The blue whale is believed to be the largest animal to have ever lived.

Īmong animals, the largest species are all marine mammals, specifically whales. At 8 kilometres (5 mi) across, and estimated at around 100,000 years old, it may be one of the largest and oldest clonal colonies on Earth. In 2006 a huge clonal colony of Posidonia oceanica was discovered south of the island of Ibiza. Even if such colonies are excluded, trees retain their dominance of this listing, with the giant sequoia being the most massive tree. Pando, a clonal colony of the quaking aspen tree, is widely considered to be the largest such organism by mass. If considered singular entities, the largest organisms are clonal colonies which can spread over large areas. The organism sizes listed are frequently considered 'outsized' and are not in the normal size range for the respective group. This article lists the largest species for various types of organisms and mostly considers extant species. The Great Barrier Reef is the world's largest structure composed of living entities, stretching 2,000 km (1,200 mi), but contains many organisms of many types of species. Some organisms group together to form a superorganism (such as ants or bees), but such are not classed as single large organisms. The largest organisms now found on Earth can be determined according to various aspects of an organism's size, such as: mass, volume, area, length, height, or even genome size. It is widely held to be the world's most massive single organism. Although it appears to be multiple trees, Pando is a clonal colony of an individual quaking aspen with an interconnected root system.

Largest whale