Eurasian Least Shrew: Japan’s Smallest Mammal
The Eurasian least shrew (Sorex minutissimus hawkeri), also called the Tokyo shrew, is one of the smallest mammals in the world. An endangered species, it measures just 5 centimeters from nose to tail. It lives in the grasslands and wetlands around Kushiro, feeding on insects.
Shrews resemble mice but are more closely related to moles and hedgehogs. The Eurasian least shrew is one of four species of shrew unique to Hokkaido.
The name “Tokyo shrew” arose from a simple labeling mistake. When the Eurasian least shrew was discovered during the Meiji era (1868–1912), a specimen of the shrew was labeled “Ezo,” referring to Hokkaido. However, it was later misread as “Edo,” the old name for Tokyo, and the name stuck.