressive nature can pose problems. Doug Schwartz,
2835-400: 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
2940-758: Is shorter than that of other Sciuridae—only about one-fourth of body length. The groundhog dwells in lowland habitats, unlike other marmots that live in rocky and mountainous areas. Marmota monax has a wide geographic range. The groundhog prefers open country and the edges of woodland, being rarely found far from a burrow entrance. It can typically be found in small woodlots, low-elevation forests, fields and pastures, and hedgerows. It constructs dens in well-drained soil, and most groundhogs have summer and winter dens. Human activity has increased food access and abundance, allowing M. monax to thrive. W.J. Schoonmaker reports that groundhogs may hide when they see, smell, or hear an observer. Marmot researcher Ken Armitage states that
3045-538: 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
3150-469: Is usually in a wooded or brushy area and is dug below the frost line and remains at a stable temperature well above freezing during the winter months. In most areas, groundhogs hibernate from October to March or April, but in more temperate areas, they may hibernate as little as three months. Groundhogs hibernate longer in northern latitudes than southern latitudes. To survive the winter, they are at their maximum weight shortly before entering hibernation. When
3255-406: 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,
Groundhog - Misplaced Pages Continue
3360-605: 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
3465-811: 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
3570-585: 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,
3675-408: 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
3780-410: 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
3885-465: The first molars , the incisors are also the first permanent teeth to erupt, following the same order as the primary teeth, among themselves. Among other animals, the number varies from species to species. Opossums have 18, whereas armadillos have none. Cats, dogs, foxes, pigs, and horses have twelve. Rodents have four. Rabbits and hares ( lagomorphs ) were once considered rodents, but are distinguished by having six—one small pair, called "peg teeth",
3990-785: 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
4095-621: 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
4200-600: The Spring. Beyond their large size, groundhogs have several successful anti-predator behaviors, usually retreating to the safety of their burrow which most predators will not attempt to enter, but also being ready to defend themselves with their sharp claws and large incisors. They can also scale trees to escape a threat. Both their diet and their habit of burrowing make groundhogs serious nuisance animals around farms and gardens. They will eat many commonly grown vegetables. Extensive burrowing can undermine foundations. Very often,
4305-801: The United States and Canada, the yearly Groundhog Day celebration on February 2 has given the groundhog recognition and popularity. The most popularly known of these groundhogs are Punxsutawney Phil , Wiarton Willie , Shubenacadie Sam , Jimmy the Groundhog, Dunkirk Dave , and Staten Island Chuck kept as part of Groundhog Day festivities in Punxsutawney, Pennsylvania ; Wiarton, Ontario ; Sun Prairie, Wisconsin ; Dunkirk, New York ; and Staten Island respectively. The 1993 comedy film Groundhog Day references several events related to Groundhog Day, and portrays both Punxsutawney Phil himself, and
Groundhog - Misplaced Pages Continue
4410-441: 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
4515-450: The annual Groundhog Day ceremony. Famous Southern groundhogs include General Beauregard Lee , based at Dauset Trails Nature Center outside Atlanta, Georgia . Groundhogs are used in medical research on hepatitis B -induced liver cancer . A percentage of the woodchuck population is infected with the woodchuck hepatitis virus (WHV), which is similar to human hepatitis B virus. Humans cannot contract hepatitis from woodchucks with WHV, but
4620-524: 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
4725-713: 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
4830-479: 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
4935-412: 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
5040-435: The deepest point 49 inches (120 cm) down. The longest, including side galleries, was 47 ft 11.5 in (14.62 m). Numbers of burrows per individual groundhog decrease with urbanization . Bachman mentioned that when the young groundhogs are a few months old, they prepare for separation, digging a number of holes in the area of their early home. Some of these holes were only a few feet deep and never occupied, but
5145-594: 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,
