page_title: Cephalopod size
section_title: Scientifically validated records
hierarchical_section_title: Cephalopod size / Maximum size / Scientifically validated records
caption_attribution_description: English: Beak of the Colossal squid Mesonychoteuthis hamiltoni, Amundsen Sea, Antarctica
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.
context_section_description: Squids are the largest living cephalopods in terms of each of mantle length, total length, and mass, with the largest species by at least two of these measures being the colossal squid, Mesonychoteuthis hamiltoni. Reaching an estimated 3 m (9.8 ft) in mantle length and 10 m (33 ft) in total length, and weighing as much as 495 kg (1,091 lb), this species is also the largest of all extant invertebrates (Rosa & Seibel, 2010; McClain et al., 2015; Rosa et al., 2017). The only other squid that approaches these dimensions is the giant squid of the genus Architeuthis, with females up to 275 kg (606 lb), 2.4 m (7.9 ft) in mantle length, and possibly as much as 15 m (49 ft) in total length, making it likely the longest of all cephalopods (McClain et al., 2015). The two largest octopus species—Enteroctopus dofleini and Haliphron atlanticus—can both exceed 70 kg (150 lb), and the former has a maximum total length of more than 6 m (20 ft). Cirrate (finned) octopods can also reach a large size, with the largest captured specimen likely being a Cirrothauma magna of 1.7 m (5.6 ft) total length and 33 cm (13 in) mantle length (Collins et al., 2001; Collins & Villanueva, 2006:294), though observations from submersibles suggest that members of this group can exceed 4 m (13 ft) in total length (Voss, 1988; Vecchione et al., 2008). Members of the other cephalopod groups are substantially smaller, although the largest cuttlefish can exceed 10 kg (22 lb) in weight and 50 cm (1.6 ft) in mantle length. Cephalopods of comparable size to the largest present day squid are known from fossil remains, including enormous examples of ammonoids, belemnoids, nautiloids, orthoceratoids, teuthids, and vampyromorphids (see Teichert & Kummel, 1960; Stevens, 1988; Eyden, 2003b; Larson, 2010; Iba et al., 2015).
  What follows is an overview of the present state of scientific knowledge on the maximum size of the eight extant cephalopod species (six squids and two octopuses) that are known or estimated to reach at least 50 kg (110 lb) in mass. Extinct taxa are considered separately at the end.
caption: Beak of a colossal squid from the Amundsen Sea off Antarctica. This species has the largest beak among living cephalopods (Carnall, 2017; Hanlon & Messenger, 2018:265), with a lower rostral length around twice that of the giant squid (Young, 2003).
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