Saturday, July 20, 2013

Devils Tower Prairie Dogs

A black-tailed prairie dog
One of the most-interesting and social rodents of North America can be found at Devils Tower National Monument: the black-tailed prairie dog. French Canadians called them prairie du chien, and later English-speaking explorers used the English translation.
   The prairie dog is actually a member of the squirrel family. They are excellent tunnelers and are aided by their small ears, short tail and powerful legs. Their tan coloring and black tail makes for excellent camouflage against the backdrop of their burrows.
   Their range has been drastically reduced over the last century due to loss of habitat and they are now mainly found on protected areas like Devils Tower National Monument or Badlands National Park in South Dakota.
   Prairie dogs live in densely populated areas called towns. Large towns are divided into wards which are separated by hills, roads, streams or patches of forest. Wards are further divided into coteries. A typical coterie contains one adult male, three or four adult females and several yearlings and juveniles. However, coteries can be as small as two or as large as 39 individuals. If there are two adult males in the same coterie, one is dominant over the other. The residents of each coterie protect their territory from intruders, including prairie dogs from other coteries in the town.
Devils Tower National Monument
   Prairie dogs use the excavated earth from their burrows to make mounds which serve as watch towers and make dikes to divert water from heavy rains. Prairie dogs repair the entrance to their burrows by pounding wet earth into place with their noses. A burrow contains several chambers including a listening post, a toilet and a multi-chambered living area. One chamber of the living area is usually built above the rest to serve as an underground lifeboat by trapping air when the burrow floods.
   Prairie dogs breed from late February until early April. 35 days after conception, four to six blind, hairless pups are born. The mother will actively protect the nest after the pups are born until they are weaned, about six weeks later.
   Prairie dogs are almost wholly vegetarian, although they will eat small insects on occasion. Tall plants are cut down both for food and to increase visibility, leaving only a thin covering of grass and other plants surrounding the burrow. The main source of water for prairie dogs comes from the moisture in the plants and roots they eat. Unlike some other prairie dogs, black-tailed prairie dogs do not truly hibernate and on warm winter days they can be seen actively foraging for vegetation.
   Many carnivores prey on prairie dogs, including coyote, fox, badgers, mink, bobcats, weasels, owls, hawks, eagles, and rattlesnakes.
   Prairie dogs communicate with each other through a variety of methods. When two individuals from the same coterie meet they exchange an identification kiss to show recognition and acceptance. A short, high-pitched warning bark is repeated several times along with a flicking of their tail when danger is sensed. When the town hears a warning bark, they will sit up to see what is causing the alarm. If the warning bark is faster and higher pitched it means a hawk or eagle has been spotted and they will run for the safety of their burrow. After the coast is clear, the prairie dog will throw its forefeet up and point its nose to the sky before coming down on all fours to signal that all is well. This call can also be used to warn prairie dogs not in the coterie that the territory is taken and to stay out.