What is the largest living land animal?

The blue whale population in Antarctica was drastically reduced by commercial whaling, which started in the southern Atlantic Ocean in 1904. Despite legal protection through the International Whaling Commission in the 1960s, illegal hunting continued until 1972. From about 125,000 individuals in 1926, numbers were reduced to about 3,000 individuals in 2018, which classifies the species as “critically endangered” on the IUCN Red List.

A remarkable number of Antarctic blue whales was recently sighted

A team of scientists led by the British Antarctic Survey (BAS) was able to share some good news when returning from their recent expedition to the sub-Antarctic island of South Georgia. They counted 55 Antarctic blue whales during their 2020 expedition, which they describe as “unprecedented”. The South Georgia Waters remain an important summer feeding ground.

Dr. Jennifer Jackson, a whale ecologist at BAS, says: “After three years of surveys, we are thrilled to see so many whales visiting South Georgia to feed again. This is a place where both whaling and sealing were carried out extensively. It is clear that protection from whaling has worked, with humpback whales now seen at densities similar to those a century earlier when whaling first began at South Georgia.”

What is WWF doing?

For many years, WWF has worked with the Southern Ocean Commission (CCAMLR) to protect the most critical habitats for iconic species such as whales, penguins, seals, seabirds and their prey – tiny Antarctic krill. In the Southern Ocean, CCAMLR has made a commitment to implement a network of marine protected areas around Antarctica, to protect a range of wildlife impacted by climate change including areas where whales feed on tiny Antarctic krill. WWF works with scientists to provide important information to help governments protect these crucial foraging areas.

“Antarctic blue whales are the largest animals on Earth and a spectacular wonder to witness in the wild. They are the true Antarctic giants. However, they are critically endangered, very slowly recovering from the impacts of 20th Century whaling. Now, we are working to protect the important foraging areas for blue whales in the Southern Ocean before it’s too late. This research reaffirms there is still hope,” says Chris Johnson, Global Lead for the Protecting Whales & Dolphins Initiative.

The largest living animal in the world is the blue whale (Balaenoptera musculus), a beast measuring upwards of 100 feet (30 meters) long. But enough about the whale. What is the largest bird, butterfly or marsupial? Live Science found 15 of the largest animals of their kind. Read on to find out who they are. 

With a wingspan measuring up to 11.5 feet (3.5 meters) long, the wandering albatross (Diomedea exulans) is the largest living bird on Earth. 

The largest bird species on record (Pelagornis sandersi) is now extinct. Its wingspan measured between 20 and 24 feet (6.1 and 7.3 m), twice as long as the modern wandering albatross's wingspan, said Daniel Ksepka, a paleontologist and curator of science at the Bruce Museum in Greenwich, Connecticut. 

The heaviest living bird is the ostrich, which weighs an average of 244 lbs. (111 kilograms). The heaviest extinct bird is either the elephant bird (Aepyornis maximus) or the moa (Dinornis robustus). While the science community is split, "if you put a gun to my head, I would say Aepyornis maximus and go with 500 kg [1,100 lbs.] as the likely mass," Ksepka said. "They were, of course, flightless."

Biggest butterfly

The Queen Alexandra's birdwing (Ornithoptera alexandrae) wins first place for largest living butterfly. Its wingspan is almost 1 foot (0.3 m) across.

However, O. alexandrae is rare — it lives in the rainforests of Papua New Guinea — and the International Union for Conservation of Nature (IUCN) lists this butterfly as endangered. 

Females of the species are brown and have a wingspan of 11 to 12 inches (28 to 31 centimeters), while the yellow, green, black and blue males are slightly smaller, with wingspans of 6.7 to 7.4 inches (17 to 19 cm) long, Live Science previously reported. 

Largest rodent

The capybara (Hydrochoerus hydrochaeris) is the king of rodents. It stands about 2 feet (60 cm) tall at its shoulders, making it the largest living rodent on Earth, according to the San Diego Zoo. 

The capybara is larger than its living relatives, cavies and guinea pigs. It can be found on land or wallowing in the water, where it can swim with its slightly webbed feet. The enormous rodents are native to South America.

Largest bivalve

Reaching lengths of up to 4 feet (1.2 m) and weighing more than 500 lbs. (227 kg), the largest living bivalve mollusk is the giant clam (Tridacna gigas).

The giant shipworm (Kuphus polythalamia) is just a tad longer, though it weighs much less. This weird marine mollusk, whose shells look like an elephant tusk, measures between 3 and 5 feet (1 and 1.5 m) long. The animal inside is black and slimy, and measures about the length of a baseball bat, Live Science reported previously. 

Largest fish

The largest fish is the whale shark (Rhincodon typus), which can reach up to 40 feet (12 m) long. The colossal fish weighs about 20.6 tons (18.7 metric tons), about the weight of two school buses. 

These filter feeders live in tropical waters in the Atlantic Ocean and Indo-Pacific. However, the gentle giants are often caught by fisheries, tangled in nets as bycatch or struck by marine vessels. The IUCN lists the fish as endangered. 

Largest marsupial

The red kangaroo (Macropus rufus) is the largest living marsupial in the world. It measures up to 5.3 feet (1.6 m) from its head to rump, and its tail can be up to 3.6 feet (1.1 m) long, according to National Geographic (opens in new tab). The marsupial weighs about 200 lbs. (90 kg). 

