How long are prairie dogs pregnant

Black-tailed prairie dogs undergo two molts per year, with slightly different pelage coloration in each molt. The general coloration is brownish to brownish-red dorsally, with whitish fur on the ventrum. During the summer, individual hairs are mixed, with some being banded black at the base, with a whitish band, then a cinnamon band, followed by a subterminal buff band, and a black tip , and some colored either solid black or half black.

The latter type of hairs are longer than banded hairs and are interspersed in the coat. In winter, the banded hairs are different, with black at the base, followed by buff, then cinnamon, and possessing a white tip. Females have 8 grayish mammae that are visible only during pregnancy and lactation. Hoogland, Black-tailed prairie dogs are easily distinguished from Mexican prairie dogs because of non-overlapping geographic ranges.

In addition, C. In addition to having mainly non-overlapping ranges, members of Leucocrossuromys all hibernate, have white- to gray-tipped tails, have smaller molars, and possess distinctly different territorial and antipredator vocalizations than do black-tailed prairie dogs. Mating is closely related to social structure in these animals. The typical mating pattern is polygynous, with a single male mating with multiple females in his home coterie.

However, in some cases, more than one male may be resident in a single, large coterie. In these cases, females within the coterie may mate with both resident males. In such cases, the first male to copulate with the female sires more offspring than does the second.

Additionally, there appears to be some communal nursing of young after the time they appear above ground, qualifying the species for status as a cooperative breeder. Hoogland, ; Hoogland, Reproduction occurs once per year, with the exact timing of mating varying with latitude. In Oklahoma, breeding takes place in January; in Colorado breeding takes place in February.

Between late February and March,balck-tailed prairie dogs in South Dakota breed. Finally, those animals residing in the northern portions of the species range breed in late March and early April. Females of this species are typically sexually receptive only one day of the year.

Females failing to conceive after this initial estrus sometimes enter estrus a second time about 13 days after their first estrus. This probably helps to reduce intermale competition for females. Several behaviors are associated with mating both underground and above ground. These include frequent entrance of a breeding male and estrus female into the same burrow; very high frequency of interaction between the male and female; self licking of genitals in both male and female; gathering of nesting materials by males, and transport of those materials into a burrow; and a later than normal nighttime entrance into the burrow by estrus females.

In additon, male black-tailed prairie dogs have a unique vocalization that is associated only with mating behaviors. Gestation ranges in length from 33 to 38 days, with a mean of Litter sizes ate birth range from 1 to 8 young, with a mean litter size at emergence from the burrow of 3 young. Young are altricial, being born blind, naked, and mostly helpless. Neonates measure approximately 70 mm in length, and weigh an average of 15 g. Fur is evident by the age of 3 weeks, and eyes are open by approximately 5 weeks of age.

The age at weaning varies with litter size, as larger litters nurse longer than smaller litters. Lactation lasts from 37 to 51 days, with a mean of The termination of lactation occurs shortly after emergence from the natal burrow, and after emergence but prior to the end of lactation, pups may nurse from females other than their own mother.

Sexual dimorphism in size is already established by the time juveniles emerge from tehir natal burrows. Males weigh an average of g at emergence and females weigh an average of g. By October, males have acheived an average weight of g, and females an average of g.

Females remain in their natal coterie for life, but males disperse as yearlings. This results in minimization of inbreeding. Also, adult males rarely remain within the same coterie for more than two breeding seasons, thus reducing the possibility that they will mate with their female offspring. The age of sexual maturity varies.

Although most black-tailed prairie dogs copulate for the first time as two-year-olds, some reach maturity earlier or later. Males show sexual asymmetry, being less likely than females to breed as yearlings, and more likely than females to dely reproduction until their third year. Female C. Successful reproduction is positively related to female age. Failure to give birth results from both failure of conception, resorption of embryos, and miscarriage of pregnancies.

Cynomys lodovicianus pups are altricial. They require a large investment by parents in order to ensure their survival. Males are not directly involved in caring for young, but help to protect pups within their coteries by defending the coterie against strange males. The bulk of parental care is provided by females, who nurse, groom, and protect their offspring.

Because of the prevalance of infanticide in this species, young are very vulnerable prior to emergence from their natal burrows.

After emergence from the burrow, however, young are less vulnerable. They eat solid foods primarily, although they continue to nurse for about one week. Interestingly, females in the coterie frequently nurse emergent pups other than their own offspring. As is true for most mammals, most black-tailed prairie dogs die young. Females can live to be up to eight years old, whereas males don't tend to live longer than 5 years under natural conditions. Prairie dogs are the most social of the ground- dwelling sciurids.

