At around two grams, the American pygmy shrew is the lightest mammal in North America, weighing roughly as much as a dime. Ohio has only 11 confirmed records since 2000, the lowest count of any species on this list, which is as much a reflection of how genuinely hard an animal this size and this secretive is to detect as it is a measure of scarcity.
NatureServe ranks it S1, critically imperiled, in Ohio. Its metabolism runs so fast it must eat almost constantly, spending its brief life tunneling through leaf litter at forested sites like Cuyahoga Valley National Park and Wayne National Forest, rarely surfacing where a person would ever see it.


