The upland and lowlands rainforests of southwestern Sri Lanka are notable for their exceptionally high rates of endemism, i.e. the proportion of species found nowhere else on earth. In terms of small mammals, the Sri Lankan moist forests support a very high number of globally threatened eulipotyphlan insectivores (7 species). Two of these, Pearson’s long-clawed shrew (Solisorex pearsoni, EN) and Kelaart's long-clawed shrew (Feroculus feroculus, EN) are the sole representatives of two eulipotyphlan genera found only in Sri Lanka, along with a third endemic monotypic genus represented by the Ohiya rat (Srilankamys ohiensis). Other small mammal species that are either endemic or ‘near-endemic’ to this region are the Asian highland shrew, Sri Lankan Long-tailed Shrew, Nillu Rat, Ceylon Spiny Mouse, Layard's palm squirrel, Dusky palm squirrel, Travancore Flying Squirrel and the Nolthenius's Long-tailed Climbing Mouse.

Threats to this small mammal fauna is primarily from habitat loss and degradation. The majority of Sri Lankas rainforests have been lost to rice paddies, housing, and plantations of tea, rubber, and coconut. Remaining fragments are still being cleared for agriculture.

Half of the remaining southern lowland forests are protected in the Sinharaja Natural Heritage Wilderness Area. In the montane forests, five protected areas exist but none have good protection measures or conservation plans in place.

Our knowledge of the small mammal fauna of this region is extremely limited. Only one Data Deficient species is known from this Key Region.