Learning to Live With Prairie Dogs
A pair of Montana ranchers is showing that cowherds can exist in harmony with these native animals
The sound is unforgettable--like a hundred preschoolers let loose on the prairie with only squeak toys for communication. But the noise doesn't emanate from stuffed animals; it comes from real ones--thousands of black-tailed prairie dogs whose heads bob up and down as they scurry in and out of their burrows, chirping and squeaking warnings and greetings. Their buzzing metropolis stretches across the dusty eastern Montana landscape, as far as the eye can see.
One hundred years ago, a prairie dog town this large would have been commonplace. Back then, the tan-furred, 12-inch-tall burrowing rodents inhabited more than 100 million acres of prairie grasslands from Mexico to Canada. A single town in Texas covered an estimated 25,000 square miles and housed approximately 400 million prairie dogs. But habitat loss, shooting, large-scale poisoning and plague have decimated black-tailed prairie dog populations during the past century and today the animals occupy less than one percent of their historic range.
These facts alone would make this town's size remarkable, but what's more extraordinary is its location: smack dab in the middle of Ned Tranel Jr.'s Twin Buttes ranch near Roundup, Montana. Most livestock ranchers in this part of the country despise prairie dogs, viewing them as pesty competitors for forage. But Tranel sees things differently. "Everything goes together," says the 37-year-old-rancher who, with his sandy brown hair and chiseled face, could easily pass as a brother of football star John Elway. "There's a harmony, and if you're out of sync in one place, you're going to be out of sync everywhere." Together with his father, Ned Sr., Tranel is demonstrating that ranchers and prairie dogs can live in harmony.
Born and raised on an Illinois dairy farm, Tranel Sr., 65, has spent most of his life tending cows. After earning a Ph.D. in psychology, he married and moved his growing family to a 2,500-acre ranch north of Billings. Though he spent much of his time building a successful psychology practice, his family life centered around the ranch. Most of his children moved away, but Ned Jr., the fourth-oldest, returned home after college and went into the ranching business with his father. They started with about 11,000 acres, and in the past 15 years, Twin Buttes has grown to nearly 77,000 acres.
This is no hobby ranch; Twin Buttes turns a profit. The Tranels credit their success to their environmental ethic. The only way to make ranching profitable, they say, is to work with the elements of the ecosystem, instead of against them. They say it's just not economically feasible to spend precious labor and money killing wildlife. They encourage their cattle to live like any other grazing animal on the plains, which means coexisting with prairie dogs and other creatures. The Tranels refuse to trap or kill wildlife on the ranch, even predators such as coyotes.
It's not that the Tranels are partial to coyotes, they just don't see the sense in killing them. "I'm not sure what good a coyote does us, but if you start killing one animal, where do you stop? We don't know what species you can eliminate and still keep the system healthy," says Tranel Sr.
Twin Buttes is prime prairie dog habitat. The land here is vast and open--it curves as if the wind has left ripples on the fluid landscape. Golden grassland stretches from horizon to horizon. The ranch now has about 2,000 acres of prairie dog towns and they're still growing. The towns are punctuated by short mounds marking burrow entrances, which lift toward the sky like miniature volcanoes. These mounds prevent flooding, draw air into the burrows and provide the critters with watchtowers. Prairie dogs spend most daylight hours aboveground, but retreat underground at dark and when predators strike.
The basic prairie dog family unit, called a coterie, consists of one male and several females and their young offspring. Contrary to folklore, prairie dogs don't breed like crazy, says John Hoogland, a biologist at the University of Maryland and author of The Black-Tailed Prairie Dog: Social Life of a Burrowing Mammal. Prairie dogs don't mate until their second year, and only about half of those born each year survive. This high mortality rate is caused in large part by a mysterious spree of infanticide and cannibalism instigated by the female coterie members (excluding the mother). Except for these cannibalistic episodes, prairie dogs are herbivores, and eat mostly native grasses.
