In the popular imagination, the colossal squid is fast and terrifying, able to dispatch whales and submarines with ease.
But the image of the squid as a nasty predator of the deep is probably more mythology than biology argue Rui Rosa of the Laboratorio Maritimo da Guia in Lisbon and Brad Seibel of the University of Rhode Island in a new paper.
These huge squid, which can weigh more than 1,100 pounds (500kg), may have a supremely slow metabolism, allowing it to live on a measly 4.5kg of fish flesh per day.
"We argue that the colossal squid is not a voracious predator capable of high-speed predator–prey interactions,” they wrote in an April article in the Journal of the Marine Biological Association of the United Kingdom. “It is, rather, an ambush or sit-and-float predator that uses the hooks on its arms and tentacles to ensnare prey that unwittingly approach.”
Tiny squids can be quick, but their metabolisms and movements slow as they get bigger or live deeper in the ocean. By the time you get 2,000 metres down like the colossal squid, the animals exist at a slow pace. And, unlike warm-blooded leviathans like whales, they can.
Regulating temperature has a very high energy cost, so whales have to eat a lot. The cold-blooded squid, by contrast, can simply hang out and wait for some fish to come by every once in a while.