Unlike migratory species, Arctic shrews live in the Arctic year-round. They're solitary animals, who live about a year and a half in the wild. They eat bugs—like grasshoppers and sawflies—and help regulate pest populations in the ecosystem.
The masked shrew is expanding its range as the climate warms. (Phil Myers via Creative Commons)
The pint-sized mammals are known for carrying both external and internal parasites, which make them a key link in the Arctic ecosystem. It also gives researchers insight into changes happening on the tundra.