Puff adders control rodents naturally, protecting crops. They could be key to sustainable agriculture.
One of Africa’s most widespread snakes may turn out to be an agricultural hero in disguise
A study led by the University of the Witwatersrand in Johannesburg, South Africa, found that puff adders (Bitis arietans) are remarkably effective at suppressing rodent populations that threaten crop production across the continent.
These snakes are capable of increasing their food intake more than twelvefold during rodent population booms, a rate that surpasses many mammalian predators. This feeding flexibility positions them as a natural and highly efficient solution to widespread rodent pest problems.
“Puff adders are essentially nature’s perfect rodent control system,” says Professor Graham Alexander, who conducted the study. “Their ability to dramatically increase consumption during rodent outbreaks makes them invaluable allies for farmers facing potential crop devastation.”
Feeding efficiency and crop protection
The findings, published in Scientific Reports, show that a single puff adder can consume as many as 10 rodents in one feeding session. Within just a week, the snake is able to hunt again, offering continuous pest control at no cost to farmers. Because rodent outbreaks often coincide with high rainfall years and cause millions in agricultural losses, conserving puff adder populations could greatly reduce crop damage while limiting the need for chemical pesticides.
Key advantages over mammalian predators
Offering a compelling case for snake conservation, the research identifies several key advantages of puff adders as natural pest controllers:
- Puff adders can raise their food intake far beyond basic needs, outperforming mammalian predators such as weasels and lynx.
- After periods of heavy feeding, they are able to survive for up to two years without food, staying in the ecosystem as “on-call” rodent controllers.
- They shift their hunting behavior to focus on rodents when populations start to rise.
- They can act quickly to stop rodent numbers from escalating to plague levels.
“What’s particularly valuable about puff adders is their natural abundance in many African habitats,” says Alexander. “While an individual Puff Adder consumes much less than a fox or mongoose, their higher population abundance creates a formidable collective impact on rodent numbers.”
Measuring ingestion and reframing snakes
In conducting this research, Alexander used a new measure called “factorial scope of ingestion,” which measures how much a predator can increase its food intake above normal maintenance levels, as well as the impact that a large population of snakes might have on prey animals. By increasing their prey intake by 12 times their normal food needs during rodent blooms, a large population of snakes can have a considerable impact on keeping possible pest outbursts under control. This study challenges the traditional view of snakes as agricultural pests and reframes them as beneficial partners for sustainable farming.
“These findings demonstrate that puff adder population management should be an essential component of integrated pest management strategies,” says Alexander. “By protecting these natural controllers, we can harness their remarkable abilities to support both ecosystem health and agricultural productivity across Africa. This also highlights the need to have snakes included in conservation management plans.”
Reference: “Factorial scope of ingestion and the potential functional response of puff adders (Bitis arietans) to high prey abundance” by Graham J. Alexander, 13 May 2025, Scientific Reports.
DOI: 10.1038/s41598-025-99550-3
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