Colossal squid, giant squid, and octopus

What’s the difference between a squid and an octopus?

Both squid and octopus are cephalopods, a class of molluscs.
A typical squid has:

  • a streamlined body
  • a clear internal shell known as a gladius or pen
  • a head
  • a mantle (which fits like a hat over the main part of the body)
  • eight arms
  • two tentacles with hooks, or sucker rings, or both
  • two fins 

A typical octopus has:

  • a round, bulbous body
  • no internal shell 
  • a head
  • a mantle
  • eight arms with suckers (never hooks)
  • no tentacles and no fins
What’s the difference between a colossal squid and a giant squid?

Colossal squid (Mesonychoteuthis hamiltoni) are slightly shorter than giant squid (Architeuthis dux), but have a larger, heavier body. Te Papa’s colossal squid tips the scales at a massive 490 kg. In contrast, giant squid weigh up to about 275 kg.

All squid have sharp horny beaks made of material similar to human fingernails. The colossal squid has the largest beak of any squid, including the giant squid. The tips of the colossal squid’s tentacles (the clubs) are armed with two unusual rows of sharp, swivelling hooks, and two rows of tiny suckers. Other squid species also have tentacle hooks. The beak and the hooks are lethal weapons for catching and holding large fish like the toothfish. 

Image 01
Common New Zealand octopus (Pinnoctopus cordiformis). Courtesy of
Image 02
Common squid (Nototodarus sloanii). Courtesy of
Image 03
A mass of squid beaks from inside a sperm whale's stomach.

Courtesy of Dr Steve O'Shea
Image 04
Adult female giant squid (top left), subadult female colossal squid (bottom left, 2003 specimen), and adult male teuthologist Steve O'Shea (top right). Reproduced courtesy of Kathrin Bolstad.


For more Colossal Squid resources check out the resources section of our website.