Small Mammals of Mainland Southeast Asia

An illustration of a striped rabit from the book Vietnam Vietnam: A Natural History.

Striped rabbit (Nesolagus timminsi), an illustration from the book Vietnam: A Natural History. © Joyce Powzyk

The Center for Biodiversity and Conservation's integrated research, conservation, and capacity building efforts in Mainland Southeast Asia incorporate a strong focus on small mammals. This collection of diverse species includes moles, shrews, bats, squirrels, mice, rats, pikas, and rabbits; groups that are among the region's (and the world's) most diverse yet least studied mammalian groups. Our work is focused in the adjacent countries of Vietnam and Lao PDR (Laos), which lie in the heart of the Indo-Burma Biodiversity Hotspot, an enormous and geographically complex area south of China recognized for its globally significant levels of biodiversity. Vietnam and Laos are home to the southern and eastern-most extensions of the Himalayas as well as a number of unique habitats, including isolated mountain ranges (such as the Annamites), complexes of limestone (karst) outcroppings, and enormous river systems (the Red and Mekong Rivers) with their associated deltas.

Despite a long history of regional explorations dating back to the 19th century, a large gap remains in our knowledge of both the species diversity and natural history of Mainland Southeast Asia's small mammals. Among the fascinating recent small mammal discoveries coming from Vietnam and Laos are a striped rabbit (Nesolagus timminsi), whose closest living relative is restricted to the hills and mountains of Sumatra, and a "primitive" rodent (Laonastes aenigmamus), the only known extant member of a rodent group previously believed to have gone extinct 11 million years ago. Our lack of basic information is made more pressing by the severe threats from human-induced impacts now bearing on the region's habitats and species. Land use practices have dramatically lowered the amount of forested area, which is increasingly being converted to agricultural areas, and the remaining forests are threatened by sophisticated hunting and trading practices, which have decimated local populations and extirpated species from large areas of Indochina. In addition, small mammals have largely been left out of regional conservation decision-making processes in favor of better-known plants and animals.

Beginning in 1998, researchers from the CBC, in collaboration with scientists and conservation workers from Asia, Europe, and North America, five sites in Vietnam and Laos. This work has documented both previously undescribed species and species recorded for the first time in Vietnam. New descriptions include two new species of shrew (Chodsigoa caovansungaCrocidura kegoensis) and both new genera and species descriptions for two rats (Saxatilomys paulinaeTonkinomys daovantieni). New country records include a shrew (Blarinella griselda) and the rarely documented Long-tailed Mole (Scaptonyx fusicauda), previously known only from central China and the Tibeto-Himalayan region. The newly described rats are part of a suite of recently described small mammals (e.g., Hylomys megalotisL. aenigmamus) adapted to the harsh, rocky environments of eroded limestone hills. Although long recognized as centers of plant, invertebrate, and bat diversity, these new discoveries indicate that the isolated karst outcroppings of both Vietnam and Laos are also home to a unique community of small terrestrial mammals as well. The CBC's small mammal surveys also contribute to conservation decision-making by assessing the health and integrity of forested ecosystems where large mammal numbers have been reduced by hunting. Finally, in addition to surveying regional species diversity, CBC researchers have contributed to organizing, documenting, and conserving older small mammal collections held in Vietnam, including the publication of a taxonomic guide to the country's rodents.

The CBC has been engaged in research in Mainland Southeast Asia since 1997, partnering with the Institute for Ecology and Biological Resources (Hanoi) and dozens of additional international universities and museums, as well as non-governmental conservation organizations including the IUCN, World Wildlife Fund (Greater Mekong Programme), Birdlife International (Indochina), Fauna and Flora International (Indochina), the Vietnam Environmental Network, and Wildlife Conservation Society (Lao PDR).

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