げっ歯類はげっ歯類ですよね？確かに—たとえそれらが必ずしもあなたの考えのように見えなくても。もちろん、ネズミ、リス、ハムスター、そして巨大なカピバラもあります。それらはすべてげっ歯類ですが、何も似ていません。それからプレーリードッグがいます。彼らの名前にもかかわらず、彼らはまったく犬ではありません。実際、彼らもげっ歯類です。
一見すると、リス（リス科）の家族の一員であるぽっちゃりした小さな生き物は、モグラたたきのようなゲーム（もちろん木槌はありません）の一部である可能性があるように見えます。彼らが地面に掘る穴。
しかし、どのアーケードでもプレーリードッグは見つかりません。あなたはアメリカの中西部の平原の草原でそれらを見つけるでしょう。そして、彼らは穴から飛び出す以上のことをします。実際、彼らはとても賢い動物です。
プレーリードッグの生息地とライフスタイル
There are five species of prairie dog: black-tailed, Utah, Mexican, white-tailed and Gunnison. All are small animals and range between 12 and 17 inches (30 and 43 centimeters) long and weigh in at between 1 and 3 pounds (0.45 and 1.3 kilograms). Depending on the species, they have shades of brown, black, tan, white and gray fur and short tails. These relatives of the squirrel are very social animals and excitedly greet each other with what appears to be hugs and kisses.
They live in little coterie groups of one or two males, several breeding females and the new pups that result from this living arrangement. Males go from coterie to coterie, but females stick together for life. Females are only in estrus for one hour a year. Their life span is about five to eight years. The truncated mating season leaves a lot of time for digging burrows that lead to prairie dog towns.
Tens of thousands of prairie dogs live in large intricate underground burrows, called towns. Towns are divided into family coteries. Each coterie covers about an acre (0.4 hectare) and contains separate rooms for sleeping, rearing young (the pups are born here and remain for about six weeks) and eliminating waste — the prairie-dog versions of bedrooms, nurseries and bathrooms. All dogs in a coterie have specific duties, such as foraging, interacting with others (this must be the most popular duty), maintaining burrows or looking for unwanted guests.
You can recognize a prairie dog burrow by the piles of dirt that sit above ground next to each entrance. The piles provide prairie dogs warmth in the winter and help keep burrows from flooding. They also function as footstools that give the small mammals a better vantage point to spot predators, including eagles, hawks, owls, ravens, coyotes, badgers, ferrets and snakes.
They Have an Advanced Vocabulary
Prairie dogs have an impressive communication system and use it to warn other town-dwellers of danger. To us, these repetitive sounds might seem like simple squeaks. But they're much more than that. When a prairie dog sees a predator, he makes a sharp warning sound and bobs up and down excitedly, and follows that up with a second sharp sound. He then dives into the burrow and continuously lets out a two-syllable bark (hence the name prairie "dogs") at the rate of 40 barks per minute.
Other town members watch from farther away and alert the others of the intruder's route and proximity.
Clint Lusardi, San Diego Zoo animal care manager, explains that a prairie dog not only alerts others that a human is coming, but they also use different vocalizations to distinguish between "a human," and "a human with a gun."
"To me, that's the most interesting fact about prairie dogs. They've learned that a human with a gun is a threat," Lusardi says.
In 2011, animal behaviorist and language specialist Con Slobodchikoff, Ph.D., even proved the little rodents used different calls and barks to distinguish between humans wearing a blue shirt from humans wearing a green or yellow shirt.
When two coteries cross paths, there can be some serious tension that results — think of it like the prairie dog version of chest pounding. Showdowns can include up to 30 minutes of staring, teeth chattering, tail flailing and sometimes fighting.
Prairie Dogs Are a Keystone Species
Prairie dogs are mainly herbivores and eat grasses, seeds, roots and any leafy plants they can find, as well as the occasional insect. They are diurnal and spend most of the day searching for food. They clear the area around the burrows of all the tall plants and grasses, which makes it harder for enemies to sneak up on them.
Biologists consider these rodents a keystone species that benefit approximately 150 other species. Their towns offer cover to toads, small rabbits and rattlesnakes and the ground they clear attracts insects that feed birds. They also provide nitrogen-rich waste that fertilizes soil and plants. And sometimes — when there's a breakdown in that elaborate communication system — they do end up as food for their predators.
But not everyone considers prairie dogs as cute, harmless little animals. Ranchers and farmers consider them as pests that compete with their livestock for food. They're also a safety hazard. Montana rancher Hank Swan knows firsthand how problematic they can be. "We've lost a lot of cattle; they step into prairie dog holes, break their legs and have to be put down," he says. "This is how we make our living and it's a significant loss."
The idea that these rodents are pests has been a big part to their decline. In the early 1900s, there were about 5 billion prairie dogs across western North America, since then the population has decreased by about 98 percent, and about 100 million remain. The population has been decimated due to plagues, poisonings, shootings and bulldozing. The Utah and Mexican prairie dogs are currently listed under the Endangered Species Act as threatened and endangered, respectively, but the other species are not, and are instead being monitored constantly.
Now That's Awesome
Prairie dogs can create new "terms" for things they've never seen before and are thought to have one of the most sophisticated communication systems of any animal.
