Deep-sea gigantism

In zoology, deep-sea gigantism, also known as abyssal gigantism, is the tendency for species of crustaceans and other invertebrates to display a larger size than their shallow-water counterparts. One of the most extreme examples of this phenomenon is the giant squid, which can grow up to 20 metres in length.

It is not known whether this effect comes about as a result of adaptation for scarcer food resources (therefore delaying sexual maturity and resulting in an increased size) or adaptation for greater pressure. This has often been described as an apparent paradox, especially considering fish do not show the same effects.