Echis carinatus

Saw-scaled Viper is the only Echis species found in India and member of famous Big Four. This is also the smallest Viperidae member with an average size of 30cm only. Indian Saw Scaled Viper's population ends eastwards in Odisha and West Bengal states with eastern-most boundary of the genus Echis. It can be identified by carefully checking very dry looking body covered with rough scales, light color rounded patches on top which are surrounded by two wavy lines from head to posterior body. In deserts and semi-deserts of India this is perhaps the most common venomous snake and so the most important medically significant reptile for deserts and semi-deserts.

Midbody there is 25-39 rows of dorsal scales that are keeled scales with apical pits; on the flanks, these have serrated keels. There are 143-189 ventral scales that are rounded and cover the full width of the belly. The subcaudals are undivided and number 21-52, and the anal scale is single.

DIAGNOSTIC CHARACTERES

Head:
10-12 supralabials (4th largest); 10-15 small size scales around eyes (excluding supraocular); 3-4 scales between nasal and eyes; 8-12 scales between supraoculars.

Dorsal:
Highly keeled scales in 25-29: 27-37: 21-27 rows; obliquely arranged scales in 4-7 rows (these are responsible for its famous saw like sound due to mutual rubbing of side dorsals).

Ventral:
132-185; anal divided or undivided.

SubCaudal:
23-39; undivided.

REPRODUCTION

Ovoviviparous, mating season starts with male combats. Reproduction ovoviviparous, female directly gives birth to 6-8 young individuals during summer to monsoon months. 

SIZE

New born- 8cm
Average length- 30cm
Maximum length- 80cm. (Depends on geographical areas, South Indian population is known for smaller size)

MORPHOLOGY

Dorsal:

Body short, robust and stout. Highly keeled pointed scales of dry appearance found in all over the dorsal body. Body color ranges from light to dark brown, gray, brick red or reddish-brown. Light color spots of light yellow or very light brown margined by dark color found in whole dorsal surface; these spots may be more symmetric on mid body; usually guarded and connected by two undulating lines from both sides (head to posterior body).

Ventral:

Belly color white with dark brown or blackish spots in all ventral scales; these spots become larger and more prominent on side ventrals. Subcaudal scales undivided.

Head:

Head triangular with small shaped keeled scale; clearly broader than neck. One Arrow or cruciform shaped or somewhat plus shaped mark always exists on the top of the head which may have long or short arms. Large eyes with vertical pupil. Two long foldable fangs present on the fore side of the mouth in all life stages.

Tail:

Short tail with a pointed tip, covered with keeled scales; typical dorsal patterns may be absent or faint.

Looks close to juvenile of Common Sand Boa (Eryx conicus) and Common Cat Snake (Boiga trigonata)

BEHAVIOUR

Saw-scaled Viper is a nocturnal species which remains active from late evening to late nights for foraging and other life activities. Can be seen at day time while basking on habitat. Activity usually terrestrial but climbs on scrub vegetation for basking. Locomotion slow and use side winding motion for creeping faster. Behaviour very alert, aggressive and quick to respond. This is one of the fastest striking snakes and takes much less than 1 second time to bite and back to its original place. On provocation it makes a specific coil to keep the head on front and middle of the coil which is followed by mutual rubbing of oblique scales present on flank. This rubbing produces fascinating sound of "working of saw". Strikes very fast when enemy approaches to its attacking range and delivers small but very potent amount of venom even by scratching only. 

Feeds on small rodents, geckos, other snakes, insects including scorpions.

VENOMOSITY

Venomous

GENERAL HABITAT

Found both in moderate elevation and plains. Distributed in variety of forests including deserts, semi-deserts, rainforest, scrub forest, mixed, dry and moist deciduous forest, grassland etc. Habitat includes dry open lands, agricultural field, scrubs, rocky terrain, open plains etc. Hides in mounds, holes, piles, caves, cracks, dense leaf litters, rocks etc.