INDIA’S ‘BIG FOUR’

These species pose the biggest threat to humans in the Indian subcontinent

1 Russell’s viper

This snake is responsible for the majority of snakebite deaths in India. In Sri Lanka, this nocturnal viper likes to rest in paddy fields, causing high mortality among paddy farmers during harvest time. The snake’s venom can lead to acute kidney failure, severe bleeding and multiorgan damage.

2 Saw-scaled viper

Rather than the stereotypical ‘hissing’ sound attributed to snakes, this viper starts ‘sizzling’ by rubbing together special serrated scales when threatened. A bite can cause localised swelling and pain, followed by potential haemorrhage and ultimately acute kidney failure. There are nine types of antivenom for this snake.

3 Indian cobra

Often seen with snake charmers, these deadly cobras – also known as the spectacled cobra, Asian cobra or binocellate cobra – can vary in colour and pattern. Typically, this snake will bite at night, with the venom released causing internal bleeding. The solitary predators are often found in tree hollows and within rocky terrain.

4 Common krait

The common krait usually tries to avoid light and humans. When this snake does attack people, it releases extremely potent venom with presynaptic neurotoxins. This paralyses muscles, controlled by the central nervous system. Many victims can survive because the venom is unable to stop the heart directly.

Venom can be extracted safely for study

Russell’s vipers can grow to be two metres long

The saw-scaled viper is the smallest of the ‘Big Four’

The Indian cobra spreads the hood around its head to appear more threatening

The common krait can be active during both the day and night