Largest and heaviest animals

The largest animal alive today is the blue whale. The biggest blue whale ever measured weighed 190 tonnes and was about 27.6 metres (91 ft) long.

The longest animal alive today is the lion's mane jellyfish. It can stretch up to 120 feet (36.6 m). On land, the largest living animal is the African bush elephant. These elephants live in many open areas of Africa. The biggest elephant ever found was seen in Angola. This elephant was very big.

Some animals that lived long ago were also extremely huge. One of these was a type of dinosaur called a sauropod. Another huge animal was an ancient whale called Perucetus. In April 2024, scientists identified a very large marine reptile named Ichthyotitan severnensis. There may be an even bigger one, called 'Aust Colossus'.

Heaviest living animals

The heaviest living animals are all whales. It is hard to know their exact weights because no scale can hold a whole large whale. People sometimes use special factories to help weigh them, but it is still tricky. Most weights are figured out by measuring parts of whales after they are cut up, which can lead to mistakes. Scientists also use math to guess the weight of whales based on how long they are, but this can also be wrong.

Heaviest terrestrial animals

The heaviest animals that live on land are all mammals. The African elephant is now known as two different types: the African bush elephant and the African forest elephant.

Vertebrates

Mammals (Mammalia)

Main article: List of largest mammals

The blue whale is the largest animal of all time. One blue whale weighed 190 tonnes and was 33.6 metres long. There were even longer blue whales, but they were not weighed.

The largest land mammal today is the African bush elephant. In the past, the largest land mammal was thought to be Paraceratherium, a rhino relative that may have stood up to 4.8 metres tall. More recent studies suggest the extinct elephant Palaeoloxodon namadicus might have been the largest. Other studies point to Dzungariotherium as a possible contender.

Stem-mammals (Synapsida)

The Late Triassic Lisowicia bojani from Poland was one of the largest non-mammalian synapsids. Another large synapsid was Anteosaurus from South Africa.

Reptiles (Reptilia)

The largest living reptile is the saltwater crocodile. Prehistoric reptiles were much larger. Giant crocodilomorphs could weigh a lot. The largest snake, Titanoboa, could grow very long. Marine reptiles like Archelon and Mosasaurus hoffmanni were also very big.

Dinosaurs (Dinosauria)

Dinosaurs were the largest animals to ever walk on land. The tallest and heaviest known dinosaur is an immature Giraffatitan from Tanzania. The longest dinosaur was a 25 metre long Diplodocus.

Other large sauropods include Patagotitan. Argentinosaurus might have weighed a lot. The largest known theropod is the common ostrich. Among extinct theropods, the most complete Tyrannosaurus rex specimen was 12.3 to 12.8 metres long.

Birds (Aves)

The largest living bird is the common ostrich from Africa. The largest bird in history may have been the extinct elephant birds of Madagascar.

Other large birds included Dromornis stirtoni from Australia and the giant moa from New Zealand.

Amphibians (Amphibia)

The largest living amphibian is the South China giant salamander. In the past, giant amphibian proto-tetrapods like Prionosuchus reached lengths of 9 metres.

Fish

The largest fish of all time was likely _Megalodon. The largest living fish is the whale shark. The largest living bony fish is the giant sunfish.

Invertebrate chordates

Tunicates (Tunicata)

Further information: Tunicata

The largest tunicate is Synoicum pulmonaria, found deep in the water. It can be up to 14 centimetres wide.

Another large type is the pleurogona, with the biggest being Pyura pachydermatina. This tunicate can grow longer than a metre.

Cephalochordates (Leptocardii)

Further information: Leptocardii

The largest lancelet is the European lancelet (Branchiostoma lanceolatum). It can grow up to 6 centimetres long.

Thaliacea

The largest thaliacean is Pyrosoma atlanticum, which can grow up to 60 centimetres long. It can glow blue-green when disturbed.

Doliolida (Doliolida)

The largest doliolida is also called Doliolida. These small animals are usually 1–2 centimetres long and can move fast in the water.

Salps (Salpida)

The largest salp is Cyclosalpa bakeri, measuring 15 centimetres long. Salps can form groups that look like a crown.

Larvaceans (Larvacea)

The largest larvacean is Appendicularia, with a body length of 1 centimetre not counting its tail.

Invertebrate non-chordates

Echinoderms (Echinodermata)

The largest species of echinoderm is the starfish Thromidia gigas, which can weigh over 6 kg (13 lb). The longest echinoderm is the sea cucumber Synapta maculata, which can extend up to 3 m (9.8 ft). The biggest sea star is the Midgardia xandaros, reaching a span of 1.4 m (4.6 ft).

