Prairie dogs considered a pest in many agricultural areas in Wyoming

Riverton – “In the 1900s, there were 700 million acres of western grasslands that contained prairie dogs,” stated UW Extension Educator Mae Smith at Fremont County Farm and Ranch Days on Feb. 11.

Today, there are approximately 2 million acres of prairie dog colonies across the West, with two species living in Wyoming.

Species identification

“The black-tailed prairie dog is the most abundant in Wyoming,” noted Smith.

The black-tailed species is slightly larger than white-tailed prairie dogs and can be identified by the black color at the tip of the tail.

“White-tailed prairie dogs hibernate during the winter, so if we drive out and see any this time of year, they are probably the black-tailed variety,” she added.

Both species have golden-brown fur, fairly short legs and well-developed claws on both front and hind feet.

“They also have sensory whiskers and fairly large eyes,” she said.

Prairie dogs are diurnal, meaning they are awake during the day, and they rely on their eyesight to look out for predators and other threats.

“They are highly social, and they can be seen talking and working together to solve problems,” she commented.

Damaging impact

Each animal can eat up to two pounds of grass and forbs per week, which can impact large tracts of land when a whole colony is present.

“Many people who have problems with prairie dogs are cattle producers. The rodents and cows have a dietary overlap of 64 to 90 percent,” Smith explained.

The rodents’ dirt mounds alone can destroy up to 10 percent of the vegetation in a colonized area, and a population can remove anywhere from 18 to 90 percent of available forage.

“Prairie dog towns can cover up to 1,000 acres or more, and each family, known as a coterie, can occupy nearly an acre,” she said.

A coterie typically contains one male, one to four females and all of their offspring less than two years of age.

“An interesting interaction with these rodents is with the Black-footed ferret,” noted Smith.

Black-footed ferrets are an endangered species that live in prairie dog tunnels and must be taken into consideration when controlling for pests.

“Producers are required to look for Black-footed ferrets in their area before they put out rodenticides,” she added.

Control

Producers should be sure to survey their land before use, but rodenticides have been shown to be effective in prairie dog control.

“Prairie dogs prefer short grass and grazed areas because with taller stubble or more leftover grass, they can’t see as well,” commented Smith.

If producers can leave taller vegetation on their properties, they will have less of a chance of attracting colonies to their land.

“Aluminum phosphide and gas cartridges are also fairly effective, but they can be expensive,” she noted.

Trapping is effective for small populations, and shooting may have limited success.

“They get pretty smart about it, so it’s not a good way to completely eliminate a population, but there are people who come from out-of-state and are willing to pay to hunt prairie dogs on producers’ land,” she explained.

Rodenticides

Rodenticides are probably the most effective control. 

Many rodenticides are anticoagulants, or blood-thinners, that create a vitamin K deficiency in the rodents.

“They tie up all of the vitamin K, which is what helps blood clot,” she said. “It doesn’t kill the animal right away, but it builds up until eventually the animal bleeds out internally.”

Warfarin, a common prescription in humans, was the first approved anticoagulant and remains one of the more popular rodenticides.

“Bromethalin impacts the nervous system, and the animal dies much more quickly,” she added.

Methods that create a vitamin D overdose cause calcium buildup in the blood, zinc phosphide reacts with air and water to create a toxic gas, and strychnine impacts the nervous system and causes paralysis.

Caution

“There are a lot of precautions that producers need to take if they are controlling the rodents themselves,” Smith stated.

Non-target poisoning, for example, is something that producers should be wary of, since pets can get sick from eating poisoned animals or become harmed from ingesting poison directly.

“The secondary risk to mammals and birds varies by active ingredient,” she commented.

She also warned producers to take caution when handling prairie dogs or other rodents.

“We want to avoid close contact as much we can,” she said.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at natasha@wylr.net.