It's no accident prairie dogs have been called "nature's lawn mowers." Their towns are as manicured as Florida's best golf courses. Prairie dogs carefully chew down the vegetation around their towns to eliminate predator hiding spots, and they often get a hearty meal in the process. Ranchers view this mowing as bad news; that's grass their cows need. Around 1902, C.H. Merriam of the U.S. Biological Survey declared that prairie dogs diminished grassland productivity by a whopping 50 to 75 percent. These figures have stuck in ranchers' minds ever since, but no one is sure how Merriam came up with the numbers, says U.S. Forest Service biologist Dan Uresk.
So Uresk decided to do the experiments himself. "We asked, ´If you get rid of prairie dogs, how much forage do you gain?' The answer was about four to seven percent," says Uresk. "It does impact the rancher in dollars and cents." But the costs of poisoning prairie dogs (borne largely by the federal government) outweigh the gains made by eliminating the animals. Because the government pays, however, "Ranchers think, ´Why not poison them if it's free?'" he adds.
Tranel Sr. sees plenty of reasons not to poison them, although he and his son give predators a boost by building poles for raptors and digging trenches where foxes can hide. "It's like a zoo around the prairie dog towns. We've got foxes, snakes, hawks, badgers, plovers and burrowing owls." With prairie dogs around, these species flourish. Uresk's research shows that prairie dog towns have roughly twice the number of species as similar areas without the dogs.
The black-tailed prairie dog is what biologists call a keystone species. Lose the keystone, and the whole ecosystem crumbles down with it. Researchers once believed that as many as 208 species depend on prairie dogs, but a recent review of published data by Natasha Kotliar and her colleagues at the U.S. Geological Survey in Colorado revealed that those estimates were probably too high. Kotliar found strong evidence for nine species relying on prairie dogs, including the endangered black-footed ferret, which feeds almost exclusively on the animals; the mountain plover, a bird that requires the disturbed grassland habitat prairie dogs provide; the burrowing owl, which uses prairie dog burrows for homes; and the ferruginous hawk, which preys on prairie dogs. Evidence for other species was not as strong, or data wasn't available, but Kotliar's study nonetheless confirmed the prairie dog's role as a keystone species.
Prairie dogs do more than just serve as prey, they also perform a valuable service for the prairie--they disturb it. In addition to digging up the soil, prairie dogs clip the vegetation around their burrows, enhancing nitrogen uptake by these plants. "Natural disturbances are an important part of maintaining the prairie ecosystem," says Kotliar. "We're learning that if you change the natural disturbance regime, you alter the ecosystem and you may start losing species."
The black-tailed prairie dog's importance to native grasslands, coupled with the dramatic nosedive in the species' numbers, spurred the National Wildlife Federation in 1998 to petition the U.S. Fish and Wildlife Service (FWS) to protect them under the Endangered Species Act. Last February, the FWS ruled that the black-tailed prairie dog was "warranted but precluded" for protection--meaning the animals won't be listed yet, but they will be reevaluated every year. State fish and wildlife agencies, hoping to avoid federal action, have begun to develop their own plans to protect the species.
For many years, human efforts to poison prairie dogs posed the biggest threat to their long-term survival. That threat still looms, but it's now rivaled by another one: plague. "Plague is the largest threat here; others pale by comparison," says Dennis Flath, a biologist with the Montana Department of Fish, Wildlife and Parks. "Plague is an exotic disease, so prairie dogs have no inherent resistance." Without nearby towns to repopulate, plague can turn a colony into a ghost town.
Despite these threats, agricultural groups oppose listing the prairie dog. Many ranchers see efforts to list the species as a threat to their businesses, and others question the motives behind the petition. "I think this whole prairie dog thing is part of the big conspiracy by the National Wildlife Federation to depopulate the West," rancher Jim Darlington of New Castle, Wyoming, told The Washington Post.
