Largest organisms
The largest organisms now found on Earth can be determined according to various aspects of an organism's size, such as: mass, volume, area, length, height, or even genome size. Some organisms group together to form a superorganism, but such are not classed as single large organisms. The Great Barrier Reef is the world's largest structure composed of living entities, stretching, but contains many organisms of many types of species.
This article lists the largest species for various types of organisms, and mostly considers extant species. The organism sizes listed are frequently considered "outsized" and are not in the normal size range for the respective group.
If considered singular entities, the largest organisms are clonal colonies which can spread over large areas. Pando, a clonal colony of the quaking aspen tree, is widely considered to be the largest such organism by mass. Even if such colonies are excluded, trees retain their dominance of this listing, with the giant sequoia being the most massive tree. In 2006 a huge clonal colony of Posidonia oceanica was discovered south of the island of Ibiza. At across, and estimated at around 100,000 years old, it may be one of the largest and oldest clonal colonies on Earth.
Among animals, the largest species are all marine mammals, specifically whales. The blue whale is believed to be the largest animal to have ever lived. The largest land animal classification is also dominated by mammals, with the African bush elephant being the largest of these.
Plants
The largest single-stem tree by wood volume and mass is the giant sequoia, native to Sierra Nevada and California; it typically grows to a height of and in diameter.The largest organism in the world, according to mass, is the aspen tree whose colonies of clones can grow up to long. The largest such colony is Pando, in the Fishlake National Forest in Utah.
Another form of flowering plant that rivals Pando as the largest organism on earth in breadth, if not mass, is the giant marine plant, Posidonia oceanica, discovered in the Mediterranean near the Balearic Islands, Spain. Its length is about. It may also be the oldest living organism in the world, with an estimated age of 100,000 years.
Green algae
are photosynthetic unicellular and multicellular protists that are related to land plants. The thallus of the unicellular mermaid's wineglass, Acetabularia, can grow to several inches in length. The fronds of the similarly unicellular, and invasive Caulerpa taxifolia can grow up to a foot long.Animals
A member of the infraorder Cetacea, the blue whale, is thought to be the largest animal ever to have lived. The maximum recorded weight was 190 tonnes for a specimen measuring, whereas longer ones, up to, have been recorded but not weighed. It is estimated however that this individual could have a mass of 250 tonnes. The title of the longest non-colonial animal is probably owned by Lion's mane jellyfish.The African bush elephant, of the order Proboscidea, is the largest living land animal. A native of various open habitats in sub-Saharan Africa, this elephant is commonly born weighing about. The largest elephant ever recorded was shot in Angola in 1974. It was a male measuring from trunk to tail and lying on its side in a projected line from the highest point of the shoulder to the base of the forefoot, indicating a standing shoulder height of. This male had a computed weight of 12.25 tonnes.
Heaviest living animals
The heaviest living animals are all cetaceans, and thus also the largest living mammals. Since no scale can accommodate the whole body of a large whale, most whales have been weighed by parts.| Rank | Animal | Average mass | Maximum mass | Average total length |
| 1 | Blue whale | 110 | 190 | 24 |
| 2 | North Pacific right whale | 60 | 120 | 15.5 |
| 3 | Southern right whale | 58 | 110 | 15.25 |
| 4 | Fin whale | 57 | 120 | 19.5 |
| 5 | Bowhead whale | 54.5 | 120 | 15 |
| 6 | North Atlantic right whale | 54 | 110 | 15 |
| 7 | Sperm whale | 31.25 | 57 | 13.25 |
| 8 | Humpback whale | 29 | 48 | 13.5 |
| 9 | Sei whale | 22.5 | 45 | 14.8 |
| 10 | Gray whale | 19.5 | 45 | 13.5 |
showing the size of marine megafauna.
