This past winter, I had the privilege of working in Yellowstone National Park, where I befriended some of the local winter wildlife. This included the American pine marten.

Under normal circumstances, this animal is curious but elusive — except when it came to trash compactors and then they were not shy about showing their cute little faces. They would often jump out when I opened the doors or played in the snow, chasing each other around the machines.

For those who have never seen a pine marten, it is described as a cat-like creature with rounded ears, almond shaped eyes, a bushy tail and a long, slender body. Though they are not related to cats, they do sound like angry cats when enraged. The marten is about 18 to 27 inches in length from nose to tail, and its bushy tail is about 1⁄3 of its body length, aiding in balance and agility.

These animals range in color from light tan to dark brownish-black. On their bellies is a small dot to large patch that is cream colored to orange. They also have strong claws and furred feet, which allows for quick climbing, and snowshoe-like paws in the winter months.

American pine martens are active year-round, due to their primary food sources being active year-round. With their furred paws, they are able to walk or run across the top of the snow with ease. Martens are primarily carnivorous, commonly eating small mammals such as voles, red squirrels, mice and hares, but also eating birds, eggs, amphibians, reptiles, insects, carrion and occasionally vegetation and berries.

In the summer months, they have even been observed in alpine areas in search of pikas and marmots. They eat two to three rodents per day, and although it does not sound like much, it is an equivalent of a 60-pound child eating 100 quarter-pounders per day — a lot of food for a small body.

Martens eat a lot because they are constantly on the move, covering a 1- to 3-square-mile territory in about a week. During mating season, they build nests or dens in dead trees, which the females line with grasses or leaves. Breeding and mating usually occur in July or August, and litters of two to four young are born in March or April.

Newborn infants weigh about 1 ounce and are blind and nearly naked. Between six and seven weeks, these newborns open their eyes, wean from a milk diet to meat and begin to hunt with mom. When the newborns reach 3 months old, the mother will re-enter fertility and leave her children.

These agile animals are threatened by localized endangerment or possible extinction. Like most animals, they have natural predators such as coyotes, foxes, lynx, bobcats and mountain lions, but humans are their biggest threat due to deforestation, wildfire remnants and trapping for fur.

The American pine marten is considered a species indicator due to its dependence on mature coniferous forests across the northern United States, Canada and Alaska. A species indicator is a species that is affected by changes in their environment, and changes in their populations can indicate a problem with the ecosystem. These animals prefer old-growth forests for denning sites, food sources and overall protection, but they can also be seen in man-made structures, especially when food is more prevalent.

As you plan to enjoy the Vail area this winter, keep your eyes open for this curious creature. If you are unable to spot them in the forest, then cautiously check the communal trash dumpsters. You never know, you may be in for a surprise.

Alicen Well is a naturalist with Walking Mountains Science Center but worked as a recycling technician in Yellowstone National Park for nine months, befriending the pine martens that frequented the trash compactors and despising the clever ravens that terrorized her daily.