Largest Organisms
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50 free Largest Organisms trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Ask what the world's largest organism is and the answer depends on how you measure. By weight, by height, by area covered or by sheer length, a different record holder steps forward each time, and several of them are not animals at all. Some of the largest organisms on Earth look like whole forests, or lie hidden underground and underwater. This quiz covers the record holders across the tree of life: the heaviest and tallest animals on land and in the water, the biggest birds, reptiles, fish and invertebrates, towering trees and outsized flowers, fruits and seeds, sprawling fungi, and single cells big enough to see without a microscope. A final stretch visits the prehistoric giants known only from fossils. It suits nature lovers, pub quiz fans, students and teachers, and anyone who enjoys a good superlative. Every answer comes with a short explanation, so you will finish knowing what holds each record and why the title is sometimes disputed.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which marine mammal, a krill-eating giant, is the largest animal known to have ever existed?
Blue whale
Blue whale hearts set records too: the heart of one stranded animal weighed 180 kg, the largest known in any animal.
Q 02Pando, a Utah forest of about 47,000 stems sharing one root system, is a clone of which tree?
Quaking aspen
Quaking aspen sends up new stems from its roots, and Pando, at an estimated 6,000 tonnes, is the heaviest tree known.
Q 03The largest known fungal colony, a honey mushroom spanning about 3.5 square miles, lies beneath which US state?
Oregon
Oregon's Malheur National Forest holds the colony nicknamed the humongous fungus, which may weigh as much as 35,000 tons.
Q 04Which giant sequoia in California, named after a Civil War commander, is the largest living single-stem tree by volume?
General Sherman
General Sherman was once renamed in honor of Karl Marx by a socialist logging colony, and got its old name back when the colony was disbanded in 1892.
Q 05Hyperion, the tallest known living tree at more than 115 metres, belongs to which species?
Coast redwood
Coast redwood Hyperion was found in 2006 by two naturalists, and it took the height record from another California redwood, the Stratosphere Giant.
Q 06A single seagrass plant cloned across about 180 km of seabed, the largest plant known, grows off which country?
Australia
Australia is home to the giant, a ribbon weed that needed at least 4,500 years of creeping across the seafloor to become the largest known organism by area.
Q 07Which slow, filter-feeding giant is the largest fish alive today, with one individual reliably recorded at 18.8 metres?
Whale shark
Whale shark mouths can hold over 300 rows of tiny teeth, yet the fish feeds by filtering plankton, fish eggs and small schooling fish from the water.
Q 08Which deep-sea animal of Antarctic waters is the heaviest living invertebrate and has the largest eyes ever documented?
Colossal squid
Colossal squid eyes measure about 27 to 30 cm across, and the heaviest specimen, a 495 kg female, was hauled up by a New Zealand fishing boat in 2007.
Q 09Which cold-water jelly, one of the largest known, trails sticky tentacles that can stretch 30 metres or more?
Lion's mane jellyfish
Lion's mane jellyfish carry around 1,200 stinging tentacles, which they use to capture and pull in fish and smaller jellies.
Q 10Which rainforest plant of Southeast Asia produces the largest individual flower on Earth, about a metre across?
Rafflesia
Rafflesia lives hidden inside a host vine and shows itself only to bloom; the widest flower ever measured was 1.14 metres across.
Q 11Which is the largest and heaviest living land animal, whose biggest measured bull stood nearly 4 metres at the shoulder?
African bush elephant
African bush elephant ears can grow as large as 2 metres by 1.5 metres, and they double as radiators that help shed body heat.
Q 12Which flightless bird, the tallest and heaviest alive, has the largest eyes of any land vertebrate?
Common ostrich
Common ostrich hens also lay the largest eggs of any living bird, in a communal nest that the male scrapes out of the ground.
Q 13Which bird has the longest wingspan of any living bird, up to 3.7 metres, and can glide for hours without flapping?
Wandering albatross
Q 21The titan arum of Sumatra, whose flower spike can stand over 3 metres tall, is notorious for smelling of what?
