Russell's viper

Identification

Russell’s viper is a stout snake with a broad, flat head much wider than its neck. The head is covered in small, rough (keeled) scales, the nostrils are large and the pupils are vertical. There is no pit between the nostril and the eye¹. The body is light brown with three lengthwise rows of large brown spots, each ringed with black and sometimes edged in white. The middle row can join up into a chain-like stripe^1,2. The belly is whitish or yellowish¹.

Adults over 1.2 m are not unusual, but snakes over 1.5 m are rare; the longest specimens Wall reported measured about 1.68 m².

Distribution

This species lives in Pakistan, India, Nepal, Sri Lanka and Bangladesh, and may also occur in Bhutan¹. It is described as possibly the most common dangerously venomous snake in southern Asia¹.

Russell’s vipers further east, from Myanmar into South-East Asia, were once treated as a subspecies. They are now a separate species, the eastern Russell’s viper (Daboia siamensis), so D. russelii refers only to the South Asian populations^1,3.

Habitat

Russell’s viper prefers open, sunny country such as grassland, scrub and farmland, and it avoids dense forest². During the day it usually lies coiled quietly among grass or other low plants². It lives from the plains into the hills, and in Sri Lanka it is found up to about 1,500 m above sea level¹.

Across South and South-East Asia, most snakebites happen to farm workers and are on the feet and ankles, so care is needed when walking through fields, especially after dark³.

Behaviour

Russell’s viper is mainly active at night. By day it is usually found resting in grass, but after dark it moves about, crosses roads and sometimes enters houses². It is slow-moving and often holds its ground rather than fleeing².

When disturbed it heaves its body in and out and gives a deep, loud hiss, made by blowing air out through its large nostrils². WHO guidelines list it among the more “irritable” snakes that strike readily when threatened, so it should always be given plenty of space³.

Diet

Small mammals, especially rats and mice, make up most of this viper’s diet². Early records also include squirrels, shrews, small birds, lizards and frogs². In captivity, young Russell’s vipers have been seen attacking and eating one another².

Reproduction

Russell’s viper gives birth to live young rather than laying eggs^1,2. The Reptile Database gives litters of 5–50 young¹, and Wall noted that broods of 30–40 were frequent, with up to 63 recorded². Newborn snakes are about 20–28 cm long². They are venomous from birth and can kill small prey within seconds².

Venom and medical significance

Together with the Indian cobra, common krait and saw-scaled viper, it is one of the “big four” species traditionally considered the most dangerous in India^3,4. In Sri Lanka it causes about 30% of snakebites³.

A typical serious bite causes swelling at the bite site together with problems in blood clotting. This can lead to dangerous bleeding, shock and acute kidney injury³. In Sri Lanka and India bites can also cause muscle weakness and muscle damage³. Some survivors later develop long-term hormone problems from damage to the pituitary gland³. A bite is a medical emergency: go to a hospital immediately.

Conservation

The IUCN Red List classes Russell’s viper as Least Concern (assessed 2021)⁵. It is widespread and often common¹.

In India it is protected under Schedule I of the Wild Life (Protection) Act, as revised in 2022⁶. India’s population is also listed in Appendix III of CITES, which covers international trade in wildlife⁶.

Similar species

The Indian rock python (Python molurus) also has large, dark-edged blotches on a pale body, so the two can look alike^1,2. The viper has strongly keeled, rough-looking scales in 27–33 rows, while the python has smooth scales in more than 60 rows^1,2. The viper’s spots are neat, dark-ringed ovals in three rows; the python has larger, squarish blotches and a spear-shaped mark on the head^1,2. Pythons also have small pits on the front lip scales, which the viper lacks^1,2.

These differences are not a safe basis for handling any snake. Russell’s viper is dangerously venomous³, so treat every unidentified snake as dangerous.

In captivity

Russell’s vipers have long been kept in Indian museums and zoos, where many feed well, although some refuse food². Antivenoms are made using Russell’s viper venom, and venom from one region may not match bites from another³. In India the species is protected under Schedule I of the Wild Life (Protection) Act⁶. It is a dangerously venomous snake and should never be kept as a pet or handled by anyone without training.