Thomas' Small-eared Shrew is a small shrew of the Colombian Eastern Cordillera. It has tiny ears and eyes and is recorded in humid mountain forest and páramo.
It is reported at about 8 cm long, with ears hidden in the fur, very small eyes, a short tail, and red-tipped teeth.
The Carpanta Biological Reserve study recorded two well-developed embryos on dissection of pregnant Thomas’s shrews. The observation documented reproduction around 3,000 metres in the Colombian mountains.
During February–August 1989, researchers trapped animals across forest, páramo and their boundary and assessed reproductive condition using pregnancy and mammary-development indicators. Pregnant Thomas’s shrews were recorded in July and August.
The shrews’ activity centres were more frequent in páramo, rather than evenly spread across the grid. Captures also occurred at the forest boundary, placing this transition zone within their local habitat.
An extinction-risk assessment has not been added yet.
The 2023 inventory that recorded the species in Soacha recommended protecting remaining Andean forest and maintaining connections with other forest fragments. These are regional conservation proposals for the mammal community.