By Herm Hoops
When you drive to the river put in it is likely that you’ll see prairie dogs racing in front of the van and running between the tires! Most of the time their gamble with fate works, sometimes it doesn’t, supplying easy pickings for ravens, birds of prey and other animals. Prairie dogs occur only in North America. The white-tailed prairie dog is one of three prairie dog species found in Utah, occurring in the northeastern part of the state. The species is also found in parts of Colorado, Wyoming, and Montana. They are rodents within the squirrel family and include five species: white-tailed prairie dog (Cynomys leucurus), black-tailed prairie dog (Cynomys ludovicianus), Gunnison prairie dog (Cynomys gunnisoni), Utah prairie dog (Cynomys parvidens), and Mexican prairie dog (Cynomys mexicanus). All five species of prairie dogs live in colonies and all of which may be considered rare.
The U.S. Bureau of Land Management that controls an estimated 55 percent of white-tailed prairie dog habitat, and the U.S. Fish and Wildlife Service have been reticent to list them in the Threatened or Endangered Species listing. The agencies determined that the potential impacts to the white-tailed prairie dog, including oil and gas exploration, development of oil, tar sands, and other minerals, urbanization, agricultural land conversion, grazing, wildland fire occurrence, climate change, recreational and pest control, shooting, the plague, poisoning, and lack of regulatory mechanisms had little effect on the population!
After 200 years of shooting, poisoning, conversion of habitat, and more recently the plague, prairie dog numbers are a fraction of what they once were. The prairie dog has a pronounced impact on its ecosystem (Kotliar et al. 2006). Prairie dogs increase habitat diversity and contribute to grassland ecosystem processes. They clip the vegetation and maintain open habitats preferred by some animals like the horned lark and mountain plover. Many species, such as American badgers, prairie rattlesnakes, swift foxes and coyotes, hawks and birds of prey and the federally endangered black-footed ferret, prey on prairie dogs or use their burrows for shelter.
Prairie dogs tend to be celebrated for their larger ecological virtues. In the grasslands across the central and western United States, their intricate underground colonies, called prairie dog towns, create shelter for jackrabbits, toads, burrowing owls and rattlesnakes. The bare patches of ground created by their grazing and burrowing attract certain insects that feed a variety of birds. Those little pests, it turns out, are carrying a heavy burden on their uncharismatic backs – an entire ecosystem. The loss of prairie dog habitat has hurt the burrowing owl. Once common across the West, the owl has been considered a species of special concern by the National Audubon Society for over a decade. The owl doesn’t eat many prairie dogs, but it uses the mounds as a sort of lookout tower to spot insects, mice, snakes and lizards. While the
parents are peering around in search of prey, the owlets are sheltered in the nearby scrub brush. The plover prefers to nest in short-grass areas where sagebrush is present, a unique aspect of prairie dog towns. The cropped vegetation of a dog town appeals to the mountain plover, which is endangered in Canada and a species of special concern in Montana. The Fish and Wildlife Service was going to list it as endangered in 1995, but a congressional moratorium on new listings stopped them. The once plentiful swift fox has almost followed the black-footed ferret toward extinction. Only some small pockets survive in South Dakota in prairie dog country.
White-tailed prairie dogs inhabit the western half of Wyoming, western Colorado, the eastern portion of Utah, and a small portion of southern Montana. The largest remaining complexes or groups, occupying more than 5,000 acres each, are primarily found in Wyoming. White-tailed prairie dogs are generally found at altitudes around 5,000 feet in desert grasslands and shrub grasslands. These rodents do not gather in large towns but maintain more scattered burrows. Conversely, the black-tailed prairie dogs are found at altitudes below 6,000 feet in grasslands associated with the Great Plains and are not tolerant of shrubs within their colony. They live in massive, sometimes over 5,000 acres, towns. Prairie dogs have small ears, relatively large black eyes, a short white-tipped tail, and muscular legs. It is a small, stout rodent, about 13 to 15 inches long and weighing one to three pounds. They have a blackish brown cheek patch above and below each eye, and a tan-brown pelt. The so-called prairie dog was named for its barking call.
In contrast with popular perceptions of prairie dogs as fast-multiplying rodents, these animals actually mate just once a year, in early winter. Females go into estrus for a single hour. They then have litters of three to eight pups, usually only half of which survive their first year. They live in tight-knit family groups called coteries. The average coterie tends to have one or two breeding males, several breeding females, and the females’ new pups. Males tend to jump from coterie to coterie—but the females stick together for life.