5250-406: The dens of groundhogs provide homes for other animals, including skunks, red foxes, and cottontail rabbits. Foxes and skunks feed upon field mice, grasshoppers, beetles, and other creatures that destroy farm crops. In aiding these animals, the groundhog indirectly helps the farmer. In addition to providing homes for itself and other animals, the groundhog aids in soil improvement by bringing subsoil to
5355-489: 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
SECTION 50
#17327725500125460-821: 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
5565-498: 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
5670-517: 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
5775-600: 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
5880-427: The first two or three years, after which weight plateaus. Groundhogs have four incisors , which grow 1.5 millimetres ( 1 ⁄ 16 in) per week. Constant usage wears them down by about that much each week. Unlike the incisors of many other rodents, the incisors of groundhogs are white to ivory-white. Groundhogs are well-adapted for digging, with powerful, short legs and broad, long claws. The groundhog's tail
5985-468: 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
6090-423: The front teeth present in most mammals . They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whereas armadillos have none. Adult humans normally have eight incisors, two of each type. The types of incisors are: Children with a full set of deciduous teeth (primary teeth) also have eight incisors, named
6195-434: The groundhog enters hibernation, there is a drop in body temperature to as low as 35 degrees Fahrenheit (2 °C), heart rate falls to 4–10 beats per minute and breathing rate falls to one breath every six minutes. During hibernation, they experience periods of torpor and arousal. Hibernating woodchucks lose as much as half their body weight by February. They emerge from hibernation with some remaining body fat to live on until
6300-640: The hibernation patterns of groundhogs may lead to benefits for humans, including lowering of the heart rate in complicated surgical procedures. Groundhog burrows have revealed at least two archaeological sites , the Ufferman Site in the U.S. state of Ohio and Meadowcroft Rockshelter in Pennsylvania . Archaeologists have never excavated the Ufferman Site, but the activities of local groundhogs have revealed numerous artifacts . They favor
6405-444: 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
SECTION 60
#17327725500126510-690: 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
6615-442: 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
6720-505: The juices of food-plants, aided by their sprinkling with rain or dew. Groundhogs are excellent burrowers, using burrows for sleeping, rearing young, and hibernating . Groundhog burrows usually have two to five entrances, providing groundhogs their primary means of escape from predators. The volume of earth removed from groundhog burrows in one study averaged 6 cubic feet (0.17 m) per den. The longest burrow measured 24 feet (7.3 m) plus two short side galleries. Though groundhogs are
6825-818: 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
6930-564: The larger number scatter, to burrow on their own. In the wild, groundhogs can live up to six years with two or three being the average life expectancy. In captivity, groundhogs reportedly live up to 14 years. Human development often leaves vacant space near secondary forests , which are indigenous to groundhogs, which ensures that groundhogs in well-developed areas are nearly free of predators other than humans (through various forms of pest control or roadkills) or mid-to-large sized dogs . Occasionally, woodchucks may suffer from parasitism , and
7035-533: The latter being the third most significant prey species per a statewide study in Pennsylvania . Large predators such as gray wolf and eastern cougar are likely extirpated in the east but still may hunt groundhogs on occasion in Canada . Golden eagles can also prey on adult groundhogs, but seldom occur in the same range or in the same habitats as this marmot. Likewise, great horned owls can reportedly, per Bent (1938), prey upon groundhogs but rarely do so, given
7140-502: 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
7245-603: The loose soil of the esker at the site lies, and their burrow digging has brought many objects to the surface: human and animal bones, pottery, and bits of stone. Woodchuck remains were found in the Indian mounds at Aztalan , Jefferson County, Wisconsin. Robert Frost 's poem "A Drumlin Woodchuck" uses the imagery of a groundhog dug into a small ridge as a metaphor for his emotional reticence . Rodent Rodents (from Latin rodere , 'to gnaw') are mammals of
7350-760: 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
