When we think of the biggest animals on Earth, blue whales (Balaenoptera musculus) often come to mind. These massive creatures can weigh over 150 tons, making them heavier than even the largest dinosaurs! But when it comes to the biggest living thing, it depends on how we define “biggest.”
The tallest living organism is a redwood tree (Sequoia sempervirens) known as “Hyperion,” located in California. This tree stands at an incredible 115 meters tall, which is taller than the Statue of Liberty by about 25%! Imagine looking up at something that tall!
Now, let’s talk about the most extensive organism, which is a gigantic fungus in Oregon. This “humongous fungus” covers an amazing 2,385 acres in a national forest. At the base of trees, you might spot clusters of “honey mushrooms” (Armillaria solidipes). These mushrooms are just the visible part of the fungus, like the apples on an apple tree (Malus domestica). The main part of the fungus, called “mycelia,” spreads underground, through the soil, and even into the roots and bark of trees, gathering nutrients to keep growing.
If we consider the heaviest organism, it’s not a giant panda (Ailuropoda melanoleuca) on a Utah plateau—just kidding! It’s actually a single quaking aspen (Populus tremuloides) named “Pando.” Pando weighs over 6,000 tons, which is about the same as forty blue whales! In Fishlake National Forest, you won’t see one giant tree trunk. Instead, you’ll find a forest of normal-sized trees. But genetic testing shows that this forest, covering 106 acres, is actually one giant organism that started from a single seed long ago.
Pando spreads because its roots send up shoots that grow into what look like individual trees. All 47,000 “trees” are part of the same organism. This means the forest does some cool things, like changing from winter to spring all at once and sharing water and nutrients through its huge root system.
When we talk about weight, if we included water, the humongous fungus might weigh more than Pando. But foresters usually measure the dry mass, which is the weight without water. Since fungi are mostly water, Pando is considered heavier in this way. However, over time, some of the underground connections might have broken, so these giants might actually be made up of smaller, but still huge, parts.
Because it takes a lot of testing to confirm which is the “biggest,” both the fungus and the aspen can only claim to be the largest living organisms ever found. Who knows? There might be even bigger organisms hidden underground, just waiting to be discovered!
Imagine you’re a scientist on a mission to find the biggest organisms on Earth. Create a poster that compares the blue whale, Hyperion, the humongous fungus, and Pando. Include their sizes, weights, and interesting facts. Use drawings, photos, or digital images to make your poster visually engaging.
Take a virtual field trip to California’s redwood forests or Oregon’s national forests. Use online resources to explore these environments. Write a short report on what you learned about the habitat and the organisms living there. Share your findings with the class.
Conduct a simple experiment to observe fungi. Collect a small sample of soil or a mushroom from your backyard. Use a magnifying glass or microscope to examine the mycelium. Draw what you see and describe how it might be similar to the humongous fungus in Oregon.
Use an online tree growth simulator to understand how trees like Pando grow. Experiment with different conditions such as sunlight, water, and soil type. Record how these factors affect the growth of your virtual tree and compare it to the real-life growth of Pando.
Participate in a class debate on what should be considered the “biggest” organism. Prepare arguments for different criteria such as height, weight, or area covered. Discuss why each organism might be considered the biggest and vote on which criteria should be used.
Blue whales (*Balaenoptera musculus*) are the largest animals ever to exist on Earth. They can weigh over 150 tons, surpassing even the largest dinosaurs! However, the blue whale is not the biggest living thing. That title depends on how you define “biggest.”
The tallest living organism may be a redwood tree (*Sequoia sempervirens*) nicknamed “Hyperion” in California, which stands at an impressive 115 meters, making it taller than the Statue of Liberty at 93 meters—about 25% taller, in fact. The most extensive organism is a very old “humongous fungus” that spans an astonishing 2,385 acres in a national forest in Oregon. At the base of the trees, clusters of “honey mushrooms” (*Armillaria solidipes*) can be seen; these are the “fruiting bodies” produced by the fungus, which primarily lives out of sight. Imagine if apple trees (*Malus domestica*) grew underground and only the apples were visible—that’s similar to how this fungus operates, spreading its “mycelia” not just through the soil but also through the roots and bark of trees, extracting nutrients to continue its expansion.
If we consider the heaviest organism ever found, that title goes to a giant panda (*Ailuropoda melanoleuca*) living high on a Utah plateau—just kidding! It actually belongs to a single quaking aspen (*Populus tremuloides*) named “Pando,” which weighs over 6,000 tons—equivalent to about forty blue whales. When you visit Fishlake National Forest, you won’t see a giant tree trunk; instead, you’ll find a forest of regular-sized trees. However, genetic testing has revealed that this stand of aspen, covering 106 acres, is actually a single clonal organism that originated from one seed long ago.
This single tree was able to spread extensively because its roots send up shoots that develop into what appear to be individual trees. Since all 47,000 “trees” are part of the same organism, the forest exhibits some unique behaviors; for instance, it transitions simultaneously from winter to spring and utilizes its vast root network to distribute water and nutrients from trees with abundance to those in need.
Speaking of water, if we include water in the weight of these giant organisms, the humongous fungus might actually weigh more than Pando. However, foresters typically focus on the mass produced during growth, known as dry mass. Since fungi are mostly water, Pando takes the lead in this category. Regardless, it’s likely that some of the underground connections, whether roots or mycelia, have been severed over time, meaning these giants are probably composed of smaller, yet still enormous and genetically identical, patches.
Finally, due to the extensive testing required to confirm claims of being the “biggest,” both the fungus and the aspen can only assert that they are the largest living organisms ever found. There may be even larger organisms hidden beneath our feet, just waiting to be discovered!
Organism – A living thing that can grow, reproduce, and respond to its environment. – Example sentence: Every organism in the forest, from the smallest insect to the largest bear, plays a role in the ecosystem.
Fungus – A type of organism that includes molds, yeasts, and mushrooms, which often decompose organic material. – Example sentence: The fungus growing on the fallen log helps break down the wood into nutrients that enrich the soil.
Tree – A large plant with a trunk, branches, and leaves, which provides oxygen and habitat for many organisms. – Example sentence: The tree in our backyard is home to several bird nests and provides shade during the hot summer months.
Aspen – A type of tree known for its smooth, white bark and leaves that tremble in the wind. – Example sentence: The aspen trees in the forest turn a brilliant yellow in the fall, creating a stunning landscape.
Nutrients – Substances that provide the necessary components for growth and health in living organisms. – Example sentence: Plants absorb nutrients from the soil through their roots to grow and produce food.
Roots – The part of a plant that anchors it in the ground and absorbs water and nutrients from the soil. – Example sentence: The roots of the tree spread wide and deep, helping it stay upright during strong winds.
Soil – The top layer of the earth where plants grow, composed of minerals, organic matter, and living organisms. – Example sentence: Rich, fertile soil is essential for growing healthy crops and supporting diverse ecosystems.
Weight – The measure of how heavy something is, often influenced by gravity. – Example sentence: The weight of the fallen tree was too much for the small stream to carry away, creating a natural dam.
California – A state on the west coast of the United States known for its diverse ecosystems, from beaches to forests. – Example sentence: California is home to the giant sequoia trees, some of the largest and oldest living organisms on Earth.
Oregon – A state in the Pacific Northwest region of the United States, known for its lush forests and diverse wildlife. – Example sentence: The forests of Oregon are rich in biodiversity, providing habitat for countless species of plants and animals.