Heaviest terrestrial animals
The following is a list of the heaviest wild land animals, which are all mammals. The African elephant is now listed as two species, the African bush elephant and the African forest elephant, as they are now generally considered to be two separate species.| Rank | Animal | Average mass | Maximum mass | Average total length |
| 1 | African bush elephant | 4.9 | 12.25 | 6 |
| 2 | Asian elephant | 4.15 | 8.15 | 6.8 |
| 3 | African forest elephant | 2.7 | 6.0 | 6.2 |
| 4 | White rhinoceros | 2 | 4.5 | 4.4 |
| 5 | Indian rhinoceros | 1.9 | 4.0 | 4.2 |
| 6 | Hippopotamus | 1.8 | 4.5 | 4 |
| 7 | Javan rhinoceros | 1.75 | 2.3 | 3.8 |
| 8 | Black rhinoceros | 1.1 | 2.9 | 4 |
| 9 | Giraffe | 1.0 | 2 | 5.15 |
| 10 | Gaur | 0.95 | 1.5 | 3.8 |
Tunicates (''Tunicata'')
The largest tunicates are Synoicum pulmonaria, found at depths of, and are up to 14 centimetres in diameter. It is also present in the northwestern Atlantic Ocean, around the coasts of Greenland and Newfoundland, but is less common here than in the east, and occurs only at depths between.;Entergonas
;Pleurogonas
;Aspiraculates
Thaliacea
The largest thaliacean, Pyrosoma atlanticum, is cylindrical and can grow up to 60 cm long and 4–6 cm wide. The constituent zooids form a rigid tube, which may be pale pink, yellowish, or bluish. One end of the tube is narrower and is closed, while the other is open and has a strong diaphragm. The outer surface or test is gelatinised and dimpled with backward-pointing, blunt processes. The individual zooids are up to long and have a broad, rounded branchial sac with gill slits. Along the side of the branchial sac runs the endostyle, which produces mucus filters. Water is moved through the gill slits into the centre of the cylinder by cilia pulsating rhythmically. Plankton and other food particles are caught in mucus filters in the processes as the colony is propelled through the water. P. atlanticum is bioluminescent and can generate a brilliant blue-green light when stimulated.;Doliolida
;Salps
;Larvaceans
Cephalochordates (''Leptocardii'')
The largest lancelets: European lancelet "primitive fish". It can grow up to 6 cm long.Vertebrates
Mammals (''Mammalia'')
The blue whale is the largest mammal.The largest land mammal extant today is the African bush elephant. The largest extinct land mammal known was long considered to be Paraceratherium orgosensis, a rhinoceros relative thought to have stood up to tall, measured over long and may have weighed about 17 tonnes. In 2015, a study suggested that one example of the proboscidean Palaeoloxodon namadicus may have been the largest land mammal ever, based on extensive research of fragmentary leg bone fossils from one individual, with a maximum estimated size of 22 tonnes.
Stem-mammals (''Synapsida'')
The Triassic era Lisowicia bojani, from what is now the southern Poland, probably was the largest of all non-mammalian synapsids, at and 9 tonnes. However, one study suggested a more conservative weight of 4.87 tonnes to 7.02 tonnes for the adult taxon, with an average body mass of 5.88 tonnes. The largest carnivorous synapsid was Anteosaurus from what is now South Africa during Middle Permian epoch. Anteosaurus was long, and weighed about.;Pelycosauria
;Therapsida
Reptiles (''Reptilia'')
The largest living reptile, a representative of the order Crocodilia, is the saltwater crocodile of Southern Asia and Australia, with adult males being typically long. The largest confirmed saltwater crocodile on record was long, and weighed about. Unconfirmed reports of much larger crocodiles exist, but examinations of incomplete remains have never suggested a length greater than. Also, a living specimen estimated at and has been accepted by the Guinness Book of World Records. However, due to the difficulty of trapping and measuring a very large living crocodile, the accuracy of these dimensions has yet to be verified. A specimen named Lolong caught alive in the Philippines in 2011 was found to have measured in length.The Komodo dragon, also known as the "Komodo monitor", is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang, Nusa kode and Padar. A member of the monitor lizard family, it is the largest living species of lizard, growing to a maximum length of in rare cases and weighing up to approximately.
