The Russell’s viper, Daboia russelii (Photo credit: Davidvraju, used under Creative Commons license CC BY-SA 4.0).

Urban Vipers 10: The Russell’s Viper in Rathnapuri, India

Posted onAugust 19, 2024byOjibway Massasauga|News and Events, Ojibway Prairie Reptile Recovery, Urban Vipers

Snakebites from the Russell’s viper are very common in India and can result in permanent disability or even death. Is long distance translocation a viable alternative to extermination as a way to keep village residents safe while protecting the Russell’s viper population?

WHAT IS THE RUSSELL’S VIPER?

The Russell’s viper (Daboia russelii) is a large venomous snake found throughout the Indian subcontinent. These snakes are yellow to brownish in colour with three rows of dark oval-shaped spots running the length of their backs. They can grow to about 1.2 metres in length and are thick-bodied. They are active at night, hunting rodents, small reptiles, and small invertebrates, but they have also been found to bask and hunt during the day.

Russell’s vipers are abundant in India and are not designated at-risk. However, they are protected under Schedule II of the 1972 Wildlife (Protection) Act, which prohibits trade and hunting unless they are diseased or injured beyond recovery, or if they pose a threat to human life. Considered one of India’s “big four” medically-important snakes, the Russell’s viper is responsible for the greatest number of snakebite mortalities in the country. These snakes are regularly encountered by people, likely due to their ability to survive in a variety of habitats, including human-dominated landscapes. Rural areas on the outskirts of towns and cities are often disproportionately affected by snakebite, which usually occurs on the hands and legs of people working close to the ground, such as harvesting crops.

HOW IS HUMAN-SNAKE CONFLICT MANAGED IN THE RATHNAPURI AREA?

Snakes found close to homes or work sites are removed and translocated elsewhere by wildlife conservationists to keep people safe and also to rescue snakes from the immediate danger of being killed by villagers. These types of snake removals are called “mitigation” translocations. When Russell’s vipers are removed from towns and villages to prevent human-snake conflict, they are often translocated long distances and released at a site outside of their home range. For example, one snake rescuer from a city neighbouring Rathnapuri translocated snakes 15–60 km from their capture sites. In contrast, these fairly sedentary animals naturally make movements of much shorter distances—only 100 m per move, on average.

After being translocated far distances, it’s possible that Russell’s vipers experience lower-than-normal survival rates as they move around in search of familiar territory; Snakes are generally at elevated risk of threats such as predators or roadkill during dispersal. It’s also possible that translocated Russell’s vipers are exposed to greater stress levels or rates of disease than their counterparts. Due to the frequency of snake translocations in India, rescuers sometimes keep snakes in captivity for days and transport multiple snakes in the same bin to a release site, conditions which are stressful and that could facilitate disease transmission. Given these uncertainties, a Master’s student at Bangor University, Rhiannon Williams, set out in 2019 to study the effect of long-distance translocations on Russell’s vipers in and around the village of Rathnapuri, and to determine whether those effects posed a threat the viper population.

Hunsur, India, the closest city to the village of Rathnapuri, both located in the southwestern region of the Indian state of Karnataka. Snakebites are more common in rural villages where there is more naturalized habitat than in dense urban areas (Photo credit: Tar-ba-gan, used under Creative Commons licence CC BY-SA 4.0)

WHERE WERE THE TRANSLOCATED RUSSELL’S VIPERS RELEASED?

The translocation study took place at the site of the Gerry Martin Project (GMP), situated just outside of Rathnapuri, a rural Indian village in the state of Karnataka. The GMP was based at a 0.8 ha (2-acre) property consisting of farmland and a lake, with edge habitat composed mostly of scrubland and grassland. This project was created to manage human-wildlife conflict in Rathnapuri and surrounding villages, with a focus on wildlife research, education, and snake translocations.

Rhiannon Williams conducted her study on 11 male Russell’s vipers that were rescued from neighbouring villages, implanted with radiotransmitters, and translocated to the GMP property, which was far outside their home ranges. The GMP was deemed suitable for translocation because it had natural habitat, suitable refugia for snakes, and minimal human activity. The translocated snakes were tracked daily over eight months in 2019 (Apr to Nov), and their movement patterns were compared to those of 7 male “resident” vipers from the area. Those resident snakes were also radiotracked but were not translocated.