The towns become argumentative in the spring, when the new litters are born and the yearlings from the last year’s litters attempt to take over. Those who lose, whether young or old, hit the road, following any beaten trail available until they come to a grazed area where they can attempt to create a new town. As important as a description of the prairie dog, is that of its colony site. Colony sites may extend for miles and contain hundreds of mounds that surround the burrow entrances. Prairie dogs live in extensive underground burrows, marked by many mounds of packed earth at their surface entrances. Burrows have defined nurseries, sleeping quarters, and even toilets. They also feature listening posts near exits, so animals can safely keep tabs on the movements of predators outside. Prairie dogs spend a lot of time building and rebuilding these dwellings. Family groups cooperate to share food, chase off other prairie dogs, and groom one another. These group members even greet one another with a prairie dog kiss or nuzzle. Young pups are very playful and can often been seen romping near their burrows.
Black-tailed prairie dogs eat or clip grasses and other plants that grow taller than about 12 inches, so vegetation at colony sites is relatively short, prefer to create their homes in overgrazed areas so the low vegetation can provide protection from predators. White-tailed prairie dogs live in more dispersed colonies with more vegetation. They do not need to drink, because they get all of the water they need from the plants they normally eat (Metabolic water).
White-tailed prairie dogs have a looser social structure and occur at a lower density than black-tailed prairie dogs. They colonize in irregular patterns across the landscape. do not gather in large towns but maintain more scattered burrows. They are fast, skilled fighters armed with sharp claws and powerful teeth. It takes a while for black-footed ferrets to learn how to catch them. Prairie dogs fight back. In addition to providing food and shelter to associated species, prairie dog burrows actually enrich the soil and improve vegetation quality because water concentration is able to flow underground. Prairie dogs. All species hunker down in winter and burn the reserves of fat they have stored during more plentiful seasons. White-tails may hibernate for up to six months on their mountain plains, while their black-tailed
cousins sometimes emerge to feed on especially warm days.
The prairie dogs rebounded momentarily when the homesteaders arrived; cattle and roads provided the trail-making service the bison had once provided. But the homesteaders and ranchers didn’t understand that prairie dogs were giving as well as receiving by actually helping the range. The first hint of this had come from early naturalists, who noted that bison grazed off the sparse vegetation in prairie dog towns before moving on to what looked like better forage outside the towns. Before the near elimination of the bison, the large ungulates migrated and grazed areas heavily providing new habitat for prairie dogs to expand to. The bison used the barren areas created by the prairie dogs for wallowing. Dr. Craig Knowles, a biologist in Montana, who has studied the prairie dogs for the U.S. Forest Service and Fish and Wildlife Service, discovered what the bison had known: “Even though prairie dog towns appear to be desolate, they are full of plant life. The animal’s digging activity disturbs the soil, (and) weedy plants take over, much like in a cultivated field. When closely cropped, these plants become higher in protein and nitrogen content and are sought out by cattle, bison, antelope and elk.”
Knowles says that “all the scientific information shows prairie dogs don’t compete during the summertime with cattle. In winter, though, when the plants are dormant, cattle will not graze in prairie dog towns.” Knowles says it takes about 380 adult prairie dogs to consume as much vegetation as one cow and calf. Their vocabulary is more advanced than any other animal language that’s been decoded They communicate with loud cries. A warning cry, for example, will send a town’s denizens hustling to their holes at the approach of a badger, coyote, or other predator. A second, “all-clear” call alerts the community when the danger has passed. To a human ear, prairie dogs’ squeaky calls sound simple and repetitive. But recent research has found that those calls can convey incredibly descriptive details. Prairie dogs can alert one another, for example, that there’s not just a human approaching their burrows, but a tall human wearing the color blue.
Dr. Craig Knowles, Montana State University and Con Slobodchikoff, professor of biology at Northern Arizona University, have been analyzing the sounds of prairie dogs for more than 30 years at separate locations. Not long after they started, they learned that prairie dogs had distinct alarm calls for different predators. What they discovered in the following decades was extraordinary: Beyond identifying the type of predator, prairie-dog calls also specified its size, shape, color and speed. The animals could even combine the structural elements of their calls in novel ways to describe something they had never seen before. Prairie-dog alarm calls are the vocal equivalent of wartime telegrams: concise, abrupt, stripped to essentials. Their communication is so complex, Slobodchikoff says, so expressive and rich in information, that it constitutes nothing less than language.
It did not take long for Slobodchikoff to master the basic vocabulary of native prairie dogs. On a typical research day, Slobodchikoff and graduate students visited one prairie-dog colony for observation. They usually arrived in the predawn hours and climbed into an observation tower before the creatures emerged from their slumber. By waiting, watching and recording, Slobodchikoff soon learned to discriminate between “Hawk!” “Human!” and so on.
He also discovered consistent variations in how prairie dogs use their alarm calls to evade predators. When a human appeared, the first prairie dog to spot the intruder gave a sequence of barks, which sent a majority of clan members scurrying underground. When a hawk swooped into view, one or a few prairie dogs each gave a single bark and any animal in the flight path raced back to the burrow. The presence of a coyote inspired a chorus of alarm calls throughout the colony as prairie dogs ran to the lips of their burrows and waited to see what the canine would do next. When confronted with a domestic dog, however, prairie dogs stood upright wherever they were, squeaking and watching, presumably because tame, leashed dogs were generally, though not always, harmless.
