Squids

Squid diverged from other cephalopods during the Jurassic and radiated at the beginning of the Late Cretaceous, and occupy a similar role to teleost fish as open-water predators of similar size and behaviour. They play an important role in the open-water food web. The two long tentacles are used to grab prey and the eight arms to hold and control it. The beak then cuts the food into suitable size chunks for swallowing. Many squids are rapid swimmers, moving by jet propulsion, and largely locate their prey by sight. Some species are less active, especially those inhabiting the deep sea; the colossal squid belongs to one such group, the glass squids. They are among the most intelligent of invertebrates, with groups of Humboldt squid having been observed hunting cooperatively. They are preyed on by sharks, other fish, sea birds, seals and cetaceans, particularly the specialized sperm whales.