Northern short-tailed shrew (Blarina brevicauda) is the only poisonous mammal on the North American mainland. Its poisonous bite allows it to paralyze its prey and eat it at a later time. It is sufficiently strong to kill animals up to the shrew’s size, and to produce a very painful reaction in humans who handle the shrew.
It has a poor sense of smell and very poor vision. It can navigate and detect objects in its environment using echolocation and and touch. Like bats, it emits a series of ultrasonic squeaks to detect its surroundings. Unlike bats, it does not use echolocation to locate prey. Its snout and whiskers are highly sensitive to touch.
There are 385 species of shrew worldwide, 7 in Minnesota. Northern short-tailed shrew is the largest and most widespread in eastern North America and the most common in Minnesota. The combination of large size and short tail distinguish this from all other shrew species in Minnesota.