Something in Slobodchikoff’s data troubled him, however. There was too much variation in the acoustic structure of alarm calls, much more than would be expected if their only purpose was to distinguish between types of predator. So, he arranged for various dogs: a husky, a golden retriever, a Dalmatian and a cocker spaniel, to wander through a prairie-dog colony one at a time. The recorded alarm calls were still highly variable, even though the intruders all belonged to the same predator class. Slobodchikoff wondered, what if, instead of barking out nouns, prairie dogs were forming something closer to descriptive phrases? To find out, Slobodchikoff and three colleagues paraded through two prairie-dog colonies dressed in either jeans and white lab coats, or jeans and variously colored shirts: blue, gray, orange, green. The prairie dogs produced highly similar alarm calls for each person in the lab coat, except for one especially short researcher. But they chirped in very different ways for most of the different colored shirts. In a related experiment, three slender women differing in height by just a bit meandered through a prairie-dog habitat dressed identically except for the color of their T-shirts. Again, the animals varied their calls. And in another study, prairie dogs changed the rate of their chirping to reflect the speed of an approaching human, and they seemed to remember each call!
If prairie dogs had sounds for color and speed, Slobodchikoff wondered, what else could they articulate? So, he and his colleagues designed a more elaborate test. First, they built plywood silhouettes of a coyote and a skunk, as well as a plywood oval (to confront the prairie dogs with something foreign), and painted the three shapes black. Then they strung a nylon cord between a tree and an observation tower, attached the plywood figures to slotted wheels on the cord and pulled them across the colony like pieces of laundry. Despite their lack of familiarity with these props, the prairie dogs did not respond to the cutouts with a single generalized “unknown threat” call. Rather, their warnings differed depending on the attributes of the object. They unanimously produced one alarm call for the coyote silhouette; a distinct
warning for the skunk; and a third, entirely novel call for the oval. And in a follow-up study, prairie dogs consistently barked in distinct ways at small and large cardboard squares strung above the colony. Instead of relying on a fixed repertory of alarm calls, they were modifying their exclamations in the moment to create something new – a hallmark of language.
By the late 1990s, Slobodchikoff transitioned from studying paper sonograms to generating computer- based statistical analyses of the frequency, duration and harmonic structure of prairie-dog vocalizations. Based on such analyses, he said that the most crucial distinctions between prairie dogs’ calls are not in length or the number of discrete chirps but rather in the amplitudes of overlapping sound waves in each call, the composite of which is essentially their tone. Slobodchikoff makes an analogy to Mandarin: The word ma can mean “horse,” “mother” or “to scold,” depending on its intonation. Whereas the tone of human speech is typically determined by a fundamental frequency and just three or four overtones layered on top, prairie dogs can have six or seven audible overtones mingling in a single call. Slobodchikoff
thinks that by modifying these harmonics and combining them in different ways, prairie dogs form original descriptive phrases: dog big yellow fast; human small blue slow.
Why would a prairie dog need such specific information? “My guess is that these descriptions evolved to recognize and remember predators with different appearances and hunting strategies,” Slobodchikoff says. Coyotes, for example, have varying proportions of black, gray, white, red and yellow in their fur. One coyote might walk into a colony relatively nonchalant; some will charge a prairie dog and others lie down at a burrow, waiting for up to an hour to pounce. Indeed, some of the studies support the idea that prairie dogs remember individuals. In one experiment, black-tailed prairie dogs, distinguished human trespassers by height and T-shirt color and further produced a signature call for a person who repeatedly fired a 12-gauge shotgun into the ground.
Before 1800, as many as five billion prairie dogs lived throughout the Great Plains in colonies that collectively spanned more than 100 million acres. Today, by some estimates, the five prairie-dog species inhabit as little as one to two million acres total. Much like the bison, prairie dogs have declined in part because of sanctioned mass slaughter, not for their meat or fur but simply to eliminate what many people consider a pest. Ranchers have long held that cattle cannot thrive alongside prairie dogs because the two creatures compete for pasture. Studies suggest that such competition is generally negligible; it takes hundreds of prairie dogs to eat as much grass as a single cow. There is also a persistent notion that horses and cattle break their legs by tripping in prairie-dog burrows, though evidence is scant. Historically, white-tailed prairie dogs have been displaced from areas by grassland conversion to agriculture, urbanization, and oil/gas exploration and extraction, and have been negatively
impacted by habitat alterations due to livestock grazing and fire suppression. The Bureau of Land Management, which manages 56% of the white-tailed prairie dog gross range, has reduced stocking rates and improved range conditions in some areas, but upland habitats are difficult to restore and options for their restoration are limited.
