The zoologists also showed that spiders kill many times more insects in forests and grasslands than in other habitats.
"These 40 years of gathering experience - spending thousands of hours dealing with spider prey capture rates and prey selection - was needed to be able to write this paper on the global annual prey kill of the spiders", he said in an email. Large tropical spiders occasionally prey on small vertebrates (frogs, lizards, snakes, fish, birds, and bats) or feed on plants.
Meanwhile, humans consume a mere 400 million tons in meat and fish.
A gargantuan figure at least equivalent to the quantities of meat and fish consumed each year by humans (400 million tons), according to data from the Food and Agriculture Organization of the United Nations ( FAO ).
Using data from 65 previous studies, Nyffeler and Birkhofer first estimated how many spiders are now to be found in seven biomes on the planet.
The researchers estimate that there's probably around 25 million metric tons of spiders in the world.
But if you're now worrying that the world might be inherited by spiders, remember that in turn, they are a source of prey as well.More news: Trump's 2005 Tax Returns Published
'Spiders thus make an essential contribution to maintaining the ecological balance of nature'.
Spiders are found everywhere from the Arctic to the most arid of deserts, in caves, on ocean shores, sand dunes and flood plains, the study authors said.
The stunning numbers comes from a study conducted by scientists from the University of Basel in Switzerland and Lund University in Sweden.
With the new findings, it will help future researchers to calculate how spiders eating (and being eaten) contribute to the global food chain, while also shining the spotlight on how necessary these eight-legged critters really are.
More than 8,000 species of birds, other predators and parasites feed exclusively on spiders, said the researchers.
"We hope that these estimates and their significant magnitude raise public awareness and increase the level of appreciation for the important global role of spiders in terrestrial food webs", stated the study, which appeared in the European journal The Science of Nature.