Crinoids (Crinoidea)

The largest crinoid is the Heliometra glacialis, reaching a width of 78 cm (31 in). In the past, crinoids grew much larger, with stalk lengths up to 40 m (130 ft) in fossils.

Sea urchins and allies (Echinoidea)

The largest sea urchin is Sperosoma giganteum, which can reach a shell width of about 30 cm (12 in). The largest along the North America coast is the Pacific red sea urchin (Mesocentrotus franciscanus), with a shell up to 19 cm (7.5 in).

Sea cucumbers (Holothuroidea)

The bulkiest sea cucumber are Stichopus variegatus and Thelenota anax, weighing several pounds and reaching 1 m (3.3 ft) long. Synapta maculata can reach 3 m (9.8 ft) but is very thin.

Brittle stars (Ophiuroidea)

The largest brittle star is the basket star Astrotoma agassizii, with a span of 1 m (3.3 ft).

Sea stars (Asteroidea)

The heaviest sea star is Thromidia gigas, which can weigh over 6 kg (13 lb). The sea star with the largest diameter is Midgardia xandaros, at about 1.4 m (4.5 ft).

Flatworms (Platyhelminthes)

The largest known tapeworm is the whale tapeworm, Polygonoporus giganticus, which can grow over 30 m (98 ft).

Arrow Worms (Chaetognatha)

The largest arrow worm is Parasagitta setosa, growing to 14 mm (0.55 in) long.

Segmented worms (Annelida)

The largest segmented worm is the African giant earthworm (Microchaetus rappi), which can reach 6.7 m (22 ft) long and weigh over 1.5 kg (3.3 lb).

Ribbon worms (Nemertea)

The largest nemertean is the bootlace worm, Lineus longissimus. A specimen found in St. Andrews, Scotland in 1864 was 55 m (180 ft) long.

Mollusks (Mollusca)

The largest mollusks and all invertebrates are the largest squids. The colossal squid (Mesonychoteuthis hamiltoni) may be the largest, with estimates of 12 to 14 m (39 to 46 ft) long. The giant squid (Architeuthis dux) may be longer when including tentacles.

Aplacophorans (Aplacophora)

The largest mollusks of this group are in the genus Epimenia, reaching 30 cm (12 in) long.

Chitons (Polyplacophora)

The largest chitons is the gumboot chiton, Cryptochiton stelleri, reaching 33 cm (13 in) long and weighing over 2 kg (4.4 lb).

Bivalves (Bivalvia)

The largest bivalve mollusks is the giant clam, Tridacna gigas. This creature weighed 270 kg (600 lb), with a length of 1.14 m (3.7 ft) and depth of 0.75 m (2.5 ft).

Gastropods (Gastropoda)

The largest (longest) shell is from Syrinx aruanus at 0.91 m (3.0 ft). The largest shell-less gastropod is the giant black sea hare (Aplysia vaccaria) at 0.99 m (3.2 ft) long.

Cephalopods (Cephalopoda)

The largest giant octopus weighed 74 kg (163 lb), with a 7 m (23 ft) arm span.

Roundworms (Nematoda)

The largest roundworm, Placentonema gigantissima, is a parasite in the placentas of sperm whales, reaching up to 9 m (30 ft) long.

Velvet worms (Onychophora)

The largest velvet worm is Solórzano's velvet worm (Peripatus solorzanoi). An adult female was 22 cm (approximately 8.7 in) long.

Water bears (Tardigrada)

The largest tardigrade is Echiniscoides sigismundi, less than 2 mm (0.079 in) long.

Arthropods (Arthropoda)

The largest arthropod to have existed is the eurypterid (sea scorpion) Jaekelopterus, reaching up to 2.5 m (8.2 ft) long. The millipede relative Arthropleura was around 2.1 m (6.9 ft) long.

Among living arthropods, the Japanese spider crab (Macrocheira kaempferi) is the largest in size. The heaviest is the American lobster (Homarus americanus), with a specimen weighing 20 kg (44 lb).

Arachnids (Arachnida)

Spiders (Araneae)

The largest arachnid by length is the giant huntsman spider (Heteropoda maxima) from Laos.

Scorpions (Scorpiones)

The largest scorpions is Heterometrus swammerdami from the Indian subcontinent, reaching 29.2 cm (11.5 in) long.

Thecostracans (Thecostraca)

The largest known thecostracan Facetotecta y-larvae is Hansenocaris cristalabri, about 0.5 millimeters long.

Barnacles and allies (Cirripedia)

The largest barnacle is Balanus nubilus, reaching 15 cm (6 in) wide and 30 cm (12 in) tall.

