Rat Snake ( Ptyas mucosa Linnaeus, 1758 )

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Scientific Name: 
Ptyas mucosa (Linnaeus, 1758)
Regional Names: 
ಕೇರೆ ಹಾವು (kEre hAvu)
Dhaman, Ghoda-Pachad, Ashadhia
Oriental Rat Snake
Yellowish-brown form. Madhya Pradesh
All over the India including North-east and Andaman Islands.
Venom Type: 
Characteristics for identification: 

Very long body with dark color 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 color 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.


New born- 32-47cm.
Average length- 210cm (7ft).
Maximum length- 350cm (11ft & 6inch)

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 color of the dorsal. These black colored patterns become net-Like on tail side and more prominent than rest of dorsal. Dorsal color varies from jet black (Central India and parts of North-East), greenish black, range of brown, yellow etc. Sometimes black colored specimens lack any patterns.

Ventral -
Belly color also depends on color of dorsal; from pale yellow or white mixed with green, brown, gray, yellow etc. sometimes dark color 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 color border present on upper lip and underside scales. Large eyes have rounded pupil. Tongue color purplish-black with darker color 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.

8 supralabial; 4th & 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.
Both smooth and keeled scales in 17/18/19: 16/17: 14 rows.
190-213; angulated laterally; anal divided.
Sub Caudal: 
100-146; paired; Hemipenis extends to the 10th-12th caudal plate, not forked.
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 behavior few times), while dry during monsoon.
Natural History: 
Rat Snake is a diurnal species which shows both arboreal and terrestrial activity depending upon foraging and resting needs. Behavior 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. 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 upto 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.
Feeds on a variety of prey mostly on rodents and toads; also feeds upon birds, small mammals, other snakes, all kind of lizards, eggs etc.
Threats includes killing due to misidentification with venomous species like King Cobra, other Cobra species. This is one the most intentionally threatened snake in its range due to its prone activity in and around humans and large size. In many parts of its range it is exploited for skin and edible use. Snake charmers use this species in snake charming because of its large size and harmless to display nature.
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