A photo of a giant mushroom – large enough to eclipse a group of people – allegedly shows the largest living thing in the world. It is real or just another internet hoax?
The story is real but the photo is fake.
The Real Story
As first reported in August 2000, the world’s “biggest living thing” is the honey mushroom (Armillaria ostoyae) of Oregon. It covers 2200 acres and is estimated to be over 2400 years old. It was discovered in the late 1990’s using aerial photos and through DNA testing cultures from 112 dying trees.
A paragraph from the story linked above has been circulating online for years, which is an accurate description of the “world’s largest thing.” The shared story, however, often includes a fake photo of a single, giant mushroom that completely misrepresents the story and the honey mushroom. The story included with the photo reads:
Oregon’s monster mushroom is world’s biggest living thing
The largest living organism ever found has been discovered in an ancient American forest. The Armillaria ostoyae, popularly known as the honey mushroom, started from a single spore too small to see without a microscope. It has been spreading its black shoestring filaments, called rhizomorphs, through the forest for an estimated 2,400 years, killing trees as it grows.
The Fake Photo
The caption fails to mention that the fungus is not a single, massive growth, but actually covers many square miles of land. The giant mushroom depicted in the photo is a digital creation, and does not show the honey mushroom of Oregon.
The first step we took in debunking this photo was to look closely for obvious signs of manipulation. The person in the red shirt, for example, appears to be using binoculars, which wouldn’t be necessary for an object only about 20-feet high. The edges of the mushroom indicate that a photo of a mushroom was cut out and enlarged (see below). It would also stand to reason that if such a massive mushroom did exist, there would be more photos of it. Such an amazing sight would have been well-documented by scientists and journalists, yet the photo above is the only image in existence of this large mushroom.
According to the website by Tom Volk, Professor of Biology at University of Wisconsin-La Crosse, “The largest fungal fruiting bodies known are… only about 300lbs.”
There are several signs of digital manipulation of the image. Take, for example, how the edges of the stem change when background changes to the forest behind it. The edge changes from a smooth, slightly blurry line to a very sharp edge. This indicates that the image of the mushroom was likely cut out and placed there. See the enlargement below.
True source: “Boletus photoshopus”
Although we felt our “edge analysis” was enough to debunk the hoax, we decided to dig a little deeper and ask around to see if any “mushroom experts” could tell us anything else about the image. We first contacted Professor Volk to see if he had any insights, and he was familiar with the popular image. His response was:
We then sent an email in January 2013 to Tom Bruns at UC Berkeley, who responded immediately. His quirky response included the subject of Boletus photoshopus with a single statement:
Pictured in its natural habitat – the digital photo. – Tom Bruns
In other words, the “natural habitat” of the mushroom in the image is in a digital photo. We love the name he gave the mushroom in the picture: Boletus photoshopus.
The giant mushroom pictured above is a digital creation and does not depict the world’s “largest living thing.” The image originated from the lab of Tom Bruns from UC Berkeley, apparently as a joke. Over two years since we first investigated this graphic, it continues to circulate heavily online.
We’d like to thank Thomas Volk and Tom Bruns for helping us debunk the image once and for all. Who knew that fungi experts could be so cool?
Updated April 27, 2015
Originally published January 2013