How Squishy Squid Handle Sharp Beaks
Researchers are always asking hard questions the rest of us would never have thought of, such as this one: How does a gelatinous squid manipulate its stiff, razor-sharp beak without turning itself into calamari in the process? The Humboldt squid (Dosidicus gigas) can sever the spinal nerve of a hapless fish with a single chomp of its beak—the better for grazing on later—but the tissue holding it in place has the consistency of Jell-O. One wrong move ought to rip the chitinous chomper right out. Right? According to a new study, the secret lies in gradations of stiffness. Researchers from the University of California, Santa Barbara, measured the beak's chemical composition and hardness at each point. They found that it consists of a changing mix of chitin, water and proteins. When the base is dry, it is about as stiff as the tip. But moisture softens the base up to 100-fold, the group reports in Science. Researchers say that advances in tailor-made "functionally graded" materials could allow two different materials to become bonded together by a third, smoothly varying substance, obviating the need of a rivet or an adhesive.