Among the threats posed by the species, many ranchers claim, is that cows and horses break their legs in prairie dog holes. But that's nonsense, says researcher Larry Rittenhouse of Colorado State University. "It would be almost impossible for a cow to break its leg on a prairie dog hole," he says. "I study these animals' behavior, and they are extremely adept at placing their feet. In my 50 years around cattle and horses, I don't personally know of a single incident where a horse or a cow has been injured in a prairie dog hole."
Nor do cattle avoid prairie dog towns. Jim Detling, an ecologist at Colorado State University, has studied prairie dog towns in the mixed-grass prairies of South Dakota. His research shows that bison and pronghorn preferentially graze on prairie dog towns, and cattle seem to do the same. The forage on prairie dog towns is highly nutritious, Detling adds. "We've found that there's a significant increase in the protein content of the plants growing on prairie dog towns," he says. Though cattle seem to prefer prairie dog towns in mixed-grass prairies, work by one of Detling's former graduate students, Debra Guenther, shows that in shortgrass prairies cows neither prefer nor avoid prairie dog towns.
This finding echoes what ranch manager Webb Madison has seen at Twin Buttes. "I don't think the cattle mind the prairie dogs. They don't seem to give them much consideration," he says. But most ranchers--including those in Roundup--don't see it that way. Tranel Jr. was filling up his gas tank at a local station recently when he overheard some other patrons talking about "those crazy Tranels and their funny ideas."
But Tranel Jr. says their profits show he and his father are wily, not crazy. At the same time, he acknowledges that their success is reliant, in part, on the ranch's vast size. "If you have 2,000 acres and 600 of them are a prairie dog town, that's a lot different than when you have 12,000 acres. The impact is larger when your pasture is small," says Tranel Jr. The studies showing that prairie dog towns don't harm cattle may not apply when the dog towns start taking up a larger portion of the landscape, says Rittenhouse.
The key to harmony between prairie dog conservation efforts and ranching, says Steve Torbit, an NWF biologist, is to protect large prairie dog towns where livestock grazing can be rotated seasonally. "This gives us the biggest bang for our conservation buck," Torbit says. To this end, the Tranels have teamed up with The Nature Conservancy to purchase and protect the Matador Ranch, a 60,000-acre parcel in northeast Montana that has several extensive prairie dog towns.
While the Tranels intend to run the ranch as a profitable business, conservationists aim to protect the area's native ecosystem and species. Tranel Jr. says the goals go hand in hand. "For me, it's more enjoyable to ranch in a natural, environmental way. Economically it's the only viable method."
Colorado writer Christie Aschwanden visited the Twin Buttes ranch last summer to gather material for this story.
Keystone of the Prairie
Although they are short of stature, prairie dogs cast a long shadow over grasslands in the western United States. The rodents' burrows provide homes to a number of birds and other creatures, and the prairie dogs provide nutrition to raptors and other predators. As a result, the large towns where prairie dogs live have many more species than similar areas without the creatures. A recent study by the U.S. Geological Survey found that the fortunes of the following nine species are closely tied to those of the diminutive rodents:
- Black-footed ferret
- Burrowing owl
- Mountain plover
- Ferruginous hawk
- Golden eagle
- Swift fox
- Horned lark
- Deer mouse
- Grasshopper mouse
NWF Takes Action
Saving Grasslands and Their Denizens
The National Wildlife Federation is working to protect grassland ecosystems and their wildlife throughout the West. Restoring thriving populations of the black-tailed prairie dog is critical to reaching that goal.
In 1998, NWF petitioned to have the black-tailed prairie dog listed as a threatened species under the Endangered Species Act. Last year, the U.S. Fish and Wildlife Service decided that the species warrants such a listing, but resource constraints preclude the service from taking action.
NWF is now helping state and tribal governments in the prairie dog's historic range to craft management plans that will lead to the recovery of the species and restore the health of our nation's prairies.