Make us your home page
Instagram

Today’s top headlines delivered to you daily.

(View our Privacy Policy)

Creepy! Spiders could theoretically eat every human on Earth in one year

The total biomass of all adult humans on Earth is estimated to be 287 million tons. Even if you tack on another 70 million-ish tons to account for the weight of kids, it's still not equal to the total amount of food eaten by spiders in a given year, exceeding the total weight of humanity. In other words, spiders could eat all of us and still be hungry. [Times]

The total biomass of all adult humans on Earth is estimated to be 287 million tons. Even if you tack on another 70 million-ish tons to account for the weight of kids, it's still not equal to the total amount of food eaten by spiders in a given year, exceeding the total weight of humanity. In other words, spiders could eat all of us and still be hungry. [Times]

Spiders are quite literally all around us. A recent entomological survey of North Carolina homes turned up spiders in 100 percent of them, including 68 percent of bathrooms and more than three-quarters of bedrooms. There's a good chance at least one spider is staring at you right now, sizing you up from a darkened corner of the room, eight eyes glistening in the shadows.

Spiders mostly eat insects, although some of the larger species have been known to snack on lizards, birds and even small mammals. Given their abundance and the voraciousness of their appetites, two European biologists recently wondered: If you were to tally up all the food eaten by the world's entire spider population in a single year, how much would it be?

Martin Nyffeler and Klaus Birkhofer published their estimate in the journal the Science of Nature earlier this month, and the number they arrived at is frankly shocking: The world's spiders consume somewhere between 400 million and 800 million tons of prey in any given year. That means that spiders eat at least as much meat as all 7 billion humans on the planet combined, who the authors note consume about 400 million tons of meat and fish each year.

Or, for a slightly more disturbing comparison: The total biomass of all adult humans on Earth is estimated to be 287 million tons. Even if you tack on another 70 million-ish tons to account for the weight of kids, it's still not equal to the total amount of food eaten by spiders in a given year, exceeding the total weight of humanity.

In other words, spiders could eat all of us and still be hungry.

To arrive at this number Nyffler and Birkhofer did a lot of sophisticated estimation based on existing research into A) how many spiders live in a square meter of land for all the main habitat types on Earth, and B) the average amount of food consumed by spiders of different sizes in a given year.

These numbers yielded some interesting facts on their own. For instance, one study estimated that global average spider density stands at about 131 spiders per square meter. Some habitats, like deserts and tundra, are home to fewer spiders. On the other hand, spider densities of 1,000 or more individuals per square meter have been observed under certain "favorable" conditions — because Nyffler and Birkhofer don't define what "favorable" means in this context, I'm going to assume it refers to dark, dusty places like the area under my bed.

If you gathered up all the spiders on the planet and placed them on a very large scale, together they'd weigh about 25 million tons, according to Nyffler and Birkhofer. For comparison, the Titanic weighed about 52,000 tons. The mass of every spider on Earth today, in other words, is equivalent to 478 Titanics.

Spider biologists have also generally found that spiders consume about 10 percent of their body weight in food per day. That's equivalent to a 200-pound man eating 20 pounds of meat each day.

Conversely, it would take about 2,000 pounds of spiders to consume a 200-pound man in one day.

In the end, spiders' voracity actually works out to mankind's benefit. Since they primarily feast on bugs, their hunger means fewer pests in the garden, fewer mosquitoes in the yard and fewer flies in the house.

Creepy! Spiders could theoretically eat every human on Earth in one year 03/28/17 [Last modified: Tuesday, March 28, 2017 1:30pm]
Photo reprints | Article reprints

© 2017 Tampa Bay Times

    

Join the discussion: Click to view comments, add yours

Loading...
  1. Jameis Winston's hardest lesson: He can't always save the day

    Bucs

    TAMPA — Ever wonder what in the world goes through Jameis Winston's mind when he tries to fit the ball in a keyhole as he is being dragged to the turf like he was during Thursday night's 12-8 preseason win over the Jaguars?

    JACKSONVILLE, FL - AUGUST 17:  Jameis Winston #3 of the Tampa Bay Buccaneers attempts a pass during a preseason game against the Jacksonville Jaguars at EverBank Field on August 17, 2017 in Jacksonville, Florida.  (Photo by Sam Greenwood/Getty Images) 700069805
  2. Despite pain, woman in court faces ex-boyfriend who lit her on fire

    Criminal

    PORT RICHEY

    Sheron Pasco sat in the wheelchair as her mother pushed it toward the man in the orange jail suit.

    Sheron Pasco, 39, right, along with her mother Tranda Webb, 62, pose for a photograph Wednesday, at their home in Port Richey. Pasco's former boyfriend John Riggins doused Pasco with gasoline and set her on fire after an argument last year.. CHRIS URSO   |   Times

  3. Florida starter under center still under wraps

    College

    GAINESVILLE — With two weeks before Florida opens its season against Michigan, the Gators' three-way quarterback battle remains wide open.

    Luke Del Rio, right, is in the mix to start against Michigan in the season opener … as is Malik Zaire and Feleipe Franks.
  4. A sports rout on Wall Street

    Retail

    NEW YORK — Sporting goods retailers can't shake their losing streak.

  5. Rick Kriseman picks Floribbean restaurant for Manhattan Casino

    Local Government

    ST. PETERSBURG— Mayor Rick Kriseman has chosen a controversial restaurant concept to occupy the Manhattan Casino, saying he made a decision 11 days before the mayoral primary because he didn't want politics to get in the way of progress in struggling Midtown.

    Former Tampa Bay Buccaneers wide receiver Vincent Jackson speaks during a Friday press conference announcing that the Callaloo Group will open a Floribbean restraurant in the historic Manhattan Casino in St. Petersburg's Midtown neighborhood. Some residents were upset with Mayor Rick Kriseman's choice, saying it will speed up gentrification of the area. [EVE EDELHEIT   |   Times]