Sri Lanka - a world Reptile HOTSPOT

Sri Lanka
Sri Lanka

Sri Lanka is a humid tropical island lying in the South Asian region, southwest of the Indian peninsula, in the Indian Ocean, between latitudes 5º 55' and 9º 51' N and longitudes 79º 41' – 81º 54' E. During the late Miocene period, a section of the Tethys sea (the existing Palk strait and Gulf of Mannar) detached the extreme portion of mainland India and turned Sri Lanka into an island. The island is 65,610 km2 in area, of which 64,742 km2 is land and the remainder is inland water.

When considering the geography and topography of the island, three peneplains or erosion levels are recognized by their height and slope features. The first peneplain is the largest of the three and extends from sea level to 270m above mean sea level (m.s.l.). The Uplands or the second peneplain extends from 270m to 900m above m.s.l. and the Highlands or third peneplain at 900–2420m. The island has also been divided into four climatic zones based on rainfall. The Dry zone occupies ~60% of the total land area of the country. Its annual rainfall is between 1250-1900 mm and its mean annual temperature ranges 27 – 30ºC. It is characterized by monsoon forests and thorn scrublands. The Wet zone, which covers approximately 23% of the total land area receives a rainfall of 2500–5000 mm per year. It consists of lowland evergreen forests, montane rain forests and semi-evergreen rain forests. The transition zone between the above two zones is known as the Intermediate zone where the annual rainfall varies between (approx.) 1900–2500 mm. The two semi-arid zones in the South-east and North-west receives less than 1250 mm of rainfall per year.

Although Sri Lanka is small in size with only 65,610 km2 of land, its significant variation in climate, topography and soil properties has given rise to a striking variety of forest types, which provide habitats for a wide diversity of faunal and floral species. Fifteen floristic regions have been recognized within the country, and these diverse habitats have given rise to a corresponding wide range of natural vegetations including, forests [eg. Tropical wet evergreen forests (lowland rain forests), Tropical moist semi-evergreen forests, Tropical dry mixed evergreen forests, Tropical thorn forests (scrublands), Savannahs, Riverine forests, Tropical lower montane forests & Tropical montane or cloud forests]; grasslands [eg. Wet montane grasslands (wet patanas), Dry montane grasslands (dry patanas), Lowland grasslands (Damana and Talawa), Wet villu grasslands]; inland wetlands [eg. Flood plains, Swamps, Streams and rivers, Seasonal ponds] and coastal & marine habitats [eg. Mangroves, Salt marshes, Sand dunes and beaches, Mudflats, Sea grass beds, Lagoons and estuaries, Coral reefs & Coastal seas] etc. The distribution ranges of most of the reptiles correspond to these particular vegetation types.

  • Sinharaja
  • Motane Cloud Forest
  • Horton Plains
  • Bundala
  • Rivers and Pools
  • Kithalawewa
  • Wasgomuwa
  • Paddy Fields
  • Negambo
  • Pigeon Island

Sri Lankan Reptiles

It is well known that Sri Lanka is a country rich in biological diversity. In fact, Sri Lanka is one of the eight ‘Hottest Hotspots’ out of the 25 Biodiversity Hotspots of international significance and is ranked among the highest in Asia, in terms of ‘biodiversity per unit area.

The island is a mega-hotspot of reptile fauna and harbors a rich composition of tetrapod and serpentoid reptilia, including (as at August 2010) 208 described species with 116 endemic species out of which 37 species are geographical relicts. A further 15 taxa are endemic at subspecies level.

Table 1: A comparison of the tetrapod reptile families in Sri Lanka.

Family Total species Endemic species Endemic subspecies
Gekkonidae (Geckos) 42 31 03
Agamidae (Agamas/ Dragons) 18 15 00
Scincidae (Skinks) 31 24 01
Lacertidae (Snake-eye Lizards) 02 00 02
Chameleonidae (Chameleons) 01 00 00
Varanidae (Monitor Lizards) 02 00 00
Crocodilidae (Crocodiles) 02 00 00
Bataguridae (Hard-shelled Terrapins) 01 00 01
Chelonidae (Hard-shelled Sea Turtles) 04 00 00
Dermochelidae (Leatherback Turtle) 01 00 00
Testudinidae (Toirtoises) 01 00 00
Trionychidae (Soft-shelled Terrapins) 01 00 00
Emydidae (Pond Terrapins) 01 00 00
Total 107 70 07

Table 2: A comparison of the snake families in Sri Lanka.

Family Total species Endemic species Endemic subspecies
Acrochordidae (Wart Snakes) 01 00 00
Typhlopidae (Blind Snakes) 10 08 00
Uropeltidae (Shield-tail Snakes) 15 14 01
Cylindrophiidae (Pipe Snakes) 01 01 00
Pythonidae (Pythons) 01 00 00
Boidae (Boas) 01 00 01
Colubridae (Colubrids) 30 09 04
Elapidae (Cobras, Kraits etc.) 05 02 01
Viperidae (Vipers & Pitvipers) 07 04 01
Elapidae: Hydrophiinae (Sea Snakes) 14 00 00
Elapidae: Laticaudinae (Sea Kraits) 01 00 00
Homalopsidae (Mud Snakes) 03 00 00
Natricidae (Natricids) 12 08 01
Total 101 46 08