Searching for Shrews

Photo Caption: This short-tailed shrew captured in north Florida is similar in appearance to the enigmatic Sherman’s short-tailed shrew of southwest Florida. 

By Chris Winchester and Jeff Gore

Short-tailed shrews (Blarina carolinensis) occur throughout Florida, but individuals in Collier and Lee counties in south Florida are larger and they are considered to be a separate species known as Sherman’s short-tailed shrew (Blarina shermani). Little is known about this shrew because it has seldom been observed, in fact the distribution and taxonomy of this species are based primarily on several specimens collected at a few locations in the 1950’s.

To determine the current status of Sherman’s short-tailed shrews, FWRI biologists initiated a study using drift-fence arrays set on public lands within the shrew’s presumed range in southwest Florida. Drift-fence arrays are a common method for capturing shrews and they consist of silt fencing erected to direct shrews and other small animals into pitfall buckets sunk into the ground along the fence. Despite an extensive survey effort involving 63 drift fence arrays and more than 23,900 trap days (1 pitfall trap set for 1 day), biologists captured only 3 short-tailed shrews. Over that same survey period, they captured more than 250 least shrews (Cryptotis parva).

These results show that although short-tailed shrews are still present within the presumed range of Sherman’s short-tailed shrew, they are either quite rare or very difficult to detect compared to other shrews. The next step is to work with partners to compare DNA from the 3 recently collected specimens to DNA from previously collected specimens to determine if the recently trapped shrews are indeed Sherman’s short-tailed shrews and just how genetically unique these shrews are from other short-tailed shrews.