Big trees and blue whales are easily spotted when searching for the Earth’s biggest living things – but not all of our planet’s giants are so obvious. Expanses of connected fungi or coral can also claim the crown of world’s largest life form, and single-celled animals can reach surprising sizes. Caroline Morley
Biggest plant
Giant sequoia ()
Height: 50 to 85 metres
Diameter: 6 to 8 metres
Big trees are not just spectacular sights – they also lock away carbon and create unique biological worlds. In addition to being Earth’s biggest tree, the giant sequoia takes the title of biggest plant.
(Image: WestEnd61/Rex Features)
Biggest animal
Blue whale ()
Length: 30 metres
Weight: 180 tonnes
Blue whale calves are born after a 12-month pregnancy and weigh about 2.7 tonnes at birth. While nursing on their mother’s fat-rich milk (about 400 litres per day), calves fatten up by about 90 kilograms a day. By the time they are weaned, calves may weigh 21 tonnes.
Not surprisingly, then, blue whales are super-efficient feeders. Despite these startling stats, though, they are not the largest organisms on Earth.
(Image: Hiroya Minakuchi/Minden Pictures/Getty)
Biggest organism
Honey mushroom ()
Age: 2400 years
Area: 8.8 square kilometres
A main contender for title of largest organism is a parasitic fungus – Armillaria solidipes.
A single specimen of this fungus spanning 8.8 kilometres2 was found in the Malheur National Forest in Oregon, betrayed by an area of dying trees. The fungus’s black root filaments spread underground, killing the trees in its path.
It’s not all bad news, though – the golden brown mushrooms are edible, except when collected from hemlock.
(Image: Imagebroker/FLPA)
Biggest bacterium
Sulphur pearl of Namibia ()
Length: 750 micrometres
From the biggest of the biggest, we go to the biggest of the smallest. Bacteria are not known for their size, but the sulphur pearl of Namibia is large enough to be seen by the naked eye and has a volume about 3 million times the average bug.
It was discovered in sediment on the sea floor off the coast of Namibia. The bacteria are full of shiny white globules of sulphur and grow in long lines of single cells, making them look like a string of pearls.
(Image: )
Biggest single-celled organism
Sea pearl ()
Diameter: 5.1 centimetres
Known as the sea pearl or sailor’s eyeball, this hollow, water-filled green blob shines like glass underwater. It’s found in virtually every ocean in the world, and tends to cling to coral rubble.
Although it’s a single-celled organism, the sea pearl has multiple nuclei.
(Image: Tobias Bernhard/Oxford Scientific/Getty)
Biggest superorganism
Great Barrier Reef
Area: 20,055 square kilometres
What constitutes an organism? Should we consider a hive of bees, each with its own function, as a single entity? If so, where could this line of thinking take us? With humans and their gut flora sometimes given as an example of a superorganism, it would seem the individuals do not even need to be related.
A leading contender for the planet’s biggest superorganism is Australia’s Great Barrier Reef. It’s the world’s largest structure of living organisms, covering 20,055 kilometres2.
(Image: Eye Ubiquitous/Rex Features)
![Astronomers have long known that understanding how star clusters come to be is key to unlocking other secrets of galactic evolution. Stars form in clusters, created when clouds of gas collapse under gravity. As more and more stars are born in a collapsing cloud, strong stellar winds, harsh ultraviolet radiation and the supernova explosions of massive stars eventually disperse the cloud, and their light can bear down on other star-forming regions in the galaxy. This process is called stellar feedback, and it means that most of the gas in a galaxy never gets used for star formation. Researching how star clusters develop can answer questions about star formation at a galactic scale. Now, the state of the art has been further developed with both Hubble and Webb working together to provide a broad-spectrum view of thousands of young star clusters. An international team of astronomers has pored over images of four nearby galaxies from the FEAST observing programme (#1783), trying to solve this mystery. Their results show that it is the most massive star clusters that clear away their gaseous shroud the fastest, and begin lighting their galaxy the earliest. The team identified nearly 9000 star clusters in the four galaxies in different evolutionary stages: young clusters just starting to emerge from their natal clouds of gas, clusters that had partially dispersed the gas (both from Webb images), and fully unobstructed clusters visible in optical light (found in Hubble images). With Webb???s ability to peer inside the gas clouds, they were able to then estimate the mass and age of each cluster from its light spectrum. This image shows a section of one of the spiral arms of Messier 51 (M51), one of the four galaxies studied in this work, as seen by Webb???s Near-Infrared Camera (NIRCam). The thick clumps of star-forming gas are shown here in red and orange, representing infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Within these gas complexes, each tens or hundreds of light years across, Webb reveals the dense, extremely bright clusters of massive stars that have just recently formed. The countless stars strewn across the arm of the galaxy, many of which would be invisible to our eyes behind layers of dust, are also laid bare in infrared light. [Image description: A large, long portion of one of the spiral arms in galaxy M51. Red-orange, clumpy filaments of gas and dust that stretch in a chain from left to right comprise the arm. Shining cyan bubbles light up parts of the gas clouds from within, and gaps expose bright star clusters in these bubbles as glowing white dots. The whole image is dotted with small stars. A faint blue glow around the arm colours the otherwise dark background.]](https://images.newscientist.com/wp-content/uploads/2026/05/13114322/SEI_296271016.jpg)