Prairie dog colonies, or towns, may contain hundreds of individuals living within a very restricted area. The largest colony ever recorded occured in Texas. Within the town there are certain neighborhoods, or coteries. Females typically remain in their natal coterie, whereas males disperse to a nearby coterie. Each coterie is populated by a group of closely related females sister, mothers, aunts and one or two territorial males. When multiple males are found in a single coterie, they are often brothers.

Territories are defended aggressively from neighbors. Within the coterie, all things are shared most of the time. Burrow systems and food supplies are communal property.

The only exception to this is during rearing of young, when females are aggressive toward one another and defend their burrows and nests from other prairie dogs. Territorial defense is usually shared by all members of the coterie.

Male prairie dogs respond strongly to intrusions of other male prairie dogs, but seem oblivious to invading females. Female prairie dogs, by contrast, show the most aggression toward invading females. Praire dogs have long been noted for their highly social behavior. There is often playing, muzzling, mutal grooming, and a great deal of vocal communication.

For instance, when a prairie dog spots a predator, such as a hawk, badger or black-footed ferret, it raises an alarm call, alerting its neighbors.

All of the prairie dogs hearing this cry quickly scuttle into their burrows for protection. The only time there is strife with a coterie is during the breeding season. Females display dominance relationships only when they are pregnant and lactating. During this time, females fight, and when they have the opportunity, they raid the burrows of other females and kill the pups they find there.

It is not surprising that during this time, females aggressivley defend their natal burrow against other females.

Once the young come above ground, however, harmony returns to the coterie. Indeed, young have been observed following the "wrong" mother into a burrow at night. The female nurses the youngster as if it were her own. It is not certain whether mothers can distinguish their young from the young of other mothers once the young have come above ground. Cynomys ludovicianus is diurnal and active throughout the year.

Unlike many other species of prairie dogs, these animals do not hibernate. While they are active obove ground, observers might see them engaging in a variety of behavior, including moving dirt around to enhance burrow entrances, collecting nesting material, and scratching at fleas. As might be expected from the devotion of these animals to enhancing their burrows, the system of tunnels, nesting chambers, and mounds within a cology can be quite complex. They are used for protection from the elements, as well as from predators.

Entrances are usually from 10 to 30 cm in diameter, although tunnels narrow a bit underground. Burrows measure an average of 5 to 10 m in length and 2 to 3 m in depth. However, burrows may be as long as 33 m amd as deep as 5 m. There are three types of entrances to a C.

The most conspicuous type resembles a minature volcano, and has a high mound of dirt molded into a rim crater. Rim craters range in size from 1 to 1. Rounded, unstructured mounds called dome craters may also be present. These are from 2 to 3 m in diameter, but are usually not taller than 0. The mounds of both types of craters allow individuals to see the surrounding territory to scan for predators.

They also help prevent flooding in the burrow, and increase ventilation of the burrow. The burrows associated with both types af craters are apparently used for avoiding predators, spending the night, and rearing offspring.

The final type of burrow entrance has no noticable mound at all. Such entrances to burrows are often found near the edge of the coterie territory. These burrows are apparently used only to escape predators and the heat of the day.

They are not used at night or for rearing offspring. Communication within C. As might be expected from such a highly social species, means of communication are varied.

Black-tailed prairie dogs have 12 distinct calls, including antipredator calls, and the conspicuous "jump-yip", in which an individual stretches to its full height on hind legs, then throws the forefeet into the air as it calls. The jump-yip call of one individual seems to excite other members of the coterie, as well as individuals in adjacent coteries, into producing their own "jump-yip" calls. In addition to vocal communication, C. Sniffing of other individuals occurs, and implies some chemical communication, especially in the context of mating.

Black-tailed prairie dogs eat primarily leaves, stems, and roots of grasses, weeds, and forbs. The animals typically eaten by prairie dogs are grasshoppers, cutworms, bugs, and beetles. Black-tailed prairie dogs do not need to drink water in order to get the moisture they need to survive. They obtain all the moisture they need from their moist, leafy foods. Most prairie dogs forage close to their burrows when possible, moving into distant foraging areas only when forced to do so by local shortages of green shoots.

