Scales and sustainability: puff adders’ farming superpower

Many fear snakes, but puff adders, one of Africa’s most common venomous snakes, could be doing something extraordinary for the continent’s farmers.

According to a study by the University of Witwatersrand in Johannesburg, puff adders can play a surprising role in helping farmers protect crops without having to reach for poison. During rodent outbreaks, puff adders (Bitis arietans) can dramatically increase their food intake, helping to keep fast-breeding pests like rats in check.

“Puff adders are essentially nature’s perfect rodent control system,” explains Professor Graham Alexander, who led the study. “Their ability to boost their feeding when rodents are abundant makes them incredibly useful allies to farmers.”

The study shows that a single puff adder can eat up to 10 rodents in one sitting and then be ready for another meal just a week later. During high rainfall periods, when rodent numbers explode, this makes a significant difference.

To assess this, researchers used the concept, "factorial scope of ingestion," to show how puff adders can boost their food intake up to 12 times during rodent outbreaks. The findings highlight their potential to curb pest surges and reframe snakes as valuable allies in sustainable agriculture. Compared to predators like foxes or mongooses, puff adders proved far more capable during prey population booms.

After a period of heavy feeding, puff adders can go up to two years without eating, lying around quietly in the background, ready to step in again when needed. Their numbers across the continent also mean their collective impact is much bigger than most realise.

“This changes how we think about snakes on farmland,” says Alexander. “They’re not just something to avoid, they’re part of the solution.”

Rodent outbreaks during high rainfall years cause the loss of millions in crop damage annually. For farmers facing revenue devouring pests, and looking for sustainable alternatives to chemicals, the answer might just be nature itself.

We first published this article in the third edition of ThisWildEarth. See our publications here

A specimen from Grahamstown. Credit: Luke Kemp

Credit: Graham Alexander

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