7455-421: The manner of the squirrels, and licks its fur after the manner of a cat. Your committee is too wise, however, to be deceived by this purely superficial observation of better habits. Contemporaneous with the ark, the woodchuck has not made any material progress in social science, and it is now too late to reform the wayward sinner. The average age of the woodchuck is too long to please your committee.... The woodchuck
7560-433: The most solitary of the marmots, several individuals may occupy the same burrow. Burrows can pose a serious threat to agricultural and residential development by damaging farm machinery and even undermining building foundations. In a June 7, 2009, Humane Society of the United States article, "How to Humanely Chuck a Woodchuck Out of Your Yard" by John Griffin, director of Humane Wildlife Services, stated you would have to have
7665-451: 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
7770-521: 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
7875-675: 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
7980-564: 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
8085-448: The numerous burrows gave the impression that groundhogs live in communities. Abandoned groundhog burrows benefit many other species by providing shelter. They are used by cottontail rabbits, raccoons, foxes, river otters, eastern chipmunks, and a wide variety of small mammals, snakes, and birds. Groundhogs are one of the few species that enter into true hibernation , and often build a separate "winter burrow" for this purpose. This burrow
8190-437: 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,
8295-518: 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
8400-531: 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. Incisor Incisors (from Latin incidere , "to cut") are
8505-414: 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
8610-408: 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
8715-406: The same way as in permanent teeth . Young children may have from zero to eight incisors depending on the stage of their tooth eruption and tooth development . Typically, the mandibular central incisors erupt first, followed by the maxillary central incisors, the mandibular lateral incisors and finally the maxillary laterals. The rest of the primary dentition erupts after the incisors. Apart from
8820-798: 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
8925-441: 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
9030-590: The social biology of the groundhog is poorly studied. Despite their heavy-bodied appearance, groundhogs are accomplished swimmers and occasionally climb trees when escaping predators or when they want to survey their surroundings. They prefer to retreat to their burrows when threatened; if the burrow is invaded, the groundhog tenaciously defends itself with its two large incisors and front claws. Groundhogs are generally agonistic and territorial toward conspecifics and may skirmish to establish dominance. Outside their burrow, individuals are alert when not actively feeding. It
9135-638: The species is considered a crucial habitat engineer . The groundhog is an extremely intelligent animal, forming complex social networks and capable of understanding social behavior , forming kinship with its young, understanding and communicating threats through whistling , and working cooperatively to solve tasks such as burrowing . Common names for the groundhog include chuck , wood-shock , groundpig , whistle-pig , whistler , thickwood badger , Canada marmot , monax , moonack , weenusk , red monk , land beaver , and, among French Canadians in eastern Canada , siffleux . The name "thickwood badger"
9240-422: 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
9345-561: The state of Wisconsin until 2017. Woodchuck numbers appear to have decreased in Illinois. Wild predators of adult groundhogs in most of eastern North America include coyotes , badgers , bobcats , and foxes (largely red fox ). Many of these predators are successful stealth stalkers that catch groundhogs by surprise before they can escape to their burrows; badgers likely hunt them by digging them out from their burrows. Coyotes in particular are sizable enough to overpower any groundhog with
9450-652: 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
9555-536: 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
9660-435: 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
9765-547: The surface. The groundhog is also a valuable game animal and is considered a difficult sport when hunted in a fair manner. In some parts of the U.S., they have been eaten. A report in 1883 by the New Hampshire Legislative Woodchuck Committee describes the groundhog's objectionable character: The woodchuck, despite its deformities both of mind and body, possesses some of the amenities of a higher civilization. It cleans its face after
9870-484: 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
