Zap!

The following article was originally published by the University of North Carolina at Chapel Hill in the Spring 1998 issue Endeavors magazine.
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65487For generations, the monstrous-looking squid has inspired legends, tabloid headlines, and science fiction. But when you get right down to the meat of the matter, this lightning-fast creature is even more amazing than it looks.

By most accounts, squid shouldn't be able to move. But try telling that to the shrimp who just got snatched.

"The squid's prey strike is amazingly fast," says Bill Kier, associate professor of biology. "It literally happens in the blink of an eye."

The odd thing is, squid lack bones, which ordinarily are a necessity for movement.

The other necessity is muscles, but they can't do the job alone because they have one fatal flaw. Under their own power, they can only contract.
Photo by Colin Dunlop

Of course, for some movements, contraction is enough. You can bend your arm by contracting your bicep muscle. But to straighten your arm, you need the tricep muscle and the upper-arm bone.

Like kids on a seesaw, the bicep and tricep work together to move your forearm up and down. The pivot point in this case is at your elbow, where the upper-arm bone meets the forearm. To raise your forearm, the bicep contracts. To lower your forearm, the tricep -- which is on the opposite side of the upper-arm bone -- contracts, letting the bicep relax. Without the upper-arm bone, there would be no pivot and no way to lower the forearm.

So muscles, because they only know one trick, need bones to be their levers and pivots. Those parts are so critical that creatures without bones have some kind of...
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tonmo
Tony converted TONMO.com into an octopus and cephalopod interest site in May 2000. (Find out more about how TONMO started by reading this blog entry.) He began his career in the online services industry in 1992, working for companies such as Prodigy, iVillage.com, Reuters and Comcast. Tony and his wife Tania are the owners of Deep Intuition, LLC, which is an entity they created to support their entrepreneurial hobbies and pursuits. He graduated from St. Bonaventure University with a B.A. in Mass Communication and lives in Pennsylvania.

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