This species is found in Thailand, but not within Bangkok itself
English name: Variable Reed Snake
Scientific name: Calamaria lumbricoidea
Thai name: งูพงอ้อหลากลาย (Ngu Plong Ao Lag Lai)
Description: To 64 cm. A small snake with an indistinct head. Dark brown or black above with an iridescent sheen, rarely with narrow light lines. Young snakes have a pink head and white or yellow bands but both turn black in adulthood. Tail is rounded. Belly is white to bright yellow to orange, usually with distinct black bands.
Relevant scale counts: 13 midbody rows of smooth scales. 5 supralabials. First pair of infralabials are not in contact and the mental touches the front pair of chin shields. Males 144-196 ventrals and females 137-229, males 17-27 subcaudals and females 13-21.
Similar Species: Pink-headed Reed Snake has a grayish-white belly without black bands, and 1st pair of infralabials in contact so that mental is separate from the 1st pair of chin shields.
Collared Reed Snake is a lighter brown with a single band near its neck and two bands near the tail, and with small black granules dirtying the yellow belly.
Short-tailed Reed Snake has brownish-black belly with cream center without black bars.
Range: Thailand, Malaysia, Singapore, Indonesia, and the southern islands of the Philippines.
Habitat: Typically found in forests up to 1676 m elevation, but can also be seen under cover in wooded city parks and gardens.
Place in the ecosystem: Feeds on earthworms and other soft-bodied invertebrates, and at times small lizards and frogs. Would be eaten by larger snakes.
Danger to humans: Is not at all dangerous to humans.
Conservation status and threats: The IUCN Red List reports that it is known from relatively few locations and may be threatened by deforestation. However, I have recently seen many records of them across Thailand. It is possible that they are rarely seen due to their fossorial nature, or that they are misidentified for other snakes.
Interesting facts: Juveniles of this species are far more colorful and conspicuous than the adults. Why would such vulnerable youngsters be colored like this? 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.
The DNA of Singapore: Calamaria lumbricoidea
Ecology Asia: Variable Reed Snake
Calamaria, a genus of small fossorial reed snakes
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