Heaviest living reptiles
The following is a list of the heaviest living reptile species ranked by average weight, which is dominated by the crocodilians. Unlike mammals, birds, or fish, the mass of large reptiles is frequently poorly documented and many are subject to conjecture and estimation.| Rank | Animal | Average mass | Maximum mass | Average total length |
| 1 | Saltwater crocodile | 450 | 2,000 | 4.5 |
| 2 | Nile crocodile | 410 | 1,090 | 4.2 |
| 3 | Orinoco crocodile | 380 | 1,100 | 4.1 |
| 4 | Leatherback sea turtle | 364 | 932 | 2.0 |
| 5 | Black caiman | 350 | 1,100 | 3.9 |
| 6 | American crocodile | 335 | 1,000 | 4.0 |
| 7 | Gharial | 250 | 977 | 4.5 |
| 8 | American alligator | 240 | 1,000 | 3.4 |
| 9 | Mugger crocodile | 225 | 700 | 3.3 |
| 10 | Tomistoma | 210 | 500 | 4.0 |
| 11 | Aldabra giant tortoise | 205 | 360 | 1.4 |
| 12 | Loggerhead sea turtle | 200 | 545 | 0.95 |
| 13 | Green sea turtle | 190 | 395 | 1.12 |
| 14 | Slender-snouted crocodile | 180 | 325 | 3.3 |
| 15 | Galapagos tortoise | 175 | 400 | 1.5 |
Dinosaurs (''Dinosauria'')
Dinosaurs are now extinct, except for birds, which are theropods.;Sauropods
;Theropods
;Armored dinosaurs
;Ornithopods
;Ceratopsians
Birds (''Aves'')
The largest living bird, a member of the Struthioniformes, is the common ostrich, from the plains of Africa and Arabia. A large male ostrich can reach a height of and weigh over. A mass of has been cited for the common ostrich but no wild ostriches of this weight have been verified. Eggs laid by the ostrich can weigh and are the largest eggs in the world today.is the biggest of the living birds of prey
The largest bird in the fossil record may be the extinct elephant birds of Madagascar, which were related to the ostrich. They exceeded in height and. The last of the elephant birds became extinct about 300 years ago. Of almost exactly the same upper proportions as the largest elephant birds was Dromornis stirtoni of Australia, part of a 26,000-year-old group called mihirungs of the family Dromornithidae. The largest carnivorous bird was Brontornis, an extinct flightless bird from South America which reached a weight of and a height of about. The tallest carnivorous bird was Kelenken, which could reach 3 to 3.2 meters in height and 220 to 250 kilograms. The tallest bird ever was the giant moa, part of the moa family of New Zealand that went extinct around 1500 AD. This particular species of moa stood up to tall, but weighed about half as much as a large elephant bird or mihirung due to its comparatively slender frame.
The heaviest bird ever capable of flight was Argentavis magnificens, the largest member of the now extinct family Teratornithidae, found in Miocene-aged fossil beds of Argentina, with a wingspan up to, a length of up to, a height on the ground of up to and a body weight of at least. Pelagornis sandersi is thought to have had an even larger wingspan of about, but is only about, half the mass of the former.
Heaviest living bird species
The following is a list of the heaviest living bird species based on maximum reported or reliable mass, but average weight is also given for comparison. These species are almost all flightless, which allows for these particular birds to have denser bones and heavier bodies. Flightless birds comprise less than 2% of all living bird species.| Rank | Animal | Binomial Name | Average mass | Maximum mass | Average total length | Flighted |
| 1 | Ostrich | Struthio camelus | 104 | 156.8 | 210 | No |
| 2 | Somali ostrich | Struthio molybdophanes | 90 | 130 | 200 | No |
| 3 | Southern cassowary | Casuarius casuarius | 45 | 85 | 155 | No |
| 4 | Northern cassowary | Casuarius unappendiculatus | 44 | 75 | 149 | No |
| 5 | Emu | Dromaius novaehollandiae | 33 | 70 | 153 | No |
| 6 | Emperor penguin | Aptenodytes forsteri | 31.5 | 46 | 114 | No |
| 7 | Greater rhea | Rhea americana | 23 | 40 | 134 | No |
| 8 | Domestic turkey/wild turkey | Meleagris gallopavo | 13.5 | 39 | 100 - 124.9 | Yes |
| 9 | Dwarf cassowary | Casuarius bennetti | 19.7 | 34 | 105 | No |
| 10 | Lesser rhea | Rhea pennata | 19.6 | 28.6 | 96 | No |
| 11 | Mute swan | Cygnus olor | 11.87 | 23 | 100-130 | Yes |
| 12 | Great bustard | Otis tarda | 10.6 | 21 | 115 | Yes |
| 13 | King penguin | Aptenodytes patagonicus | 13.6 | 20 | 92 | No |
| 14 | Kori bustard | Ardeotis kori | 11.4 | 20 | 150 | Yes |
| 14 | Trumpeter swan | Cygnus buccinator | 11.6 | 17.2 | 138-165 | Yes |
