A small black bird on the back of a capybara.

Biggest animals in the world

Written by:
September 25, 2019

Biggest animals in the world

Humans may be the ones who cracked the code on cell phones, written language, and sliced bread, but the animal kingdom brings a lot to the table in terms of sheer size and strength. Yes, it was a human being who wrote "Romeo and Juliet," as was the inventor of the vacuum cleaner, but these accomplishments don't mean much to a 12-foot-wide crab or a 300-pound bird. As humans, we can only bow our heads in respect to these massive kings and queens of the animal world.

The animals included on this list all share one trait: They are larger than any other animal of their kind, which may have a little something to do with an evolutionary trend. In recent years, new research has emerged in support of Cope's rule, which posits that over generations, animals will evolve to become larger. This Stanford study found that while it's not necessarily the case that all animals have become bigger over time, those that were already on the larger side did evolve and branch off to become more diverse—which can ultimately prove beneficial in terms of survival.

That being said, there are certainly some ancient creatures whose unfathomable size would have made them an unwelcome guest in the modern world. Take the extinct Titanoboa, for instance: a 3,000-pound, 48-foot-long snake whose remains were discovered in Colombia. 

Stacker has done extensive research to create this unique list, which features the largest animals of their kind for certain categories of the animal kingdom. These categories, including mammal, bird, fish, and beyond, offer an overall look at the living beings that tower over others of their kind.

Read on to learn more about the biggest animals in the world.

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Mammal: Blue whale

The blue whale is the largest animal on Earth, and perhaps the largest ever to have existed, usually ranging between 70 and 90 feet in length (though there are records of some that have exceeded the 100-foot mark). These whales have been found in every ocean across the globe, often traveling in pairs; areas off the California coast hold the densest population. Unsurprisingly, being that big requires many calories: Blue whales can eat between 2 and 4 tons of krill (a shrimp-like crustacean) a day.

Land mammal: African bush elephant

The African bush elephant, which can weigh up to 11 tons and reach 13 feet in height, is characterized by its pronounced tusks, and large head and ears. The elephant is also notable for its dextrous and sensitive trunk, which is made up of over 40,000 muscles and tendons and thereby allows the elephant to handle objects of all sizes with ease. African bush elephants can be found in most African countries, though their survival is at stake due to both poaching concerns and habitat destruction.

Reptile: Saltwater crocodile

Despite earning the cute-sounding nickname of "saltie," the saltwater crocodile is often regarded as a fearsome creature—due to its 1,000-pound weight, massive jaws, and willingness to eat nearly any animal that wanders into its sights. These crocodiles hunt by waiting just below the surface of a body of water, then bursting out using their tails in order to catch and drown their prey. Saltwater crocodiles can be found in a variety of regions, ranging from Australia to Southeast Asia.

Lizard: Komodo dragon

The Komodo dragon's name alone is an indicator of this lizard's power and physical characteristics: It's dark and scaly, extremely strong, and uses a long, thin forked tongue to test the air for signs of nearby prey. At maturity, a Komodo dragon weighs 154 pounds on average, though the largest confirmed specimen was more than twice that size. Found in Indonesian Islands, the Komodo dragon can both eat 80% of its own body weight in one meal, and empty its stomach at will in order to reduce its weight and escape danger more quickly.

Snake: Giant anaconda

Referenced in pop culture from hip-hop songs to action movies, this jungle-dwelling snake can weigh in at around 550 pounds. Found in swampy regions of South America, and commonly known as the green anaconda, this creature not only possesses the ability to swim, but is in fact more agile in the water than on land. The mega-snake kills its prey with asphyxiation, and is known to maintain its size by dining on large animals such as pigs and deer.

Bird: Ostrich

The ostrich may not actually be able to fly, but this African bird can run at speeds of 45 miles per hour when threatened. An adult male ostrich may weigh close to 300 pounds, and can reach a height of 9 feet (about half of which comes from its neck). This last surviving member of the genus Struthio dines on things like berries and grass, and has a progressive approach to the division of household labor: Both females and males take turns guarding and tending to their eggs after a female has laid them.

Amphibian: Chinese giant salamander

Chinese giant salamanders are certainly not new on the block—they belong to the family Cryptobranchidae, ancestors of which split off from all other types of amphibians during the Jurassic period. This amphibian, whose wide mouth sometimes resembles a smile, can grow to be nearly 6 feet long, with its tail making up more than half of this overall length. The species has long been revered in China, but is currently under threat of extinction due primarily to over-harvesting and lack of habitat protection.

