Human curiosity often leads to questions about the largest animals on Earth. However, defining “biggest” is not always straightforward, as it can refer to different measurements such as overall mass, length, or height.
The Largest Animal on Earth
The blue whale, a marine mammal, holds the record as the largest animal known to have ever lived on Earth, surpassing even the largest dinosaurs. An average adult blue whale can reach lengths of up to 30.5 meters (100 feet), with some individuals recorded at 33 meters (110 feet). These enormous creatures can weigh an average of 181,437 kilograms (200 tons), with some reaching up to 150 metric tons (330,000 pounds).
Blue whales inhabit all the world’s oceans and undertake extensive migrations, moving to colder waters for abundant food sources and warmer regions for breeding. Despite their massive size, their diet consists almost exclusively of tiny, shrimp-like crustaceans called krill, consuming up to 3,600 kilograms (7,900 pounds) of krill daily. Their unique baleen plates, which filter krill from vast quantities of water, enable them to sustain their enormous bodies.
Giants Across Different Realms
Beyond the blue whale, other animals dominate in specific categories, showcasing remarkable size in their respective habitats.
The African bush elephant is the largest living land animal. Males typically stand between 3.04 and 3.36 meters (10 to 11 feet) tall at the shoulder and weigh between 5.2 and 6.9 metric tons (5.7 to 7.6 short tons). The largest recorded specimen reached a shoulder height of 3.96 meters (13 feet) and an estimated mass of 10.4 metric tons (11.5 short tons).
Among land carnivores, the polar bear and Kodiak bear are contenders for the largest. While the polar bear is generally considered the largest bear species, male polar bears average between 350 and 600 kilograms (770 and 1,300 pounds), with the largest recorded at 1,000 kilograms (2,210 pounds). Kodiak bears, a subspecies of brown bear, can be comparable in size, with males averaging 475 to 533 kilograms (1,050 to 1,175 pounds), and the largest wild specimen weighing 750 kilograms (1,656 pounds). Polar bears tend to be taller and longer, whereas Kodiak bears are often bulkier.
The common ostrich holds the title of the tallest and heaviest living bird. Male ostriches typically stand 2.1 to 2.75 meters (6 feet 11 inches to 9 feet) tall and weigh between 100 and 130 kilograms (220 to 290 pounds). Some exceptional individuals can weigh up to 156.8 kilograms (346 pounds).
The saltwater crocodile is recognized as the largest living reptile. Adult males can reach lengths of 6 to 6.3 meters (20 to 21 feet), though some have been recorded at up to 7 meters (23 feet). These powerful predators can weigh between 1,000 and 1,500 kilograms (2,200 and 3,300 pounds).
In the aquatic realm, the whale shark is the largest living fish. These filter feeders can reach an approximate maximum length of 18 meters (59 feet), with an average length around 12 meters (39 feet). They typically weigh about 14 metric tons (15 tons), though some larger individuals have been recorded at 21.5 tonnes (47,000 pounds).
For invertebrates, the colossal squid is the largest by mass, reaching up to 495 kilograms (1,091 pounds). Its total length can range from 9 to 15 meters (30 to 49 feet). In terms of linear dimension, the lion’s mane jellyfish is considered the longest animal, with tentacles that can extend over 36.5 meters (120 feet) in length. Its bell, or body, can measure up to 2.5 meters (7 feet) in diameter.
Defining Immense Size
Measuring the “biggest” animal involves considering various physical attributes, as a single metric rarely captures the full scope of an animal’s size. Weight, or mass, is a common measure for overall size, reflecting the total biological material of an organism. Length is particularly relevant for elongated creatures, such as marine invertebrates, while height is used for tall terrestrial animals. For flying animals, wingspan indicates their aerial reach.