Utah prairie dog
| Utah prairie dog | ||||||||||||
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Utah prairie dog |
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| Cynomys parvidens | ||||||||||||
| Allen , 1905 |
The Utah prairie dog ( Cynomys parvidens ) is a ground squirrel from the genus of prairie dogs ( Cynomys ), the smallest species of which it is. The animals live exclusively in the southwest of the state of Utah in the United States.
features
Adult Utah prairie dogs reach a total size of 30 to 36 centimeters, the tail is 2.5 to 6 centimeters, the hind feet are 5.5 to 6.5 centimeters, and the ears are 1.2 to 1.6 centimeters long. The Utah Prairie Dog's coat is colored from cinnamon to clay, with various dark brown markings above and below the eyes. The tail is like the white-tailed and Gunnison prairie dogs with a white tip. A hair change takes place twice a year.
The Utah Prairie Dog is most closely related to the White Tailed Prairie Dog. It is believed that these once formed a species and were separated by geographic barriers. The genetic variation in the Utah prairie dogs is only half that of the blacktail prairie dogs , which is believed to be due to a genetic bottleneck .
distribution and habitat
Utah prairie dogs are endemic to the steppes of the western US state of Utah . The prairie dogs that live in the southwestern quarter of Utah are the most westerly species of their genus.
There they currently live in three large areas: in the Awapa Plateau, in the Paunsaugunt Plateau and the area around the Sevier River and in the eastern Iron and Beaver Counties. Due to climatic changes, more westerly areas are no longer inhabited, as these became too dry due to higher temperatures. Geological boundaries such as deserts and mountains prevent them from spreading in east, west and south directions. In northern and central Utah, Uinta ground squirrels competing for habitat form a biological boundary. The habitats of the different species of prairie dogs do not overlap; that of the Utah Prairie Dog is the smallest. In optimal conditions, there can be a population density of up to 74 prairie dogs per hectare .
Population development
Before the colonization of the west by European immigrants, the prairie dogs populated vast areas, primarily within the Great Plains . During this time there was a protocooperation between the prairie dogs and bison . The constantly moving bison rarely left overgrazed meadows and thus allowed large, but stable populations of prairie dogs. With bison extinction and extensive livestock farming, overgrazing created large short-grass habitats that allowed an increase to over 400,000 Utah prairie dogs.
Ranchers began using pesticides to control prairie dogs around 1880, with support from the federal government. At the beginning of the 20th century, programs to control population numbers were started. In the 1920s, the Utah prairie dog population was estimated at 95,000 individuals. Until the 1960s, the population was reduced dramatically, largely due to disease, drought, poisoning and other anthropogenic interventions. In the years 1933, 1950 and 1960 in particular, prairie dogs were fought intensely with poison. Collier and Spillett found only 3,300 Utah Prairie Dogs living in 37 different colonies in their 1972 studies, and they predicted the Utah Prairie Dog to be extinct by 2000.
Since 1975, a census of animals surviving the winter has been carried out every spring. The populations show an upward trend from 1975 to 1989 from 2,975 animals in 1975 to 7,377 animals in 1989 and have remained fairly constant since then. In 2005, 5,381 were counted in 63 colonies. It is estimated that only 40% to 60% of the population are included in this census, as during this time half of the animals are usually under construction. In the summer months the populations triple and fall back in autumn and winter because of the high mortality. Due to the successful protective measures, the Utah Prairie Dog has only been listed in the IUCN Red List since 1996 as "dependent on protective measures". The Utah prairie dogs still make up by far the smallest population of the total of over 2.5 million prairie dog individuals.
Resettlement
From 1972 to 1989 a total of around 14,000 Utah Prairie dogs were relocated from private properties to former distribution areas in public areas with initially little success as farmers suffered an estimated $ 1.5 million annually (1984) damage. In 1980 more than 80 percent lived on private property, in 1989 it was just over 50 percent. The resettlement and population control programs are viewed as a success by the US Fish and Wildlife Service as the population has stabilized on public land and illegal killing and persecution by landowners has decreased.
Way of life
About two-thirds of the adult population is female because of the higher mortality of male individuals. The oestrus , the section in which the female animal is ready to mate, only lasts a few hours on a single day from late March to early April. As a result, only two thirds of the females become pregnant and after a gestation period of 34 to 35 days give birth to one to seven young (average 3.8 to 4.8). The male prairie dogs kill up to 20 percent of the young before they have left the underground for the first time six weeks after their birth. The young animals, less than 50 percent of which reach adulthood, are fully grown by October and reach sexual maturity at the age of twelve months. 20 percent of the female and 10 percent of the male animals reach the age of four years and rarely get older than five years.
Utah prairie dogs live in a community of a few animals consisting of an adult male, several females, and their offspring. While the female offspring remain in the community, the male offspring leave the den after they have reached sexual maturity. The community lives in a fixed territory whose borders are only regularly crossed by the young animals.
construction
Utah Prairie Dogs prefer subsidence, where there is moist pasture even during periods of drought. For a dry construction, the soil should not be damp to a depth of at least one meter. The surrounding vegetation must be low enough for the Utah Prairie Dogs to see the area. The construction is similar to that of the white-tailed prairie dogs in that the mounds (mounds), which consist of the ejection of the burrow, do not represent a design effort as with the black-tailed prairie dogs, but have a random character. Most mounds have only one entrance, which normally leads into the burrow at a 45 ° angle. However - especially in the older buildings - there can be up to five interconnected entrances. The larger mounds have a diameter of up to three meters and can reach a height of 60 centimeters.
food
Utah prairie dogs are predominantly herbivores and prefer alfalfa and grasses. They have also been seen eating the flowering parts of bushes. Dead vegetation and cow dung are also not spurned by the Utah prairie dogs and are even preferred by the young to leaves and trunks of shrubs. As animal food are mainly leafhoppers .
Enemies
Natural enemies include the coyotes , silver badgers , long-tailed weasels , various birds of prey and grassland rattlesnakes . However, these carnivores cannot endanger established colonies. It is more likely that human influences, droughts, disease and competition for living space with the Uinta ground squirrel lead to decreasing populations.
Web links
- Species Profile: Utah prairie dog (Cynomys parvidens) (en) on the US Fish and Wildlife Service website
- Utah Prairie Dog on the IUCN Red List of Endangered Species
credentials
- ↑ a b c d Utah Prairie Dog Recovery Plan (1991) ( PDF )
- ↑ a b Cynomys parvidens ( PDF ; 275 kB) by Pizzimenti and Collier published in Mammalian Species
- ^ IUCN Species Account , June 16, 2007