Distributed range & status
These snakes are widely spreaded in the plains & mid hills of Sri Lanka, up to 1500m but they are more common in the dry zonal forests & grasslands, human habitats. Within its range it can be very common in some areas, but scarce in others. They are also found from Pakistan, India, China, Java, Bangladesh, Colombia, Nepal, Thailand, Taiwan, and East Indonesia.

Scales

The crown of the head is covered with irregular, strongly fragmented scales. Eyes are surrounded by 10-15 circumorbital scales. There are two pairs of chin shields, the front pair of which are notably enlarged. The dorsal scales are strongly keeled & rough. Only the lower row is smooth. Mid-body, the dorsal scales number 27-33.

Characteristics
The body is stout, the cross-section of which is rounded to cylindrical. It has a more slender built body than most other vipers. The head is dorso-ventrally flattened, triangular and distinct from the neck. The snout is blunt, rounded and raised. The nostrils are large. The eyes are large & consist of an eclipsed pupil. Very thin & short tail is present. It’s about 14% of the total body length. The supranasal sacs are known to act as the heat-sensitive organs.

Colour
The pattern consists of a deep yellow, tan or brown ground color, with three series of dark brown spots that run the length of its body. Each of these spots has a black ring around it, the outer border of which is intensified with a rim of white or yellow. The dorsal spots, (23-30) may grow together, while the side spots may break apart. The head has a pair of distinct dark patches, one on each temple, together with a pinkish, salmon or brownish V or X pattern that forms an apex towards the snout. The eyes are flecked with yellow or gold. Behind the eye, there is a dark streak, outlined in white, pink or buff. The venter is white, whitish, yellowish or pinkish, often with an irregular scattering of dark spots.

Venom
These snakes are highly venomous having a solenoglyphous venom system. There are many types of venoms so multisystemic manifestation may occur. Haemotoxins, neurotoxins, nephrotoxins, & myotoxins are some that are included. The amount of venom produced by individual specimens is considerable. Reported venom yields for adult specimens range from 130-250 mg to 150-250 mg. For 13 juveniles with an average length of 79 cm, the average venom yield was 8-79 mg (mean 45 mg). For most humans a lethal dose is 40-70 mg.

The victim usually start showing symptoms begin with pain at the site of the bite, immediately followed by swelling of the affected extremity. Bleeding occurs, especially from the gums, and sputum may show signs of blood within 20 minutes post-bite. There is a drop in blood pressure and the heart rate falls. Blistering occurs at the site of the bite, developing along the affected limb in severe cases. Necrosis is usually superficial and limited to the muscles near the bite, but may be severe in extreme cases. Vomiting and facial swelling occurs in about one-third of all cases.

Severe pain may last for 2-4 weeks. Locally, it may persist depending on the level of tissue damage. Often, local swelling peaks within 48-72 hours, involving both the affected limb and the trunk. If swelling up to the trunk occurs within 1-2 hours, 98% of the bites show massive envenomation. Discoloration may occur throughout the swollen area as red blood cells and plasma leak into muscle tissue. Death from respiratory, kidney failure or cardiac failure may occur 1 to 14 days post-bite or even later.

If the correct medication is not given death occurs of the victim. Sri Lanka use the polyvalent antivenin which is prepared in India to treat bites In India.

Dentition
The two maxillary bones support at least two and at the most five or six pairs of fangs at a time: the first are active and the rest replacements. The fangs attain a length of 16 mm in the average specimen. When handled, specimens have been known to use their long, curved fangs to bite right through their lower jaw and into the thumb of the person holding them.

Behavior
They are terrestrial & more active at night but also seen in day time. During colder whether. These snakes are known to be more active in the day time. It is not restricted to any particular habitat, but prefers dense forests. The snake is mostly found in open, grassy or bushy areas, but may also be found in scrub jungles, on forested plantations and farmland. The main reason they are attracted to human habitation is the presence of rodents. As a result, those working in fields in these areas are most at risk of being bitten. They are most common in plains, coastal lowlands and hills of suitable habitat. Generally not found at altitude, but has been reported as far up as 2300-3000 m. humid environments, such as marshes, swamps and rain forests, are avoided.

Adults are reported to be persistently slow and sluggish unless pushed beyond a certain limit, after which they becomes fierce and aggressive. Juveniles, on the other hand, are generally more active and will bite with minimal provocation. When threatened they form a series of S-loops, raise the first third of the body and produce a hiss that is supposedly louder than that of any other snake. When striking from this position, they can exert so much force that even a large individual can lift most of its body off the ground in the process. These are difficult snakes to handle due to them being strong and agile and react violently to being picked up. The bite may be a snap, or, they may hang on for many seconds. Their presence can also be detected by the characteristic smell they release which is similar to flower fragrance of Madhuca longifolia.

Breeding
This species is ovoviviparous. Mating generally occurs early in the year, although gravid females may be found at any time. The minimum length for a gravid female is about 100 cm. It seems that sexual maturity is achieved in 2-3 years. The gestation period is more than six months. Young are produced from May to November, or mostly in June and July. It is a prolific breeder. Litters of 20-40 are common, although there may be fewer offspring and as little as one. The reported maximum is 65 in a single litter. In one case, it took a specimen nearly 4.5 hours to produce 11 young.

Growth
At birth, juveniles are 215-260 mm in length. This snake grows to a maximum length of 1660 mm 800-1300mm. Ditmars (1937) reported the following dimensions for a "fair sized adult specimen"
Total length 4 ft., 1 inch 124 cm
Length of tail 7 inches 18 cm
Girth 6 inches 15 cm
Width of head 2 inches 5 cm
Length of head 2 inches 5 cm

Food
It feeds primarily on rodents. However, they will eat just about anything, including rats, mice shrews, squirrels, domestic cats, land crabs, scorpions and other arthropods, birds. Juveniles are crepuscular, feeding on lizards and foraging actively. Especially the Juveniles are known to be cannibalism.

Identification
D. russelii is known as a very successful species and has such a fearful reputation within its natural environment. Superficially, the rough-scaled Sand boa, Gongylophis conicus, mimics Daboia russelii appearance. It has a color pattern that often looks a lot like that of D. russelii, even though it is completely harmless. So they are easily mistaken as Daboia russelii & most often killed.