colossal squid (mesonychoteuthis hamiltoni)
The Colossal Squid is believed to be the largest squid species. Though it is known from only a few specimens, current estimates put its maximum size at 39–46 feet long, based on analysis of smaller and immature specimens, making it the largest known invertebrate. Unlike the giant squid, whose arms and tentacles only have suckers lined with small teeth, the Colossal Squid's limbs are also equipped with sharp hooks, some swiveling, others three-pointed. Its body is wider and stouter, and therefore heavier, than that of the giant squid. Colossal Squids are believed to have a longer mantle than giant squids, although their tentacles are shorter. The beak of Mesonychoteuthis hamiltoni is the largest known of any squid, exceeding that of Architeuthis in size and in robustness. The Colossal Squid also has the largest eyes documented in the animal kingdom. While little is known about the life of this creature, it is believed to hunt prey such as chaetognatha, large fish like the Patagonian toothfish and other squid in the deep ocean using bioluminescence. Many sperm whales carry scars on their backs believed to be caused by the hooks of Colossal Squid. Colossal Squid are a major prey item for Antarctic sperm whales feeding in the Southern Ocean; 14% of the squid beaks found in the stomachs of these sperm whales are those of the Colossal Squid.