9975-465: The temporal differences in their behaviors. Young groundhogs (usually those less than a couple months in age) may also be taken by the American mink , and perhaps other small mustelids , cats , timber rattlesnakes , and hawks . Red-tailed hawks can take groundhogs at least of up to the size of yearling juveniles, and northern goshawks can take them up to perhaps weak emergent-adult groundhogs in
10080-469: 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
10185-1009: The upright posture of play-fighting involves sustained physical contact between individuals that may require a degree of social tolerance virtually unknown in M. monax . Alternatively, upright play-fighting may be a part of the woodchuck's behavioral repertoire that rarely is shown because of physical spacing and/or low social tolerance. Mostly herbivorous , groundhogs eat primarily wild grasses and other vegetation, including berries, bark, leaves, and agricultural crops, when available. In early spring, dandelion and coltsfoot are important groundhog food items. Some additional foods include sheep sorrel , timothy-grass , buttercup , persicaria , agrimony , red and black raspberries, mulberries, buckwheat, plantain, wild lettuce, all varieties of clover, and alfalfa. Groundhogs also occasionally eat small animals, such as grubs , grasshoppers , snails , and even bird eggs and baby birds, but are not as omnivorous as many other Sciuridae . An adult groundhog can eat more than
10290-484: The virus and its effects on the liver make the woodchuck the best available animal for the study of viral hepatitis in humans. The only other animal model for hepatitis B virus studies is the chimpanzee, an endangered species. Woodchucks are also used in biomedical research investigating metabolic function , obesity , energy balance , the endocrine system , reproduction , neurology , cardiovascular disease , cerebrovascular disease , and neoplastic disease . Researching
10395-578: The warmer spring weather produces abundant plant materials for food. Males emerge from hibernation before females. Groundhogs are mostly diurnal and are often active early in the morning or late afternoon. Groundhogs are considered the most solitary of the marmot species . They live in aggregations, and their social organization also varies across populations . Groundhogs do not form stable, long-term pair-bonds, and during mating season male-female interactions are limited to copulation . In Ohio , adult males and females associate with each other throughout
10500-474: 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
10605-1326: The words has led to the popular tongue-twister : The groundhog is by far the largest sciurid in its geographical range, except in British Columbia where its range may abut that of its somewhat larger cousin, the hoary marmot . Adults may measure from 41.8 to 68.5 cm ( 16 + 7 ⁄ 16 to 26 + 15 ⁄ 16 in) in total length, including a tail of 9.5 to 18.7 cm ( 3 + 3 ⁄ 4 to 7 + 3 ⁄ 8 in). Weights of adult groundhogs typically fall between 2 and 6.3 kg (4 lb 7 oz and 13 lb 14 oz). Male groundhogs are slightly larger than females on average and, like all marmots, they are considerably heavier during autumn (when engaged in autumn hyperphagia ) than when they emerge from hibernation in spring. Adult males average year-around weight 3.83 kg (8 lb 7 oz), with spring to fall average weights of 3.1 to 5.07 kg (6 lb 13 oz to 11 lb 3 oz) while females average 3.53 kg (7 lb 13 oz), with spring to fall averages of 3.08 to 4.8 kg (6 lb 13 oz to 10 lb 9 oz). Seasonal weight changes reflect circannual deposition and use of fat. Groundhogs attain progressively higher weights each year for
10710-438: The year and often from year to year. Usually groundhogs breed in their second year, but a small proportion may breed in their first. The breeding season extends from early March to mid- or late April, after hibernation. Woodchucks are polygynous but only alpine and woodchuck marmot females have been shown to mate with multiple males. A mated pair remains in the same den throughout the 31- to 32-day gestation period . As birth of
10815-476: The young approaches in April or May, the male leaves the den. One litter is produced annually. Female woodchucks give birth to one to nine offspring, with most litters ranging between 3 and 5 pups. Groundhog mothers introduce their young to the wild once their fur is grown in and they can see. At this time, if at all, the father groundhog comes back to the family. By the end of August, the family breaks up; or at least,
10920-489: Was given in the Northwest to distinguish the animal from the prairie badger . Monax ( Móonack ) is an Algonquian name of the woodchuck, which means "digger" (cf. Lenape monachgeu ). Young groundhogs may be called chucklings. The etymology of the name woodchuck is unrelated to wood or any sense of chucking . It stems from an Algonquian (possibly Narragansett ) name for the animal, wuchak . The similarity between
11025-412: 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
#11988