Lemmus is a genus of small rodents commonly known as lemmings. These animals are found primarily in the Arctic and subarctic regions, where they inhabit tundra and grassland environments. Lemmings are known for their short tails, compact bodies, and thick fur, which helps them survive in cold climates. Lemmings play a crucial role in their ecosystem as a food source for various predators, including arctic foxes and snowy owls. They are also known for their unique population dynamics, which can lead to dramatic fluctuations in their numbers every few years.