By Gail Gallessich

The sharp beak of the Humboldt squid is one of the hardest and stiffest organic materials known and it is attached to flexible tissue. Engineers, biologists, and marine scientists at UC Santa Barbara have joined forces to discover how the soft-bodied squid can operate its knife-like beak without tearing itself to pieces.

Humboldt squid, or Dosidicus gigas, are about three feet wide and can injure a fish with one swift motion. The results of research on the animal were published in a recent issue of the journal Science. According to the article, “a squid beak can sever the nerve cord to paralyze prey for later leisurely dining.”

“Squids can be aggressive, whimsical, suddenly mean, and they are always hungry,” said Herb Waite, co-author and professor of molecular, cellular, and developmental biology. “You wouldn’t want to be diving next to one.” The creatures are very fast.

Waite found the puzzle of the squid beak compelling and he interested postdoctoral researcher and first author Ali Miserez in the study. Miserez is affiliated with the departments of materials; molecular, cellular, and developmental biology (MCDB); and the Marine Science Institute.

“I’d always been skeptical of whether there is any real advantage to ‘functionally graded’ materials, but the squid beak turned me into a believer,” said co-author Frank Zok, professor and associate chair of materials.

“Here you have a cutting tool that’s extremely hard and stiff at its tip and is attached to a material—the muscular buccal mass—that has the consistency of Jell-o,” said Zok.

“In the case of the squid beak,” he continued, “nature takes care of the problem by changing the beak composition progressively, rather than abruptly, so that its tip can pierce prey without harming the squid in the process. It’s a truly fascinating design!”

Zok explained that most human engineered structures are made of combinations of very different materials, such as ceramics, metals,or plastics. Joining them together requires either some sort of mechanical attachment like a rivet, a nut and bolt, or an adhesive like epoxy. But these approaches have limitations.

“If we could reproduce the property gradients that we find in squid beak, it would open new possibilities for joining materials,” explained Zok. “This could really revolutionize the way engineers think about attaching materials.”

According to Waite, the researchers were helped by the fact that squid now seem to be moving north from areas where they have been traditionally concentrated, such as deep waters off the Mexican coast. Recently, Humboldt squid have been found in large numbers in Southern California waters.

The other co-authors on the Science article are Todd Schneberk, with materials research and MCDB, and Chengjun Sun, with MCDB and the Marine Science Institute.