The Biggest Animal in the World and 7 Massive Contenders

By: Zach Taras  | 
In 2023, a blue whale skeleton hung in the main hall of the Natural History Museum of London. Sergii Figurnyi / Shutterstock

When it comes to sheer size, the animal kingdom has some truly impressive specimens. However, to declare the biggest animal in the world, we need to clarify what kind of animal is in question.

We could break it down by largest land mammal, largest living reptile, the largest bird, largest fish, largest bird ... and so we have.


Biggest Animal in the World: Blue Whale

The largest animal in the world, is the blue whale (Balaenoptera musculus). Mature blue whales can measure anywhere from 75 to 100 feet (22.8 to 30.5 meters) from head to tail, and can weigh as much as 150 tons (136 metric tonnes).

That's as long as an 8- to 10-story building and as heavy as about 112 adult male giraffes!


These days, most adult blue whales are only 75 to 80 feet (22.8 to 24.4 meters) long; whalers hunted down most of the super giants. Female blue whales generally weigh more than the males. The largest blue whale to date is a female that weighed 389,760 pounds (176,792 kg).

A blue whale's head is so wide that an entire professional football team — about 50 people — could stand on its tongue. Its heart is as big as a small car, and its arteries are wide enough that you could climb through them.

Blue Whales Start Large, Get Even Larger

Even baby blue whales dwarf most animals. At birth, a blue whale calf is about 25 ft (7.6 meters) long and weighs more than an elephant.

And they grow up fast: During the first 7 months of its life, a blue whale drinks approximately 100 gallons (379 liters) of its mother's milk per day, putting on as much as 200 lbs (91 kg) every 24 hours. As filter feeders, adult blues whale can eat more than 4 tons (3.6 metric tonnes) of krill, a tiny shrimp-like creature, every day.


Largest Land Animal: African Elephant

The largest living land animal, as well as the largest land mammal, is the African elephant (Loxodonta africana). The average shoulder height of mature African elephants is 10 to 11 feet (3 to 3.4 meters). The heaviest recorded weight for an African elephant is 11.5 tons (10.4 metric tonnes).

Largest Land Animal: Honorable Mentions

While the African elephant takes the prize for biggest land animal, there are some other categories with impressive superlatives.


  • Largest land predator: When it comes to currently living land mammals that hunt and eat other animals, polar bears win the prize for largest. Male polar bears (Ursus maritimus) have an average weight of up to 1,760 pound (800 kg).
  • Tallest land animal: This is one you might have guessed. The giraffe (Giraffa camelopardalis) is the tallest land animal, with the height of full-grown males reaching 14 to 19 feet (4.3 to 5.7 meters) tall.
  • Largest living reptile: The saltwater crocodile (Crocodylus porosus) is a massive, toothy beast, native to southeast Asia, the east coast of India, and northern Australia and Micronesia. Adult males can have a length of 20 feet (6 meters), and weigh in at 2,200 to 3,300 pounds (1,000 to 1,500 kg). It's not the largest crocodile ever, but it's the largest currently living.


Largest Living Bird: Ostrich

The world's largest animals, when it comes to the avian species, are ostriches (Struthio camelus). The largest specimens, usually adult males, can reach up to 320 pounds (145 kg) in weight, and a height of 9 ft (2.7 meters).


Largest Fish: Whale Shark

We know that there are some big aquatic mammals out there, but what about fish? In this case, the prize goes to the whale shark (which is honestly kind of fitting).

Whale sharks (Rhincodon typus) have an average length of 40 feet (12.2 meters), and the largest recorded specimen measured 61.7 feet (18.8 meters).


How Did the Dinosaurs Compare?

Most people believe that the largest animals to ever exist on Earth were the dinosaurs. However, one of the largest land dinosaurs, the sauropod Argentinosaurus, weighed only about 180,000 pounds (81,647 kg). That's little more than half the size of an adult blue whale.

It makes a lot of sense that the world's largest animal would be a sea creature. Land animals have to support their own weight, whereas sea creatures get some help from the water.


Biggest Animal FAQ

What is biggest animal in the world?
The largest known animal on Earth is the blue whale.
What is the biggest mammal on Earth?
The biggest mammal on Earth is the blue whale.
What is the biggest animal that has ever lived?
The biggest animal to ever live is the blue whale.
What is the smallest mammal on Earth today?
The smallest mammal on Earth today is the bumble-bee bat.
What was the largest land predator ever?
The short-faced bear (Arctotherium angustidens) roamed South America. Some research indicates that this bear may have been the largest terrestrial predator ever and one of the biggest animals in the world during its time.