Snakes of Sri Lanka - 12

Snakes of Sri Lanka - 12

By Jayasri Jayakody

Common Ratsnake (Ptyas mucosus) Gerandiya

A large snake with a colouration that varies from black to dark brown occasionally yellow, the Common Ratsnake has a pointed snout and large eyes and nostrils. Its common name is derived from its heavy inclination to prey upon rats.

A very active often diurnal snake it is usually harmless and makes every possible attempt to avoid human confrontation. However the Mr. Hyde of the Common Ratsnake is clearly revealed once cornered. First it hisses in attempt to deter its adversary. If this fails it strikes repeatedly often drawing blood. If captured its frequency of striking is increased. This snake never does well in captivity and often injures itself by striking against glass walls or wire mesh of the vivarium. Therefore it is advisable to never attempt to corner or capture this snake unless you are ready for a rough treatment.

As its name suggests its staple diet consists of rats. (However Burmese specimens seem to avoid rats for some reason) It also preys upon frogs, squirrels, birds, bandicoots, lizards and other snakes. It will even resort to cannibalism if the conditions are right. This snake is known to seek out its prey using its highly developed sense of smell, track it down and capture it after pursuit. It is also known to storm into crevices where rats are known to inhabit and capture its prey by surprise. The prey is quickly swallowed whole often while still alive. Frogs and rats especially can often be heard calling from within its stomach before succumbing due to its digestive fluids. There have even been cases were frogs have been recovered intact from killed individuals.
This snake however often ends up being preyed upon by other species. Mongooses, eagles, kraits and cobras frequently prey upon this snake.

The Common Ratsnake is oviparous. Breeding patterns very considerably according to climate and little has been studied about them in local regions. The male and female tend to remain together for a while after mating has taken place before going their own separate ways. The clutch varies from 9 to 14. The period of gestation and incubation tend to vary considerably as with the size of the eggs which are often 50mm in length.

The hatchlings are usually around 40cm long and very active. They grow very quickly and reach sexual maturity at around 1.5 m in around three years. The average length of this snake is around1.8m with 2.4m being the maximum length though outsized specimens up to 3.3m (sic) are also occasionally reported. This snake sloughs on a monthly basis. This non-venomous snake can be identified at a distance by the characteristic dark brown dorsal and yellowish brown ventral colouration that sets it apart from other Sri Lankan snakes. Its eye is also proportionatly larger than most other snakes. Distributed in the Indian Subcontinent, Afganistan, Southern China, Indo-China, Malay peninsular, Caspian region and Java Sri Lankans naturally know how abundant this snake is. It can be found throughout the island in sheer abundance up to altitudes of over 1800m. It often ventures into human dwellings where it feeds on rodent pests. Unfortunately many Sri Lankans are inclined to chase it away by using kerosene oil (paraffin) regardless of its effectiveness as a rat controller. Jerdon's Polyodont (Sibynophis subpunctatus) Dathigomaraya Little is known about the behaviour of this snake. It is highly active, diurnal and terrestrial feeding mainly on lizards and frogs. Very little has been recorded about its reproductive behaviour. This snake is oviparous and the clutch size is usually between 2 and 5. The eggs measure 19mmx7mm. The females of this non-venomous snake are capable of reproducing once 325mm long. The maximum length for this species is 450mm.A rare snake the Jerdon’s Polyodont is found in India and Sri Lanka, along the west coast of Sri Lanka ranging from Puttalam to Kalutara. It can be found inland as far as Ratnapura but it is absent from the central hills.

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