Thursday, June 26, 2014

Did a Giant Squid Kill Shark Alpha?

What killed Shark Alpha? The in-the-box explanation is that a larger great white shark did it, but a more exotic explanation would be more interesting and may turn out to have the added benefit of being true. The three most common exotic explanations are that a megalodon did it, or a killer whale, or a giant or colossal squid.
My colleague Brent Swancer has already addressed the popular theory that a megalodon did it. I don’t think it’s plausible that a killer whale did it, since killer whales typically have an internal body temperature similar to that of humans and the culprit we’re looking for had a much lower internal body temperature of 78°F. That leaves giant and colossal squids. They’re certainly big and carnivorous enough, and—since they have only been recently discovered, after millennia of being a tall tale—they represent everything we don’t know about the ocean. The noted marine biologist, inventor, and conservationist Edith Widder helped capture the first footage of a giant squid eating dinner, and what she had to say about it has some interesting implications:
“Had this animal had its feeding tentacles intact and fully extended, it would have been as tall as a two-story house. How could something that big live in our ocean and yet remain unfilmed until now? We’ve only explored about 5 percent of our ocean; there are great discoveries yet to be made down there, fantastic creatures representing millions of years of evolution and possibly bioactive compounds that could benefit us in ways that we couldn’t yet imagine.”
But as large and as fascinating as these creatures are, there are three good reasons to believe a squid wasn’t responsible for Shark Alpha’s death.
The first is that squids are cold-blooded. There’s no reason to believe that any known species of squid would have a 78°F body temperature in 46°F water.
The second is depth. This predator hunted only a few hundred feet below the surface of the water, then dragged its prey 1,900 feet deep. Squid typically hunt much deeper; giant squid seldom surface less than 1,000 feet deep, and colossal squid are typically found a mile or more underwater.
The third is that this just isn’t how squids typically hunt. Citing squids’ slow metabolism, an international team of marine biologists explained in one 2010 article:
“We argue that the colossal squid is not a voracious predator capable of high-speed predator–prey interactions … 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.”
The prospect that a giant or colossal squid would surface to only a few hundred feet below the water, hook a nine-foot great white shark, yank it 1,900 feet deep, consume it, and then keep it in its belly at 78°F just doesn’t align with anything we know about squid behavior or physiology. If our killer is anything like a squid, it’s an undiscovered species with an unexplored evolutionary history.