In
zoology,
deep-sea gigantism, also known as
abyssal gigantism, is the tendency for species of
invertebrates and other deep-sea dwelling animals to display a
larger size than their shallower-water relatives. Examples of this phenomenon include the
giant isopod, the
giant amphipod, the
Japanese spider crab, the
king of herrings (an
oarfish of up to 12 m), the
deepwater stingray, the
seven-arm octopus, and a number of squid species: the
colossal squid (up to 14 m in length), the
giant squid (up to 13 m),
Onykia robusta,
Taningia danae,
Galiteuthis phyllura,
Kondakovia longimana, and
bigfin squids. Some other very large fish found in the deep ocean, such as the
Greenland shark and the
Pacific sleeper shark, would not normally be considered examples because they sometimes visit the surface and are not larger than comparable species that spend more time in shallower water, such as the
great white shark.