Crustaceans (Crustacea)

The largest crustacean is the Tasmanian giant crab (Pseudocarcinus gigas), weighing 13 kilograms (29 lb). The largest mantis shrimp is Lysiosquillina maculata. Tasmanian giant freshwater crayfish (Astacopsis gouldi) can weigh 5 kilograms (11 lb) and be over 80 centimetres (31 in) long.

Branchiopods (Branchiopoda)

The largest crustaceans of this group is probably Branchinecta gigas, reaching 10 cm (3.9 in) long.

Barnacles and allies (Maxillopoda)

The largest species is Pennella balaenopterae, a copepod that lives on marine mammals. The largest barnacles is the giant acorn barnacle, Balanus nubilis, reaching 7 cm (2.8 in) wide and 12.7 cm (5.0 in) tall.

Ostracods (Ostracoda)

The largest crustaceans of this group is Gigantocypris australis, with females reaching 3 cm (1.2 in) long.

Amphipods, isopods, and allies (Peracarida)

The largest species is the giant isopod (Bathynomus pergiganteus), reaching 45 cm (18 inches) long and weighing 1.7 kg (3.7 lb).

Remipedes (Remipedia)

The largest crustaceans of this group is Godzillius robustus, up to 4.5 cm (1.8 in) long.

Horseshoe crabs (Xiphosura)

The four modern horseshoe crabs are about the same size, with females up to 60 cm (2.0 ft) long and 5 kg (11 lb).

Sea spiders (Pycnogonida)

The largest sea spiders is the deep-sea Colossendeis colossea, with a leg span of nearly 60 cm (2.0 ft).

Trilobites (Trilobita)

Some extinct marine arthropods were over 60 cm (24 in) long. One fossil of Hungioides bohemicus suggests the full animal was 90 cm (35 in) long.

Myriapods (Myriapoda)

Centipedes (Chilopoda)

The biggest centipedes is Scolopendra gigantea from the neotropics, reaching 33 cm (13 in) long.

Millipedes (Diplopoda)

Two large millipede species are Archispirostreptus gigas from East Africa and Scaphistostreptus seychellarum from the Seychelles islands.

Symphylans (Symphyla)

The largest known symphylan is Hanseniella magna from Tasmanian caves, reaching 25 mm to 30 mm (0.98 to 1.2 in) long.

Insects (Insecta)

The heaviest insect is a species of beetle. Goliath beetles can weigh at least 100 g (3.5 oz) and be 11.5 cm (4.5 in) long. Elephant beetles and titan beetles can be longer.

Cockroaches and termites (Blattodea)

The largest cockroach by weight is the Australian giant burrowing cockroach (Macropanesthia rhinoceros).

Beetles (Coleoptera)

Beetles are the largest order of organisms on earth. The most massive species are Goliathus, Megasoma, and Titanus beetles.

Earwigs (Dermaptera)

The largest earwigs is the Saint Helena giant earwig (Labidura herculeana).

True flies (Diptera)

The largest species is the neotropical Gauromydas heros.

Mayflies (Ephemeroptera)

The largest mayflies are from the genus Proboscidoplocia in Madagascar.

True bugs (Hemiptera)

The largest species is usually the giant water bug in the genus Lethocerus, with L. maximus from the Neotropics being the largest.

Ants and allies (Hymenoptera)

The largest ants are females of the African Dorylus helvolus, reaching 5.1 cm (2.0 in) long and 8.5 g (0.30 oz).

Moths and allies (Lepidoptera)

The Hercules moth (Coscinocera hercules), from New Guinea and northern Australia, has the largest wings of any living insect.

Cnidarians (Cnidaria)

The lion's mane jellyfish (Cyanea capillata) is the largest cnidarian. The largest known specimen had a bell 2.5 m (8.2 ft) wide and weighed 150 kg (330 lb). Its tentacles were up to 37 m (121 ft) long.

Corals and sea anemones (Anthozoa)

The largest sea-anemones are from the genus Discoma, with a mouth disc up to 60 cm (2.0 ft) wide.

Communities of coral can be very large, with a clonal colony of Pavona clavus over 32 by 34 meters — about the size of two basketball courts.

Hydrozoans (Hydrozoa)

The colonial siphonophore Praya dubia can reach 40–50 m (130–160 ft) long. The Portuguese man o' war (Physalia physalis) has tentacles up to 50 m (160 ft) long.

Box jellyfishes (Chirodropida)

The largest box jellyfish Chironex fleckeri has a bell usually about 16 cm (6.3 in) wide but can grow to 35 cm (14 in).

Sponges (Porifera)

The largest sea sponge is the giant barrel sponge, Xestospongia muta. These sponges can reach 2.4 m (8 ft) tall.