Cynomys ludovicianus forages selectively from the plants available in its habitat. Diet also varies seasonally. In the summer, black-tailed prairie dogs prefer to feed upon wheatgrass g. Agopyron , buffalo grass g. Bromus , grama g. Bouteloua , rabbitbush g. Chrusothamnus , and scarlet globmallow. In the winter, they eat prickly pear cactus g. Opuntia , thistles g.

Cirsium , and various roots. Black-tailed prairie dogs fall victim to a variety of predatory species. Terrestrial predators include coyotes , badgers , lynx , black-footed ferrets , rattlesnakes , and bullsnakes.

Avian predators include prairie falcons , golden eagles , and a variety of hawks Accipiter and Buteo. The greatest defense that C. Because there are so many prairie dogs in a single colony, colonies attract the notice of predators. But, because there are so many prairie dogs present, all scanning their environment periodically, predators are readily detected by these rodents. When a predator is noticed, individual prairie dogs give alarm calls, warning their relatives that danger is near.

The prairie dogs can then take shelter immediately in one of the many burrows nearby. Black-tailed prairie dogs play a number of vital roles in their ecosystem. In contrast to precocial offspring, altricial babies are generally hairless, are unable to walk, and are entirely helpless. Anywhere between 1 and 7 babies with an average around are born per litter.

The weaning period is a dangerous time for these juveniles, and is when most infanticides will occur. The mother, therefore, is extremely protective of her nursery burrow, and will often be standoffish toward other prairie dogs approaching. She will continue to bring nesting material NM on a semi-regular basis, and toward the end of the weaning period she may include fresh grass in her NM, likely for the juveniles to begin testing it.

During gestation and the nursery preparation phase, female prairie dogs become hostile toward each other, engaging in territorial disputes over potential nursery burrows, and sometimes even contact fighting. The defensiveness also serves as protection against infanticidal females, who make up the majority of juvenile killers. Synchronization among females means offspring emerge at approximately the same time in the summer: late May to early June.

Juveniles are timid when they first emerge, but as they become more aware of their surroundings over a few days, they begin to venture farther from their nursery burrow, interacting with other litters, exploring their surroundings, and watching and learning from yearlings and adults around them. Juveniles are not yet fully weaned upon first emergence but are ready to forage on grass and greens on their own. Occasionally the growing juveniles will continue to nurse, though mothers will spend the majority of their days foraging away from the home burrow; now that their babies are old enough to put up a fight, the threat to them from infanticidal conspecifics is greatly diminished.

This does not mean mothers no longer protect their offspring, however, as they are never too far away and will come home throughout the day to check on their babies. Hostilities among lactating females generally comes to an end when litters begin to emerge, as the risk of infanticide drops considerably now the juveniles are large enough to defend themselves.

Occasionally, though, disagreements still arise between females, especially those who appear to show more protectiveness over their nursery burrow and offspring. These disagreements are usually brief, however. Sometimes a nursery burrow becomes compromised, and the mother may feel it is no longer safe or ideal to keep her offspring there.

Perhaps an infanticidal event has occurred nearby, or a predator has threatened her burrow, or there has been human disturbance.

At any time after birth, and even after juveniles have emerged, a mother may feel the need to transfer her offspring to a new burrow. The first step she takes is usually preparing the new burrow by bringing nesting material into it, either newly collected or grabbed from the compromised nursery.

When she is satisfied, she will begin the transfer. If the babies are very small, they will be carried one-by-one in their mother's mouth; if the babies are too large to carry or otherwise old enough to run, the mother will give them a unique and quiet vocal signal, often accompanied by kisses, and will lead her offspring to follow her to the new burrow - sometimes one-at-a-time and sometimes multiple in a line.

Whether leading or carrying, it may take anywhere from several minutes to half a day for a mother to complete a transfer, as she is often interrupted by the impulse to forage. We don't know if prairie dogs are capable of counting but it does not appear that they count their offspring during transfers. Rather, to assure no one has been left behind, the mother will frequently come back to the compromised burrow to check underground and around the entrance for any offspring that may remain.

She will do this until she is satisfied she has left no one behind. Upon first emergence, because juveniles are not fully weaned they are still supplementing with milk. Emergent juveniles will sometimes nurse from their mothers aboveground, and we will sometimes even see lactating mothers suckling nondescendant juveniles — that is, allowing babies who are not their offspring to nurse from them.

This phenomenon has been observed across many taxa of colonial animals, and is called communal nursing. Utah prairie dog female Backstripe allows her own offspring as well as nondescendant offspring to nurse from her.

Photo by Elaine Miller Bond www.