Marmots are the largest member of the squirrel family. There are 15 species of marmots found across North America, Asia, and Europe. Yellow-bellied are one of six species found in North America.
Yellow-bellied marmots are widely found in southwestern Canada and western United States. They typically live in mountainous and semi-arid (very dry) areas.
At our study site near Gothic Colorado, about 50 percent of marmots do not make it to their first birthday. Those that do typically live to be 3 to 5 years old. Our oldest female lived to 16 while our oldest male lived to be 11.
Yellow-bellied marmots are about the size of an average house cat. They are typically about 18-24 inches (46-61 cm) long and, in the late summer, weigh about 10 pounds (4.5 kg).
They’re vegans! Formally, yellow-bellied marmots are generalist herbivores meaning they eat many different plants such as grasses, forbs, and flowers. Fun fact - Marmots don’t drink water! They get all their water from the plants they eat.
Baby marmots are called pups. They are usually born from March to June, depending on elevation. At our study site, pups emerge from their burrow between mid to late June to mid July. Yellow-bellied marmots typically have about 4 pups in a litter, however we have seen litters as small as 1 pup and as big as 9 pups!
Marmots are the largest true hibernator. Hibernation is a controlled/voluntary state that an animal enters to survive winter or when resources are low. While hibernating, animals will lower their body temperature, heart rate, and metabolism (how fast their body turns food into energy). Yellow-bellied marmots will start hibernating in late September and wake up in April or early May. During this time, the marmots rely only on their stored fat to survive and is why getting fat is essential to their survival!
Yellow-bellied marmots are important summer food for the carnivores they live with. Also, depending on where they live, they can be important for controlling plant populations.
Yellow-bellied marmots are currently neither threatened nor endangered. This makes them perfect for our long-term study on factors that drive changes in population size.