| 15 | Wandering albatross | Diomedea exulans | 11.9 | 16.1 | 107-135 | Yes |
| 16 | Whooper swan | Cygnus cygnus | 11.4 | 15.5 | 140-165 | Yes |
| 17 | Dalmatian Pelican | Pelecanus crispus | 11.5 | 15 | 183 | Yes |
| 18 | Andean condor | Vultur gryphus | 11.3 | 14.9 | 100-130 | Yes |
Amphibians (''Amphibia'')
The largest living amphibian is the South China giant salamander. Formerly considered conspecific with the Chinese giant salamander, the maximum size of this nearly human-sized river-dweller is and almost. Before amniotes became the dominant tetrapods, several giant amphibian proto-tetrapods existed and were certainly the dominant animals in their ecosystems. The largest known was the crocodile-like Prionosuchus, which reached a length of.;Frogs
ranks as the largest toad in the world
;Caecilians
;Salamanders
Fish
Invertebrates
Sponges (''Porifera'')
The largest known species of sea sponge is the giant barrel sponge, Xestospongia muta. These massively built sponges can reach in height and can be about the same thickness at the thickest part of the "body". Some of these creatures have been estimated to be over 2,400 years of age.;Calcareous sponges
;Hexactinellid sponges
Cnidarians (''Cnidaria'')
The lion's mane jellyfish is the largest cnidarian species, of the class Scyphozoa. The largest known specimen of this giant, found washed up on the shore of Massachusetts Bay in 1870, had a bell diameter of, a weight of. The tentacles of this specimens were as long as and were projected to have a tentacular spread of about making it one of the longest extant animals.;Corals and sea anemones
;Hydrozoans
Flatworms (''Platyhelminthes'')
;Monogenean flatworms;Flukes
;Tapeworms
Roundworms (Nematoda)
The largest roundworm, Placentonema gigantissima, is a parasite found in the placentas of sperm whales which can reach up to in length.Segmented worms (Annelida)
The largest of the segmented worms is the African giant earthworm. Although it averages about in length, this huge worm can reach a length of as much as and can weigh over. Only the giant Gippsland earthworm, Megascolides australis, and a few giant polychaetes, including the notorious Eunice aphroditois, reach nearly comparable sizes, reaching, respectively.Echinoderms (Echinodermata)
The largest species of echinoderm in terms of bulk is probably the starfish species Thromidia gigas, of the class Asteroidea, which reaches a weight of over, but it might be beaten by some giant sea cucumbers such as Thelenota anax. However, at a maximum span of, Thromidia gigas is quite a bit shorter than some other echinoderms. The longest echinoderm known is the conspicuous sea cucumber Synapta maculata, with a slender body that can extend up to. In comparison, the biggest sea star is the brisingid sea star Midgardia xandaros, reaching a span of, despite being quite slender. Evasterias echinosoma is another giant echinoderm and can measure up to across and weigh.;Crinoids
;Sea urchins and allies
;Sea cucumbers
;Brittle stars
;Sea stars
Ribbon worms (Nemertea)
The largest nemertean is the bootlace worm, Lineus longissimus. A specimen found washed ashore on a beach in St. Andrews, Scotland in 1864 was recorded at a length of.Mollusks (Mollusca)
Both the largest mollusks and the largest of all invertebrates are the largest squids. The colossal squid is projected to be the largest invertebrate. Current estimates put its maximum size at long and, based on analysis of smaller specimens. In 2007, authorities in New Zealand announced the capture of the largest known colossal squid specimen. It was initially thought to be and. It was later measured at long and in weight. The mantle was long when measured.The giant squid was previously thought to be the largest squid, and while it is less massive and has a smaller mantle than the colossal squid, it may exceed the colossal squid in overall length including tentacles. One giant squid specimen that washed ashore in 1878 in Newfoundland reportedly measured in total length, head and body length, in diameter at the thickest part of mantle, and weighed about. This specimen is still often cited as the largest invertebrate that has ever been examined. However, no animals approaching this size have been scientifically documented and, according to giant squid expert Steve O'Shea, such lengths were likely achieved by greatly stretching the two tentacles like elastic bands.
