page_title: Largest organisms
section_title: Viruses
hierarchical_section_title: Largest organisms / Viruses
caption_attribution_description: Čeština: Náčrt viru Pithovirus sibericum. English: Sketch of Pithovirus sibericum virus.
context_page_description: 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. Some organisms group together to form a superorganism, but such are not classed as single large organisms. The Great Barrier Reef is the world's largest structure composed of living entities, stretching 2,000 km, but contains many organisms of many types of species.
  The organism sizes listed are frequently considered "outsized" and are not in the normal size range for the respective group.
  If considered singular entities, the largest organisms are clonal colonies which can spread over large areas. Pando, a clonal colony of the quaking aspen tree, is widely considered to be the largest such organism by mass. Even if such colonies are excluded, trees retain their dominance of this listing, with the giant sequoia being the most massive tree. In 2006 a huge clonal colony of Posidonia oceanica was discovered south of the island of Ibiza. At 8 kilometres across, and estimated at around 100,000 years old, it may be one of the largest and oldest clonal colonies on Earth.
context_section_description: The largest virus on record so far is the Pithovirus sibericum with the length of 1.5 micrometres, comparable to the typical size of a bacterium and large enough to be seen in light microscopes. It was discovered in March 2014 in a soil sample collected from a riverbank in Siberia. Prior to this discovery, the largest virus was the peculiar virus genus Pandoravirus, which have a size of approximately 1 micrometer and whose genome contains 1,900,000 to 2,500,000 base pairs of DNA.
  Both these viruses infect amoebas specifically.
caption: Pithovirus sibericum – the largest virus
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