However, M. rufus isn't the largest kangaroo on record. That honor goes to the giant short-faced kangaroo (Procoptodon goliah), which was more than twice as heavy, at 529 lbs. (240 kg), Live Science previously reported. That animal went extinct about 15,000 years ago, according to the Australian Museum. 

The largest marsupial on record is the four-legged Diprotodon optatum, which looked somewhat like a bear. It was 5.5 feet (1.7 m) tall at its shoulders and just under 13 feet (4 m) long, and it weighed up to 6,100 lbs. (2,800 kg). This animal went extinct about 25,000 years ago, according to the Australian Museum. 

Longest snake

Out of 41 species, the reticulated python is the longest python (and snake) on record. 

The longest known reticulated python measured 26.2 feet (8 m) long, longer than five grand pianos lined up. It was found at a construction site in Malaysia in April 2016, and died shortly after its capture, Live Science previously reported. 

That Malaysian snake was longer than Medusa, the longest captive snake in the world, which measured 25.1 feet (7.7 m), according to Guinness World Records. 

Largest lizard

The fierce, fork-tongued komodo dragon (Varanus komodoensis) is the largest living lizard. 

Male Komodo dragons measure up to 10 feet (3 m) long and weigh about 200 lbs. (90 kg). Females are a bit smaller, growing up to 6 feet (1.8 m) in length, Live Science previously reported.

The speedy predators have good vision and excellent senses of smell, which help them hunt large prey such as water buffalo, deer, pigs and even humans — so keep your distance!

Largest frog

The goliath frog (Conraua goliath) is an amphibian to be reckoned with. It can grow to be longer than a foot (32 cm) and can weigh more than 7 lbs. (3.3 kg), making it the largest frog on record and as large as some house cats, according to the San Diego Zoo. 

Goliath frogs are champion jumpers, able to leap almost 10 feet (3 m) forward, the zoo reported. But don't wait for them to croak about it; these giant frogs are mute. 

Largest arthropod

Arthropods (spiders, insects and other invertebrates with hard exteriors) make up the largest animal group on Earth, but only one arthropod species can claim the title of largest by size: the Japanese spider crab (Macrocheira kaempferi).

The largest Japanese spider crab on record had a leg span of 12.5 feet (3.8 m), said James Lamsdell, an assistant professor in the Department of Geology and Geography at West Virginia University. "But all the length is in the legs," Lamsdell said. "If you think that's cheating, then the largest modern arthropod is probably the American lobster. Old ones can get to be a little over a meter [3.2 feet] in body length, although [fisheries] don't generally let them get that old anymore."

The largest extinct arthropod is Jaekelopterus rhenaniae, a giant sea scorpion that grew to be up to 8.2 feet (2.5 m) long, "and the claws, when extended, could have added about a meter to the total length," Lamsdell said.

Largest dog

The largest dog on record was Zeus, a donkey-size Great Dane from Otsego, Michigan, according to Guinness World Records. 

At shoulder height, Zeus reached 3.6 feet. When he stood on his back legs, he towered at an impressive 7 feet, 4 inches (2.2 m), taller than most basketball players, Guinness World Records reported.

Sadly, the 155-lb. (70 kg) dog had a short life. He died at age 5 in 2014.

Biggest jellyfish

The lion's mane jellyfish (Cyanea capillata) can be quite small, just 0.5 inches (1.3 cm) in diameter. It can also be astoundingly large, reaching a diameter of 6.6 feet (2 m), according to National Geographic (opens in new tab). 

Its tentacles are even longer, some topping 49 feet (15 m) long, making this the largest jellyfish on the planet. 

These jellyfish can also sting people. One lion's mane jellyfish reportedly stung from 50 to 100 people swimming off the coast of New Hampshire in 2010, Live Science previously reported. 

Largest bat

The largest bat is a sight to behold. Known to some as the golden-capped fruit bat, and to others as the golden-crowned flying fox (Acerodon jubatus), it has a wingspan of up to 5.5 feet (1.7 m), according to the Encyclopedia of Life. But these giants are light, weighing just about 2.6 lbs. (1.2 kg), according to the IUCN.

The fruit bat is native to the Philippines, where it is endangered largely because of habitat loss and hunting, the IUCN reported. 

Largest cephalopod

It may come as no surprise that the giant squid (Architeuthis dux) is the largest cephalopod, a group that includes squid, octopuses, cuttlefish and nautiluses. 

Researchers determine squid length by measuring the creatures' mantle (body length). The mantle of A. dux is more than 6.6 feet (2 m) long, but the animal's tentacles make the squid a whopping 59 feet (18 m) long in total, said Michael Vecchione, a curator of cephalopods at the Smithsonian Institution National Museum of Natural History in Washington, D.C.

The largest extinct cephalopod by shell length was the Cameroceras, which was roughly 20 feet (6 m) long. However, if you're looking at largest shell by diameter, that honor goes to the extinct Parapuzosia seppenradensis, an ammonite with a coiled shell that was 8.2 feet (2.5 m) in diameter, Vecchione said. 

Largest primate

The eastern gorilla (Gorilla beringei) takes the prize as largest primate, with a height of up to 6.2 feet (1.9 m) and a weight of roughly 450 lbs. (205 kg), according to Gorillas-World. 

These gorillas live in the mountainous forests of the Democratic Republic of Congo, Rwanda and Uganda, according to the IUCN. There are fewer than 5,000 eastern gorillas left in the wild, making them critically endangered.