The diminishing lowland and upland rainforests of Sumatra and its surrounding islands, particularly the Mentawi Islands, are home to a very high density of globally threatened small mammal species. The overall small mammal fauna is dominated by squirrels (24 species) and murid rodents (32 species) as well as tree-shrews (8 species). A distinctive feature of this diversity is the large number of globally threatened and Data Deficient flying squirrels and squirrels, such as Black Flying Squirrel Aeromys tephromelas, Whiskered Flying Squirrel Petinomys genibarbis, Smoky Flying Squirrel Pteromyscus pulverulentus and Fraternal Squirrel Sundasciurus fraterculus. Just two AZE trigger small mammal species are found on Sumatra - the Sipora Flying Squirrel Hylopetes sipora of Sipora Island (west coast of Sumatra) and the Sumatra Water Shrew Chimarrogale sumatrana of Pagar Alam. In terms of eulipotyphlan insectivores, the Vulnerable Dwarf Gymnure Hylomys parvus can be found on the slopes of Mount Kerinci on the west coast of Sumatra.

Between 65% and 80% of Sumatra’s lowland and montane forests have been lost to logging and agriculture – predominantly oil palm plantations. Sumatra is probably losing its forest habitats faster than any other part of Indonesia as, despite legal protection, forest is still being cleared today.

Like in Borneo, multiple national and international NGOs are working to try and save Sumatra’s remaining forests to benefit both wildlife and people. Its vital that the needs of many tens of globally threatened small mammals are taken into account in these large-scale forest conservation initiatives. This includes NGOs such as WWF working with major investors to stop or restrict financing of palm oil plantations across Indonesia.

Like many of our Key Regions, Sumatra’s small mammal fauna is poorly known. With 12 Data Deficient species on Sumatra, the priority is to understand more about their distribution and population history so we can assess extinction risk, as well as research to understand more of the ecology of the globally threatened small mammal species.