Shrews are burrowers that inhabit forests, marshes, and scrub growth. They prefer moist environments and dig tunnels in the humus layer of the soil. Their nests can be found under logs and rocks, and they have been known to borrow existing tunnels from moles from time to time. Shrews are insectivores that live off insects, spiders, worms, and land snails. Shrews can be very aggressive. They have been known to attack an animal larger than they are, such as a garter snake or young hare.
Shrews are primarily nocturnal and get around using echolocation like a bat. This allows them to hunt underground or aboveground. Shrews are also solitary animals that defend their territory. The northern short-tailed shrew is a venomous mammal that can paralyze and kill a mouse with a single bite.
Since shrews are active year-round, they can dig tunnels around your home and damage your landscaping, even beneath the snow. Unlike moles, they regularly leave their burrows to hunt. This makes the entry points easy to spot. With a diameter of 3 to 5 cm, they are usually located near a vertical surface such as a wall or fence.