This species is found in Thailand, but not within Bangkok itself
English name: Pink-headed Reed Snake (aka: “Red-headed Reed Snake”, “White-headed Reed Snake”)
Scientific name: Calamaria schlegli
Thai name: งูพงอ้อหัวแดง (Ngu Pong-ao Hua Daeng)
Description: To 49 cm. A small dark gray, brown, or almost black snake with an iridescent sheen. Head can be red, pink, yellow, or white, sometimes partially or fully discolored by the dorsal coloration. Tail is blunt. Belly is cream or white with a grayish tint. In some specimens there is yellow between the dorsal and ventral coloration.
Relevant scale counts: 13 midbody rows of smooth scales. 5 supralabials. First pair of infralabials are in contact behind the mental, which is
separated from the front pair of chin shields. Males 129-161 ventrals and females 136-180, males 25-44 subcaudals and females 19-37.
Similar Species: Variable Reed Snake often has bright yellow to orange belly, sometimes with black bands, and only juveniles have colored heads (always read rather than yellow/white). Its infralabials are separated and the mental is in contact with the front pair of chin shields.
Range: Extreme southern Thailand, Malaysia, Singapore, and Indonesia
Habitat: Forests up to 1000m, as well as agricultural land and occasionally venturing into parks and gardens.
Place in the ecosystem: Feeds on earthworms and other soft-bodied invertebrates as well as small frogs. Would be eaten by larger snakes.
Danger to humans: Is not at all dangerous to humans though it closely resembles venomous kraits and coral snakes. Never touch a snake unless you are absolutely certain of the ID!
Conservation status and threats: This is a common and widespread species with no known threats.
Interesting facts: Why would a fossorial snake have such a brightly colored head? It is possible that they are mimicking the Blue Coral Snake or the Red-headed Krait, both extremely venomous species with similar red heads. It is also possible that the colors play on the general tendency of predators to be wary/surprised when they suddenly see brightly colored prey.
Thai National Parks: Pink-headed Reed Snake
IUCN: Red-headed Reed Snake
Ecology Asia: Pink-headed Reed Snake
Identification and a new record from Penang Island of the rare redbellied reed snake
A New Species of the Genus Calamaria from the Highlands of the Langbian Plateau, Southern Vietnam
A Field Guide to the Reptiles of Southeast Asia