Ptyas

Rat Snake (Dhaman) is a commonly seen snake which is famous for its fast-crawling speed and much larger size than most of the widely distributed species found in India. Very long body with dark colour patterns on the whole dorsal surface are its general identification features. Apart from these it can be identifies precisely by checking posterior body reticulated with black colour net like markings. Traditionally people differentiate between Cobra and Rat Snake by accepting Rat Snake to be a snake having head broader than neck or neck thinner than mid body.

DIAGNOSTIC CHARACTERS

Head:

8 supralabial; 4th and 5th in contact with eyes; preocular 1; presubocular 1; loreal 1-4 but 3 is most common; postocular 2; temporal 2+2. Maxillary teeth 20 -25.

Dorsal:

Both smooth and keeled scales in 17/18/19: 16/17: 14 rows.

Ventral:

190-213; angulated laterally; anal divided.

Sub Caudal:

100–146; paired; Hemipenis extends to the 10th–12th caudal plate, not forked.

Scales 17:18 or 19:17 or 16: 14 rows. Ventrals 190-213. Anal scale divided. Subcaudals 100-146, paired.

REPRODUCTION

Mating season of Rat Snake begins from winters and extends to start of monsoon. This begins with breeding male combats near water bodies. Combat is done by mutual winding of male bodies to make helix of posterior half and raised forebody where they try to show dominance over each other. After showing dominance and winning, the male performs mating ritual which is done in silent places away from human disturbance. Female lays up to 35 eggs in silent and dark places which are usually in caves, large mounds, between rocks and wood piles. Egg guarding and incubation is done by female till hatching. The period of incubation is around 60-80 days depending upon weather. Most of the new born seen during whole of monsoon and starting of winters. Oviparous.5-14 eggs per clutch.

SIZE

New-born- 32-47cm

Average length: 210cm (7ft) 

Maximum length: 350cm (11ft & 6inch)

MORPHOLOGY

Dorsal:

Body slender with smooth and keeled scales (majority of scales smooth). Keeled scales present on 4-8 topmost rows mostly on the posterior body. Regular black, yellow and white band like markings present on the whole body according to the colour of the dorsal. These black coloured patterns become net-Like on tail side and more prominent than rest of dorsal. Dorsal colour varies from jet black (Central India and parts of North-East), greenish black, range of brown, yellow etc. Sometimes black coloured specimens lack any patterns.

Ventral:

Belly colour also depends on colour of dorsal; from pale yellow or white mixed with green, brown, gray, yellow etc. sometimes dark colour patches exist on the whole belly. Subcaudal scales paired in zig-zag manner.

Head:

Head pointed, not depressed with shiny smooth scales, clearly broader than the neck. Blackish colour border present on upper lip and underside scales. Large eyes have rounded pupil. Tongue colour purplish-black with darker colour on the front side.

Tail:

Long and slender tail typically like other arboreal snakes with a pointed tip. Blackish reticulations present on the whole posterior body. Preocular: 1-2; Postocular: 4; Supralabials: 8 (4th and 5th touches eye); Infralabials: 8-10; Anterior temporals: 2; Posterior temporals: 2; Dorsal scale row formula: 17/18/19: 16/17:14/16. Ventrals: 190-213; Subcaudals: 100-146 (paired). Dorsum wheatish, olive, brown, greyish black. Black mark present over body often prominent at posterior part. Venter white or yellowish white with caudal scales having black edges.

ECOLOGY

Diurnal snake, feeds on frogs, lizards, bats etc.

BEHAVIOUR

Rat Snake is a diurnal species which shows both arboreal and terrestrial activity depending upon foraging and resting needs. Behaviour fast, alert and very quick to respond. On threatening it creeps away from enemy and tries to hide in dark and narrow places like holes, cracks, dense bushes etc. In cornered position it laterally inflates forebody and growls. Can bite on further disturbance. 

Feeds on a variety of prey mostly on rodents and toads; also feeds upon birds, small mammals, other snakes, and all kind of lizards, eggs etc.

VENOMOSITY

Ptyas mucosa, commonly known as the Oriental Rat Snake or Dhaman, is indeed a non-venomous snake. It does not possess venom glands or produce venom.

GENERAL HABITAT 

Wide variety of habitats - Open forests, backyard garden, paddy, grassland, plantation and around human habitations (up to 4000m above msl). Damp grassland, woodland, semi desert, close to human habitation. 

Remain hidden in dark and silent places like rat holes, termite mounds, wood caves, under rocks or any narrow and dark place. Distributed in variety of forests including rainforest, scrub lands, semi-desert, dry, moist and mixed deciduous forests, grasslands, mangroves, wetlands etc. Lives in almost all kinds of habitat due to its tendency to survive in tough conditions; this includes urban areas, dense & open forest, hills & plains, agricultural lands etc. Prefers wet surroundings during summer (shows semi aquatic behaviour few times), while dry during monsoon.