This Is Horrifying: Spiders Eat Twice As Much Flesh As Humans Every Year

But don’t freak out: The 400 to 800 million tons of meat that eight-legged insects put away includes pests like mosquitoes and flies. Pick your battles, and try not to think about it too much.

This Is Horrifying: Spiders Eat Twice As Much Flesh As Humans Every Year
[Photo: Flickr user Steve Bittinger]

You might think–given that our carnivorous tendencies and systematized farming of meat and fish have endangered the Earth’s ecosystem–that humans are the most prolific flesh consumers on the planet. Not so. In fact, it’s spiders, who manage to eat as much as double the amount of meat humans put away each year.


Humans eat around 400 million tons of meat and fish each year; a new study finds that in the same time frame, the “global spider community” collectively kills 400 to 800 million tons of prey, in the form of free-range insects. If that doesn’t creep you out, then consider this: They do most of their hunting and killing at night, while we lay unconscious and vulnerable in our beds.

The study, completed by researchers in Switzerland, Germany, and Sweden, used data from 65 previous studies to come up with the new figures. The combine census data on the number of spiders per square meter in various biomes with field estimates of spider populations. The researchers then overlayed this data of the number of spiders in the world with data on how much food a spider needs to survive, along with their observed predatory habits.

[Photo: Flickr user Christian Gloor]

The researchers found that 25 million tons of spiders eat 400 to 800 million tons of insect flesh every year. Horrifyingly, that predatory volume falls within the same order of magnitude as that inflicted by whales, who eat 280 to 500 million tons of fish each year; it far surpasses the contribution of seabirds, who manage a paltry 70 million tons of fish and seafood annually. This finding cements spiders at the top of the list of the most prolific predators on the planet. Try not to think about that the next time you wake up to see a new web spun on the ceiling above your bed.

But this is not actually a reason to freak out: 95% of spiders’ annual kill occurs in forests and grasslands, far away from homes and other human habitats. Farms, for instance, where annual crops are grown and harvested, account for just 2% of spider “prey kill.”

And spiders, lest you forget, are just another part of the food chain–they’re not invincible. Between 8,000 and 10,000 other animals–parasites included–feed exclusively on spiders, and 3,000 to 5,000 bird species also eat more than their fair share of spiders. Spider deaths due to being crushed by rolled-up newspapers or the heels of hastily grabbed shoes are not included in the study.

Perhaps this information will change the way you think about our eight-legged friends. Far from meaning you harm, these lovely creatures could actually be protecting you with their prolific predatory tendencies: Among those 800 million tons of spider prey are countless mosquitoes that would have sucked your blood, and flies that would have camped out on the food left in your kitchen. But apologies to the arachnophobes out there: This research is probably not doing much to quell your fears.

About the author

Previously found writing at, Cult of Mac and Straight No filter.