Gaboon viper habitat will increase by 250% by 2070. Photo: Phil Sandlin

Climate change is likely to trigger large-scale migrations of venomous snakes into new areas and unprepared countries, according to research published in the journal Lancet Planetary Health. A research group predicts that Nepal, Niger, Namibia, China and Myanmar will welcome the most venomous snake species from neighboring countries as the climate warms, Guardian reported May 3. Low-income countries in South and Southeast Asia, as well as parts of Africa, will be vulnerable to a rise in snakebite cases.

The study modelled the geographic distribution of 209 venomous snake species that can cause human emergencies to understand where different snake species will find favourable climatic conditions by 2070. While most venomous snake species will experience a range contraction due to the loss of tropical and subtropical ecosystems, the habitat of some species such as the West African gaboine adder will increase by 250%. The distribution of the European asp and the desert horned adder are also projected to more than double by 2070.

However, some snake species, including the endemic African horned snake and the American snub-nosed snake, will lose more than 70% of their habitat. As more and more land is converted to farmland and livestock, the natural habitats that snakes depend on are destroyed and fragmented, according to study co-author Pablo Ariel Martinez of the Sergipe Federation at the University of California and Talita F. Amado at the Biodiversity Research Center in Leipzig, Germany. The research results show that some venomous snake species can adapt to farmland and even thrive in areas where crops or livestock provide food sources, such as rats.

The World Health Organization (WHO) estimates that between 1.8 and 2.7 million people are bitten by venomous snakes each year, resulting in 138,000 deaths and at least 400,000 cases of amputation and permanent disability. The WHO ranked snakebite envenoming as the leading neglected tropical disease in 2017.

“Snake species will shift their distribution with climate change. The concern is that they will bite more people if warm temperatures, wet weather events and flooding lead to loss of people and snakes become more common,” said Anna Pintor, a scientist specializing in neglected tropical diseases at WHO. “We need to better understand how this affects where and how many people are bitten so we can be prepared.”