Rotting flesh
Rotting flesh is the scent that lures the carrion beetles and flesh flies that pollinate it, and the spike heats up to about 37 °C to help carry the smell.
Q 22Which marine arthropod has the greatest leg span of any, reaching about 3.7 metres from claw to claw?
Japanese spider crab
Japanese spider crab claws were singled out in the first scientific description of the species for the serious injuries they can cause.
Q 23Which shallow-water mollusc, the largest living bivalve, gets most of its food from algae living in its tissues?
Giant clam
Wandering albatross flights ring Antarctica, making it one of the most far-ranging birds as well as the widest-winged.
Q 14Which reptile, the largest alive, has the strongest bite ever recorded for an animal in a laboratory?
Saltwater crocodile
Saltwater crocodile jaws closed with 16,414 newtons of force in the test, beating a record previously held by an American alligator.
Q 15Which Indonesian reptile is the largest living lizard, with males reaching 3 metres long and 150 kg?
Komodo dragon
Komodo dragon bites do not depend on filthy, bacteria-laden mouths, as legend has it; the slashing bite delivers venom and saliva that stops blood clotting.
Q 16Which mostly aquatic snake is the heaviest in the world, with females growing far larger than the males?
Green anaconda
Green anaconda females average about 4.6 metres against roughly 3 metres for males, though the reticulated python holds the title of longest snake.
Q 17Which sea turtle is the largest of all living turtles and can weigh 500 kilograms?
Leatherback
Leatherback turtles are among the deepest-diving marine animals, and their flexible carapace helps them withstand the pressure of dives to 1,200 metres.
Q 18Which South American animal, a close relative of the guinea pig, is the largest living rodent?
Capybara
Capybara share a quirk with guinea pigs: they cannot make vitamin C, and captive animals without supplements have developed signs of scurvy.
Q 19Which animal is the largest living land carnivore by body mass, with adult males weighing 300 to 800 kg?
Polar bear
Polar bear skin is black beneath the pale fur and absorbs heat, while a layer of fat up to 10 cm thick sits underneath it.
Q 20Which deep-diving marine mammal is the largest toothed predator on Earth and has the largest brain of any animal?
Sperm whale
Sperm whale clicks are the loudest sounds made by any animal, and its brain is more than five times heavier than a human's.
Giant clam shells open by day so the algae in the mantle can catch the sun; the largest known specimen was 137 cm long and weighed about 250 kg alive.
Q 24Which invertebrate of northern European seas, barely a centimetre wide, has been reported at lengths of up to 55 metres?
Bootlace worm
Bootlace worm specimens typically measure 5 to 15 metres, and the 55-metre reports may describe animals stretched beyond their usual length.
Q 25The heaviest spider in the world, a South American giant with a body up to 13 cm long, belongs to which group?
Tarantulas
Tarantulas of this species are known as birdeaters, a name that goes back to an 18th-century engraving of one eating a hummingbird.
Q 26Queen Alexandra's birdwing, found only in one province of Papua New Guinea, is the largest species of which insect?
Butterfly
Butterfly females of this species can span more than 25 cm, dwarfing the males, and the whole population lives in about 100 square km of rainforest.
Q 27Which biblical name is carried by the largest living frog, a 3-kilogram amphibian of Cameroon's waterfalls?
Goliath
Goliath frogs can slightly exceed 80 cm with their legs outstretched, and the heaviest one reliably weighed came in at 3.3 kg.
Q 28Which filter-feeding fish, with a body disc up to 7 metres across, has the largest brain of any fish?
Giant manta ray
Giant manta ray brains weigh up to 200 g, and the animal itself, the largest ray in the world, can weigh around 3,000 kg.
Q 29Which tailless, flattened giant, one of the largest bony fish, can produce up to 300 million eggs at a time?
Ocean sunfish
Ocean sunfish were long misidentified as the heaviest bony fish, a title that belongs to a closely related species, Mola alexandrini.
Q 30Which fruit-eating bats include the largest bat species in the world, with wingspans reaching up to 1.7 metres?
Flying foxes
Flying foxes find their food by sight and smell, not echolocation, and the heaviest of them, the great flying fox, weighs up to 1.6 kg.