About the rock chuck (yellow-bellied marmot)
Scientific name: Marmota flaviventris
Characteristics: Back is dark brown to black, belly is yellowish. Facial markings vary. Males typically outweigh females. Adult males range from 6½ to 11½ pounds and adult females range from 3½ to 9 pounds. Males average about 24 inches from head to tail tip, females 22 inches. Tail is about 3 to 5 inches long. Rock chucks have the thickest build of the genus, which includes groundhogs.
Habitat: Prefer meadows next to rock outcrops. Live in burrows under rocks, with entrances about 6 inches wide.
Habits: Spend about 80 percent of life underground. Hibernate about eight months out of the year, between August and March, depending on elevation. Live alone or in colonies of two to eight animals, with the colonies consisting of one male, several females and young.
Food: Mainly plants, such as grasses, forbs, flowers and seeds, but also some insects and bird eggs.
Sources: U.S. Fish and Wildlife Service, High Desert Museum, Smithsonian National Museum of Natural History
The plump, oversized ground squirrels now making an appearance on the grass below the rock wall along Southwest Bond Street at the Old Mill District would be called different things if they traveled around the West.
The names vary from whistle pig — they do whistle — to potgut — they do have a potbelly — says John Goodell, curator of natural history at the High Desert Museum. Here the animals are known as rock chucks, and in the biology books they are known as yellow-bellied marmots, or by the scientific name Marmota flaviventris.
“There’s all kind of local vernacular depending on where you are,” he said.
But you likely won’t see any rock chucks setting off for a trip around the region.
They like to keep it local and stay close to their burrows, holes they’ve dug under rock piles like those by the Old Mill and elsewhere around Central Oregon.
“It seems to work well for them,” said Mike Bjorvik, landscape superintendent at the Old Mill.
While some people consider rock chucks a pest because their digging can leave holes in lawns, Bjorvik said they are not a huge problem at the Old Mill.
The rock chucks there even have an unofficial fan club, with someone Tweeting and posting on Facebook as the animals. The rock chucks, or at least their online persona, refused to comment for this story.
The real-life rock chucks also like to be underground. Rock chucks are in the same genus as the groundhog, which is found in the Eastern United States and Canada, and hibernate throughout fall and winter. Between hibernation and daily trips into their dens, rock chucks spend about 80 percent of their lives underground, Goodell said. Now is the time to spot them above ground.
“The best viewing times are right now, between now and June,” Goodell said.
Over the past month the rock chucks have come out of hibernation in Central Oregon and may regularly be spotted munching on lawns. When above ground, they spend much of their time eating and fattening up for the next hibernation.
“You’ll find that they will be fatter in the fall than they are in the spring,” said Simon Wray, a conservation biologist with the Oregon Department of Fish and Wildlife.
Goodell said rock chucks are omnivores, or animals that eat both meat and greens. Most of their diet is grass, forbs and other plants, but they will also chow on grasshoppers and bird eggs.
Male rock chucks are bigger than females, with adult males weighing 6½ to 11½ pounds and adult females weighing 3½ to 9 pounds, he said. Rock chucks typically live 13 to 15 years in the wild.
A quirk about the Central Oregon rock chucks is where they’ve picked to live. In other parts of the West they prefer terrain above 6,500 feet, Goodell said. Bend is well below that at 3,623 feet, and the rock chucks don’t seem to mind the lower elevation or the city around their habitat.
Wray said there are no concerns, such as habitat loss or population decline, about rock chucks in Central Oregon, although a formal survey hasn’t been done.
“There are no issues with yellow-bellied marmots,” he said. “They seem adaptable enough that they can live in town.”
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