Three of the last five large mamals to be discovered world-wide occur in the area.
Nakai Nam Theun is a global stronghold for four threatened primates including Red-Shanked Douc, Pygmy Slow Loris, Francois Langur and White-cheeked Gibbon.
It is home to some 430 bird species, Asian elephants and many more species.
NNT-NP is of national and global significance for several mammal species, including some of the world’s most recently discovered species that are endemic to the Annamite mountain range: Annamite Striped Rabbit, large-antlered muntjac, and the Saola (first camera trapped in 1998 in Vietnam and a few months later in Lao PDR).
At least nine primate species live in the area: Pygmy Slow Loris, Bengal Slow Loris, Rhesus Macaque, Assamese Macaque, Pig-Tailed Macaque, Bear Macaque (or Stump-Tailed Macaque), Red-Shanked Douc, Southern White Cheeked Gibbon, and one species of globally threatened Francois Langurs’ group, which is localised in the area, associated with rocky cliff sites.
The area has several carnivores including Dhole, Marbled Cat, Clouded Leopard, and Asiatic Golden Cat. Leopard (Panthera pardus) and Tiger (Panthera tigris) haven’t been recorded since 2009, unfortunately.
Elephants, Bears, Ungulates and Pangolin
The park has an estimated population of elephants of more than 100 individuals. Other notable mammal species include Sambar Deer, Gaur, Southern Serow, two species of bear, Asian Black Bear and Sun Bear, two species of pangolins, Sunda Pangolin and Chinese Pangolin.
Bird species confirmed in the area total 403. This makes the protected area one of the most important areas for birds in Lao PDR and Indochina. The protected area holds populations of near threatened Crested Argus and five recorded species of hornbills including Rufous-necked Hornbill, Brown Hornbill, and Great Hornbill (Wreathed Hornbill and Oriental Pied Hornbill have not been seen since the first field surveys).
Reptiles & Amphibians
Reptile and amphibian communities of NNT NPA are very little known as they remain for the rest of Laos. Of particular importance are Indochinese box turtle, Keeled box turtle, Yellow Tortoise, Impressed Tortoise, and Lao Salamander. The demand for some species of turtles is very high; they are hunted for food or trade.
Fish species that have been recorded from the plateau total 69 including some that were newly described to science and others endemic to the area, including the Pa Kang (Hemibagrus wykooides).