Aerial view of the Gerry Martin Project, adjacent to the lake in the centre of the map, and the surrounding human-dominated landscape. The village of Rathnapuri is in the centre-right of the map (Photo credit: Williams 2021).

WHAT HAPPENED TO THE TRANSLOCATED RUSSELL’S VIPERS?

Overall, a higher mortality rate was recorded in the translocated snakes compared to the resident snakes; 7 of the 11 translocated snakes (64%) died during the study compared to only 2 of the 7 resident snakes (29%). The cause of death for all snakes ranged from being killed by humans (44%), predation (33%), and parasites or unknown causes (22%). The movement patterns of most resident and translocated snakes were compared, including average daily movement, average distance per movement, and movement frequency. Four of the translocated snakes, however, died too early on in the study for their movement patterns to be quantified.

Average daily movement and distance per movement did not significantly differ between the translocated and resident snakes. Individuals from both groups stayed within a small home range and moved similar distances during each movement. However, translocated snakes moved less frequently than resident snakes. One possible explanation for this difference was that translocated snakes were in relatively poor body condition. For example, two translocated snakes were confirmed to have been infected by parasites. A second possible explanation for reduced movement in the translocated snakes is that their usual mating behaviour was suppressed. During the breeding season, male snakes will often travel long distances to search for and mate with females. The translocated snakes, however, did not move as would be expected during this time, and none were observed mating. In contrast, the average home range of the resident snakes during this period was twice as large as that of the translocated snakes.

CAN PEOPLE LIVING IN THE RATHNAPURI REGION COEXIST WITH RUSSELL’S VIPERS?

Mitigation translocations of venomous snakes are common in India and will no doubt continue due to the high risk of potentially dangerous interactions between people and snakes. This study on Russell’s Viper translocations showed some promising results because movement distances of translocated individuals were similar to those of resident snakes. Unfortunately, translocated snakes were more likely to have died than resident snakes, an outcome very similar to what was found in other studies where snakes were translocated long distances (See Urban Vipers 6: Dugites in Perth, Australia). Furthermore, the fact that some translocated vipers had poor body condition or did not exhibit normal mating behaviour may be an indication of additional negative effects of long distance translocations.

Snakes translocated in tropical regions, such as India, likely face a different set of limiting factors than snakes translocated in temperate zones. Although Russell’s Vipers are not exposed to chilling winter temperatures, they are killed by a variety of predators throughout the year, including humans. Predation clearly plays an important role in the survival of translocated Russell’s Vipers considering the majority of snakes in this study were predated or killed. Ironically, people were the main predator, despite the fact that snakes were translocated to save them from being killed in the first place. Thus, long-distance translocation in the scenario studied is probably not the best solution for promoting coexistence between vipers and people. Human-snake conflict with Russell’s vipers may be better managed by only translocating snakes short distances (Urban Vipers 6: Dugites in Perth, Australia), or by implementing preventative strategies such as increased public awareness, supplying agricultural workers with protective footware, and improving access to antivenom (see efforts by the Madras Crocodile Bank Trust Centre for Herpetology). Further research into the effectiveness of such alternatives may result in improved outcomes that better allow humans and snakes to live side by side.

“Conservation should not be treated as a cause or an act of altruism. It should become a way of life.”

Gerry Martin 2022Herpetologist and founder of the Gerry Martin Project

Authorship note: This blog post was originally drafted by Remo Boscarino-Gaetano, and revised and edited by Natasha Sawatzky, Kathleen Woodhouse, Alexis Simeoni, and Jonathan Choquette.

REFERENCES

Glaudas, X. 2021. Natural history of a highly medically important snake, Russell’s viper (Daboia russelii), in a human-dominated Indian rural landscape. Journal of Herpetology. 55(2): 151-159.

Ghosh, S., Mukhopadhyay, P. and Chatterjee, T. 2016. Management of snake bite in India. The Journal of the Association of Physicians of India. 64: 209-218.

Williams, R.C. 2021. Translocation of a medically important snake: Russell’s Vipers (Daboia russelii) in rural India (Masters Thesis, Bangor University). Available from Bangor University Research Portal.

WPC appreciates funding support provided by the Ontario Ministry of Environment, Conservation and Parks’ Species at Risk Stewardship Program for WPC’s Ojibway Reptile Recovery Program.