Invertebrates: Colossal squid

Colossal squids aren't just massive, measuring up to 45 feet or so in length in adulthood—they are also incredibly mysterious, living at extreme water depths that make gathering scientific data on them quite difficult. There have only been a few human sightings of this cephalopod in all of history: It was first identified in 1925 due to remains discovered inside a whale's stomach; since then, it has only been spotted in its entirety a handful of times. One notable feature of this elusive invertebrate is its extremely large eyes—which can be the size of basketballs.

Insect: Giant weta

This fist-sized bug has a long history: It was able to survive due to the fact that when New Zealand separated from other landmasses millions of years ago, it was left without predatory mammals. Today, the giant weta (of which there are 11 species) is the heaviest insect in existence, and mostly lives in trees. The word "weta" is derived from a phrase meaning "god of ugly things" in indigenous New Zealand language Maori, which is not inaccurate when talking about this long-horned, spiny-legged creature.

Beetle: Rhinoceros beetle

The Rhinoceros beetle has rightfully earned its common nickname "Hercules beetle," considering that some adults of the species can lift objects up to 850 times their own weight. These black, gray, or green beetles are found on every continent except Antarctica and can reach a length of about 6 inches. When threatened, it can produce a sharp hissing sound that comes from the beetle rubbing its abdomen against its wings.

Spider: Goliath bird-eating tarantula

The Goliath bird-eating tarantula's eight eyes might give the impression that it has excellent sight, but most of this spider's ability to "see" comes from using the hair on its body to sense nearby vibrations. As the biggest tarantula in the world, it boasts a body span of nearly 5 inches and a leg span of 11 inches. They are almost always solitary, pairing up only when necessary to mate.

Marine arthropod: Japanese spider crab

It only takes one look at the Japanese spider crab to understand where its name comes from: This marine arthropod bears long, spindly legs that can reach an overall span of 12 or 13 feet. Sporting an orange body and white-spotted legs, it lives in the Pacific Ocean near Japan, primarily in waters between 500 and 1,000 feet in depth. It is thought to have a life expectancy of nearly 100 years.

Rodent: Capybara

Rodent haters, look away: The capybara is the largest rodent in the world, standing about 2 feet tall at maturity. Sometimes referred to as "capys," they are native to South America; they tend to live on riverbanks so that they can feast on water plants and combat their naturally dry skin with daily swims. These hefty rodents bear shaggy brown hair and webbed feet, and are notoriously content to serve as another animal's chaise lounge.

Bony fish: Sunfish

The sunfish (also known as the mola, Latin for "millstone") can grow to weigh a whopping 2.5 tons and span 10 feet horizontally. Their large dorsal fin might scare swimmers at first, as it looks quite similar to that of a shark, but in fact the sunfish is harmless to (and unafraid of) humans. Silvery and rough skinned, these aquatic creatures can be found in tropical oceans across the globe—often soaking up sunlight near the water's surface.

Fish: Whale shark

The whale shark may be the largest shark in the world (it can reach the size of a school bus), but it easily falls into the category of "gentle giant." Whale sharks are filter feeders: Rather than seeking out and attacking other ocean creatures for sustenance, they simply swim along with their large mouths hanging open, sucking up all the plankton they pass. They can be found in many tropical oceans and are distinguishable from other kinds of sharks due to their uniquely white-spotted bodies.

Butterfly: Queen Alexandra's birdwing

With a wingspan of about 10 inches, Queen Alexandra's birdwing—which is found only in New Guinea—is the largest butterfly in existence. That's not the only place where this butterfly beats out others of its kind: It takes four months for it to become a full adult, and then it lives for three months beyond that (many other butterflies only live for about one month at most). While the females are mostly brown, the males of this species typically display neon green and aquamarine wings.

Marsupial: Red kangaroo

The small groups into which red kangaroos often congregate are referred to as "mobs," although they haven't been known thus far to participate in organized crime. They can weigh about 200 pounds and have a lifespan of up to 23 years; their powerful legs give them the ability to move at a speed of 35 miles per hour and jump 6 feet high. In spite of its large adult size, the red kangaroo is smaller than a cherry at birth and spends an additional two months inside its mother's pouch before branching out into Australia's deserts and grasslands.

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