page_title: Cephalopod size
section_title: Extinct taxa
hierarchical_section_title: Cephalopod size / Maximum size / Largest species by measure / Extinct taxa
caption_attribution_description: 日本語: アンモナイト類のパキデスモセラス・パキディスコイデ（Pachydesmoceras pachydiscoide）の化石。北海道三笠市産出。白亜紀後期。国立科学博物館の展示。 English: Fossil of Pachydesmoceras pachydiscoide from Mikasa, Hokkaido, Japan. Late Cretaceous. Exhibit in the National Museum of Nature and Science, Tokyo, Japan.
context_page_description: Cephalopods vary enormously in size. The smallest are only about 1 centimetre long and weigh less than 1 gram at maturity, while the largest—the giant and colossal squids—can exceed 10 metres in length and weigh close to half a tonne, making them the largest living invertebrates. Living species range in mass more than three-billion-fold, or across nine orders of magnitude, from the lightest hatchlings to the heaviest adults. Certain cephalopod species are also noted for having individual body parts of exceptional size. The giant and colossal squids, for example, have the largest known eyes among living animals.
  Cephalopods were at one time the largest of all organisms on Earth, and numerous species of comparable size to the largest present day squids are known from the fossil record, including enormous examples of ammonoids, belemnoids, nautiloids, orthoceratoids, teuthids, and vampyromorphids. In terms of mass, the largest of all known cephalopods were likely the giant shelled ammonoids and endocerid nautiloids, though perhaps still second to the largest living cephalopods when considering tissue mass alone.
  Giant cephalopods have fascinated humankind since time immemorial.
caption: Giant fossil of Pachydesmoceras pachydiscoide from Mikasa, Hokkaido, Japan, exhibited at the National Museum of Nature and Science in Tokyo
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