They’re threatened by the same plague that caused the Black Death in Europe. Around 1900, another major threat to prairie dogs arrived on the West Coast. Trade ships from Asia brought rats infested with Yersinia pestis, the bacterium that causes the bubonic plague. Using fleas as an initial vector, Y. pestis didn’t just trigger an epidemic of plague in San Francisco; it escaped into the wild, eventually establishing itself in more than 76 mammal species. Prairie dogs are one of the most susceptible. Plague can wipe out an entire colony in a week, in part because they are so intimate and close-quartered. The disease is still rampant in large tracts of the region, and tends to wipe out entire prairie dog colonies when it strikes. There’s also sylvatic plague. Recently the flea-spread disease killed 70 percent of the prairie dogs in one
If Slobodchikoff is right about their language, to say nothing of all the other undeciphered clucks, yawps and bellows on Earth, then we will have been the cause of, and the indifferent witness to, the annihilation of a species that helped transform our understanding of animal minds. To recognize that we are not alone, that we share our world with other conscious, thinking, speaking beings, requires us to sacrifice a great deal of ego. At the same time, it folds us, palpably and inextricably, into the fabric of a much grander universe. As it stands, our greatest chance of achieving such a breakthrough may not require radio telescopes or interstellar travel but rather a new appreciation for a raucous rodent in our vast grassy backyard. Assuming, that is, that we don’t lose, or invent, anything in translation.
Since the ferret breeding program began in 1987, more than 3,000 black-footed ferrets have been raised at 11 facilities throughout the U.S. In Colorado, one such captive breeding facility exists in Browns Park and the facility has produced 34 ferrets since 1999. The reintroduction of black-footed ferrets into the wild began in 1991 in central Wyoming with the release of 228 captive-bred animals over a four-year period, have been released at eight sites in five states – Wyoming, Arizona, Utah, South Dakota, Montana – and in Mexico. Black-footed ferrets are totally dependent on prairie dogs for food and habitat, and use prairie dog burrows to raise their young. Wildlife biologists estimate that ferrets need between 5,000 and 10,000 acres of concentrated prairie dog habitat to survive. Prairie dogs inhabit about 15,500 acres inside the Wolf Creek area and 10,000 acres of 51,563 acres of Coyote Basin prairie dog town near Massadona, Colorado. When you visit Dinosaur National Monument for a river trip, spend a few days exploring. If you travel east on Highway U.S. 40 a few miles past Massadona you will see a wildlife viewing area sign that directs you to the Coyote Basin prairie dog town. Pull in and spend a few hours at sunset watching the show.
Biotics Database. 2005; Utah Division of Wildlife Resources, NatureServe, and the network of Natural Heritage Programs and
Conservation Data Centers.
Prairie dogs & Black-footed ferrets; U.S. Fish and Wildlife Service; Mountain-Prairie Region; Endangered Species Mammals
Prairie Dog Management; U.S. Fish and Wildlife Service; Charles M. Russell National Wildlife Management Study
White-tailed prairie dog; Utah Division of Wildlife Resources; Western Association of Fish and Wildlife Agencies
White-tailed Prairie Dog Conservation Assessment; Amy E. Seglund, Andrea E. Ernst, Martin Grenier, Bob Luce, Allison
Puchniak, and Pam Schnurr; January 2006
A Critical Review of Assumptions About the Prairie Dog as a Keystone Species; Natasha Kotliar, Bruce Baker, April
Whicker; Biological Resources Division, Midcontinent Ecological Science Center, US Geological Survey
Herm Hoops’ life has always been associated with water: from bucolic farm ponds and awe-inspiring rivers to the endless ocean, and he’s always had an interest in history.
Herm, the son of farmers, grew up on a large dairy cattle and Morgan horse farm. After attending the University of Vermont he taught Vocational Agriculture and Forestry in the Northeast Kingdom of Vermont.
He began running Western rivers in 1966. In 1972 Herm left Vermont and headed West for the better part of a year to run any rivers he ran across. In 1975 he began a career with the National Park Service and U.S. Fish and Wildlife Service. Herm retired from the Dinosaur National Monument in 1996, but he has continued following his love of rivers as a guide, naturalist, historian, and he is proactive in protecting the river canyons of the Colorado Plateau. Over the years he has been acknowledged for his contributions to a large number of river guides and books. Herm has written articles for historical journals and magazines. He is a lifetime member of the Colorado Plateau River Guides, the Grand Canyon River Guides and recently was made an honorary life member of the Utah Guides and Outfitters Association. Herm has served on the boards of several organizations, including Plateau Restoration and Conservation Adventures (Moab) and Colorado Plateau River Guides.
The rivers have been good to him, and perhaps, he has been good to them.
Herm and his wife Valerie live in Jensen, Utah.