Lake Trout (Salvelinus namaycush)

Grand Teton National Park (GTNP) is known for its trout fishing. In the park, lake trout are quite the thrilling catch, weighing up to 60 pounds! They go by many nicknames – paperbelly, lake char, mackinaw – and are the largest species in their genus, Salvelinus. These fish are non-native in GTNP, but their environmental impact seems to be less drastic here than in Yellowstone Lake nearby.

The Great Lakes in Michigan and Yellowstone Lake have opposite problems when it comes to lake trout. Overfishing and the introduction of invasive lamprey dangerously thinned the native lake trout population in the Great Lakes in the 1950s. Conversely, after their introduction to Yellowstone in 1890, lake trout populations exploded and devastated the native cutthroat trout population in Yellowstone Lake, causing far-reaching damage to the lake’s natural ecosystem. Huge efforts in both the Great Lakes and Yellowstone Lake have been made to correct these population counts.

Written by Shawna Wolf
PC: YNP on Flickr https://flic.kr/p/pe6WeX

North American Deer Mouse (Peromyscus maniculatus)

The deer mouse—named because the fur color pattern resembles that of a white-tailed deer—is an extremely common mammal in North America, including the U.S., Mexico and Canada. This little guy can live in so many environments that, whether it’s prairie land or alpine areas, there is no wonder there are so many of them. However, deer mice do not thrive in cold, harsh winters, like those in Grand Teton National Park. Weighing in at under an ounce and just about 3 inches long fully grown, deer mice burrows do not take up much room at all. Female mice have up to 11 pups, depending on how many previous litters there were, and they reach maturity at just 35-50 days old.

Deer mice are known to be busy and social members of the ecosystem. These tiny mammals are nocturnal and spend most of their nights climbing or swimming around to eat and gather food. Mice eat insects, fruit, flowers, seeds, and plants that they collect daily in quantities as big as half a liter. Because they are transporting seeds and caching them, mycorrhizal fungi spores depend on this process to survive. Mice also help out the top of the food chain by being food for birds, snakes, and many mammals. They are still a primary carrier of the fatal hantavirus, and humans are at risk of contracting it, so be careful if you see a nest or burrow—check out this website about hantavirus information below.

Written by Celia Karim
PC: J. Maughn on Flickr https://flic.kr/p/2hUG8Ld

Sources: http://animalia.bio/deer-mouse,
Hantavirus info: https://www.nps.gov/grte/planyourvisit/hps.htm

American Red Squirrel (Tamiasciurus hudsonicus)

The American red squirrel is the only native tree squirrel in Wyoming, and they are quite abundant in mountainous coniferous forests across the United States. Their favorite activity of caching and dispersing seeds and nuts eludes to the first part of their scientific name, which means ‘treasurer squirrel.’ Besides seeds, they also eat fruit, mushrooms, insects, young rabbits, birds, and mice. These guys have red-grey fur with white fur on their bellies and around their eyes. Adult female squirrels usually have about five pups in a litter during the spring and have been found to raise their young in areas where aspen trees are common. Fully grown squirrels are about a foot long and weigh 7 oz.

Red squirrels benefit their ecosystem in many ways. They are vital to the reproduction of many plant species because when they store and bury seeds, the seeds often end up eventually sprouting. Grizzly bears depend on squirrels because they find the squirrels’ larger winter foodbanks and eat the fatty, protein-rich whitebark or limber pine nuts. The red squirrel is a keystone prey species for many animals including bears, weasels, hawks, owls, wolves and coyotes. They make a good chase because they are fast, nimble climbers, and they also have a loud warning chirp to protect their territory from other squirrels or predators. In Wyoming, a small game license is required to hunt the red squirrel. However, they feed on coniferous pine cones so much that these small squirrels are known to taste like turpentine to people.

Written by Celia Karim
PC: Anne Guzzo

Northern Sagebrush Lizard (Sceloporus graciosus graciosus)

The northern sagebrush lizard is the only known lizard species in the Greater Yellowstone Ecosystem (GYE) and was discovered in 1922 in Grand Teton National Park (GTNP). These reptiles grow to be 5 inches long, are grey or brown with dark stripes all the way from their heads to their tails, and have light colored bellies. Males have a longer tail than females and have some blue coloring on their underside and throat. They live in dry rocky environments up to 8,500 ft in elevation and like sagebrush ecosystems. These lizards also live in places with geothermal activity—hence living in Yellowstone National Park in addition to non-geothermal GTNP. Since they are cold-blooded, lizards are most active during the day so they can eat insects and bugs and bask in the sunlight. They take shelter mostly near the ground in old burrows, logs, plants, and rocks, but are sometimes found up in trees. The northern sagebrush lizard makes a tasty meal for snakes and birds of the GYE, so they have adapted to shed their tail to survive an attack.

Females lay about 4 leathery eggs in early summer that are 12 by 6 millimeters in size. Eggs are buried under loose soil by their shelter sites. Females usually lay eggs twice a year, but they can start reproduction at just 22 months. Baby lizards are only 2 centimeters long, and some hatchlings are even food for adult lizards. The northern sagebrush lizard lives for about 6 years and has a 50% chance of survival once they are hatched. You can see these lizards in GTNP at the Snake River Floodplain, Pilgrim Creek, Bar BC Ranch, and Colter Bay.

Written by Celia Karim
PC: Angie Shyrigh on Flickr https://flic.kr/p/5x2uRV

Mountain Lion (Felis concolor)

Known colloquially as a cougar, puma, panther, or catamount, the mountain lion (Felis concolor) is basically a smaller jaguar without spots. It is unlikely that you will ever see a mountain lion in the Greater Yellowstone Ecosystem (GYE) because they are nocturnal and typically avoid anything besides prey, but it is smart to be informed about predators when visiting. Beware of these indications that you are in mountain lion territory: long scratches on trees, remains of a carcass, piles of dirt or leaves/debris scraped up by back feet, large amounts of scat containing hair or bones, and round paw prints with no claw marks. These signs are often found in areas the mountain lion may return to, especially the carcass.

Mountain lions do not have a set mating season, but they will typically have up to 6 cubs every two years. Newborn cubs weigh just under a pound and have dark spots all over their fur that they outgrow as adults, giving way to pale brown fur with white highlights on their underside and head. Cubs will stay with their mom for about a year and a half or until they can fend for themselves. While hunting, a male mountain lion can travel 25 miles in a day. In the winter, mountain lions might follow other animals (aka their food) and move down to lower elevations. Mountain lions have a lot to eat in GYE including deer, bighorn sheep, birds, porcupines, fish, insects, rodents—sometimes pets and livestock, too.

By the 1920s, predator control in GYE took the lives of thousands of mountain lions until there were less than 15 left. Today, there are about 120 cougars in GYE that are being researched as part of the Panthera’s Teton Cougar Project to learn more about the population, interactions, and habitat of this secretive stalker. They are skilled athletes and can land a jump from 60 ft high even though they weigh about the same as a human—200 lbs. This is one fascinating animal you might be okay missing in GYE!

Written by Celia Karim
PC: Yellowstone National Park on Flickr https://flic.kr/p/2fKKuFu