n the deepest and coldest parts of the ocean, sea creatures — mainly invertebrates, or animals without backbones — can reach gargantuan proportions. Squids, sea spiders, worms and a variety of other types of animals grow to sizes that dwarf related species around the world. The phenomenon is called gigantism.
The colossal squid (Mesonychoteuthis hamiltoni) in subantarctic waters is about 14 times longer than the arrow Squid (Nototodarus sloanii) common to New Zealand, according to Te Ara the Encyclopedia of New Zealand(opens in new tab). Deep in the remote Pacific waters there’s a sea sponge the size of a minivan. But what is it about deep and frigid ocean waters that causes creatures to grow so big? It may be that survival demands it, and factors in the extremely cold waters enable it to happen.