;Aplacophorans
;Chitons
, the largest bivalve
;Bivalves
;Gastropods
;Cephalopods
Velvet worms (Onychophora)
Solórzano's velvet worm is the largest velvet worm known. An adult female was recorded to have a body length of 22 cm.Arthropods (Arthropoda)
The largest arthropod known to have existed is the eurypterid Jaekelopterus, reaching up to in body length, followed by the millipede relative Arthropleura at around in length. Among living arthropods, the Japanese spider crab is the largest in overall size, the record specimen, caught in 1921, had an extended arm span of and weighed about. The heaviest is the American lobster, the largest verified specimen, caught in 1977 off of Nova Scotia weighed and its body length was. The largest land arthropod and the largest land invertebrate is the coconut crab, up to long and weighing up to on average. Its legs may span.Arachnids (Arachnida)
Both spiders and scorpions include contenders for the largest arachnids.;Spiders
;Scorpions
;Pseudoscorpions
Crustaceans (Crustacea)
The largest crustaceans are crab Tasmanian giant crab and a carapace width of up to. It is the only species in the genus Pseudocarcinus. Males reach more than twice the size of females. It has a white shell with claws that are splashed in red. The females' shells change colour when they are producing eggs. At a length of up to, Lysiosquillina maculata is the largest mantis shrimp in the world. L. maculata may be distinguished from its congener L. sulcata by the greater number of teeth on the last segment of its raptorial claw, and by the colouration of the uropodal endopod, the distal half of which is dark in L. maculata but not in L. sulcata. There is a small artisanal fishery for this species. Tasmanian giant freshwater crayfish in weight and over long have been known in the past, but now, even individuals over are rare. The species is only found in Tasmanian rivers flowing north into the Bass Strait below above sea level, and is listed as an endangered species on the IUCN Red List.;Branchiopods
;Barnacles and allies
;Ostracods
;Amphipods, isopods, and allies
;Remipedes
Horseshoe crabs (Xiphosura)
The four modern horseshoe crabs are of roughly the same sizes, with females measuring up to in length and in weight.Sea spiders (Pycnogonida)
The largest of the sea spiders is the deep-sea species Colossendeis colossea, attaining a leg span of nearly.Trilobites (Trilobita)
Some of these extinct marine arthropods exceeded in length. A nearly complete specimen of Isotelus rex from Manitoba attained a length over, and an Ogyginus forteyi from Portugal was almost as long. Fragments of trilobites suggest even larger record sizes. An isolated pygidium of Hungioides bohemicus implies that the full animal was long.Myriapods (Myriapoda)
;Centipedes''
;Millipedes
;Symphylans
Insects (Insecta)
s, a class of Arthropoda, are easily the most numerous class of organisms, with over one million identified species, and probably many undescribed species. The heaviest insect is almost certainly a species of beetle, which incidentally is the most species-rich order of organisms. Although heavyweight giant wetas are known, the elephant beetles of Central and South America, and, the Titan beetle of the neotropical rainforest or the Goliath beetles, and, of Africa's rainforest are thought to reach a higher weight. The most frequently crowned are the Goliath beetles, the top known size of which is at least and. The elephant beetles and titan beetle can reach greater lengths than the Goliath, at up to, respectively, but this is in part thanks to their rather large horns. The Goliath beetle's wingspan can range up to.Some moths and butterflies have much larger areas than the heaviest beetles, but weigh a fraction as much.
The longest insects are the stick insects, see below.
Representatives of the extinct dragonfly-like order Protodonata such as the Carboniferous Meganeura monyi of what is now France and the Permian Meganeuropsis permiana of what is now North America are the largest insect species yet known to have existed. These creatures had a wingspan of some and a mass of over, making them about the size of a crow.
;Cockroaches and termites
;Beetles
;Earwigs
;True flies
, the largest fly
;Mayflies
;True bugs
walking over land
;Ants and allies
;Moths and allies.
;Mantises
;Alderflies and allies
;Net-winged insects
;Dragonflies
;Grasshoppers and allies
;Stick insects
;Lice
;Stoneflies
;Booklice
;Fleas
;Silverfishes and allies
;Thrips
;Caddisflies
Fungi
The largest living fungus may be a honey fungus of the species Armillaria ostoyae.A mushroom of this type in the Malheur National Forest in the Blue Mountains of eastern Oregon, U.S. was found to be the largest fungal colony in the world, spanning of area. This organism is estimated to be 2,400 years old. The fungus was written about in the April 2003 issue of the Canadian Journal of Forest Research. While an accurate estimate has not been made, the total weight of the colony may be as much as 605 tons. If this colony is considered a single organism, then it is the largest known organism in the world by area, and rivals the aspen grove "Pando" as the known organism with the highest living biomass. It is not known, however, whether it is a single organism with all parts of the mycelium connected.
A spatial genetic analysis estimated that a specimen of Armillaria ostoyae growing over in northern Michigan, United States weighs 440 tons. Approximations of the land area of the Oregon "humongous fungus" are has only a stipe, and a pileus up to across. There are many other fungi which produce a larger individual size mushroom. The largest known fruiting body of a fungus is a specimen of Phellinus ellipsoideus found on Hainan Island. The fruiting body masses up to.
Until P. ellipsoideus replaced it, the largest individual fruit body came from Rigidoporus ulmarius. R. ulmarius can grow up to, tall, across, and has a circumference of up to.
Protists
Amoebozoans ([Amoebozoa])
Euglenozoans ([Euglenozoa])
Rhizarians ([Rhizaria])
Alveolates ([Alveolata])
Stramenopiles ([Stramenopila])
Bacteria
The largest known species of bacterium is Thiomargarita namibiensis, which grows to in diameter, making it visible to the naked eye and a thousand times the size of more typical bacteria.- Cyanobacteria
Viruses
Both these viruses infect amoebas specifically.