If you’re looking to impress your friends at trivia night, here’s a fun fact: the largest living organism on Earth isn’t the blue whale or a giant tree—it’s a fungus!
You might think of fungi as those little mushrooms that pop up in the woods. But most of a fungus is hidden underground, much like an iceberg. The mushrooms we see are just the fruiting bodies, similar to apples on a tree. The real bulk of the fungus lies beneath the soil in a network of tiny, thread-like structures called mycelium. Some fungi even have specialized roots called rhizomorphs that help them grow. While the average mushroom is only a few inches tall, the biggest fungus is massive!
This giant fungus covers about 3.7 square miles. That’s roughly the footprint of two Gatwick Airports combined or three Central Parks. To visualize it another way, it equals the surface area of about 18,500 adult blue whales!
This massive organism is known as the honey fungus. It was first named Armillaria solidipes by mycologist Charles Horton Peck in 1900. In 1970, Henri Romagnesi renamed it Armillaria ostoyae. Both names are used today, but honey fungus works just fine.
Mostly found in North America, honey fungus feeds on trees and produces mushrooms with sweet, brown caps. Its mycelium can glow in the dark, creating a soft green light known as “foxfire.”
Researchers discovered this giant fungus in 1998 after many trees in Oregon’s Malheur National Forest mysteriously died. A genetic study revealed that one clonal fungus was responsible, not multiple organisms.
In 2017, scientists found out that the honey fungus has a unique set of genes. These genes help it grow its rhizomorphs deep into the soil to find wood, then break it down with special enzymes. Estimates suggest that this colossal organism could be between 2,400 and 8,650 years old. So, the honey fungus is not just the largest living thing—it’s also one of the oldest!
This fascinating fungus shows us how interconnected life can be, reminding us that the biggest things might not always be what we think. If you’re curious to learn more about this amazing organism, you can check out Nature.
