How Effective Are Spiders at Eating Insects?

Spiders are known to eat approximately 10 percent of their body weight every day. That is equal to a 200-pound (91-kg) man wolfing down 20 pounds (9.1 kg) of meat each day, which would be awfully hard to do. In a 2017 study published in the journal Science of Nature, scientists Martin Nyffeler and Klaus Birkhofer estimated that the world's spiders gobble up between 400 million and 800 million tons of prey every year -- equal to the weight of the meat and fish eaten annually by the planet's 7 billion humans.

Itsy-bitsy spiders, big appetites:

  • Spiders eat insects almost exclusively, although some of the larger arachnid species sometimes dine on lizards, birds, and even small mammals.
  • There are more than 45,000 spider species in the world, and Nyffler and Birkhofer estimate that, weighed together, the total spider population would tip the scales at 25 million tons.
  • Hungry spiders are a benefit, keeping garden pests and mosquitoes in check. Their appetite is on par with the world's whales, which collectively eat an estimated 280 million to 500 million tons of prey a year.
More Info: New Scientist

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