Because the Dwarf Shrew is so small, it doesn't trigger the older snap or box traps, and before 1966, only 18 specimens had been collected. With the use of pitfall traps, which are basically cans sunk into the ground so that the animal tumbles in and cannot jump out, many more Dwarf Shrews have been trapped and more has been learned about their distribution, but its range may still be more extensive than has been recorded. Learn more about the Sorex nanus, more commonly known as a Dwarf Shrew, in this easy-to-read species overview by the Smithsonian's National Museum of Natural History.