Snakes on a train: How king cobras are spreading across India thanks to world’s busiest railway network

King cobras are spreading to different parts of India by hitching rides on some of the country’s busiest railway networks, a new study has found.

The Western Ghats king cobra (Ophiophagus kaalinga), a vulnerable species in India, has been documented spreading to many parts of India’s western tourist state of Goa via trains.

Normally, the species is most likely to be found in the interior part of Goa, in its forested areas and near rivers and streams, away from the state’s famous coastal zones.

However, new research assessing decades of records revealed railway sites in some of the unlikeliest areas where the cobras, deemed the world’s longest venomous snakes, were found.

These areas were far less suitable for the species than their natural habitat, scientists say.

The findings suggest India’s railway networks, which are the busiest in the world by passenger volume, are contributing to King Cobra migration and putting the snakes into unsuitable habitats.

Analysing snake rescue data and verified local reports documented from 2002 to 2024, researchers found 47 localities for O kaalinga in Goa, with 18 in the northern part of the state, and 29 in the south.

Five of these king cobra records were near busy railway corridors, scientists say.

“It is noteworthy that the five king cobra records that fall along busy railway corridors had the lowest predicted probability, as predicted by our model,” they wrote in the study published in the journal Biotropica.

"With the increased global availability of low-cost smartphones and social media in recent years, the number of reports of snakes on and around trains in India has increased,” researchers wrote.

Three of these incidents were recorded in a 30-day period, with “many more emerging on social media”, scientists say.

“Combined with recent reports of snakes on trains in India and of O. kaalinga in a rail yard, entirely unsuitable reptile habitats, we propose the hypothesis that snakes, king cobras included, may inadvertently expand their ranges by accidental transport on trains,” researchers concluded.

They suspect the availability of prey in the form of rodents and other snakes aboard India’s goods carrier trains, as well as “shelter and serendipity”, could be driving this migration.

"Our findings suggest a different, more passive mechanism: railways may act not just as corridors for active movement, but as high-speed conduits,” scientists wrote.

“The potential for railways to inadvertently connect populations across otherwise unsuitable habitats represents a novel and under-appreciated aspect of human-wildlife interaction," they added.