Toucan Beaks

["Richard W. Travsky" <rtravsky@uwyo.edu>]

I thought this was way cool and of course the first thing that came to 
mind was beaks of pterosaurs and the like...

http://www.jacobsschool.ucsd.edu/news_events/releases/release.sfe?id=417

November 30, 2005 -- As a boy growing up in Brazil 40 years ago, Marc A. 
Meyers marveled at the lightweight toughness of toucan beaks that he 
occasionally found on the forest floor. Now a materials scientist and 
professor of mechanical and aerospace engineering at UCSD's Jacobs School 
of Engineering, Meyers said makers of airplanes and automobiles may 
benefit from the first ever detailed engineering analysis of toucan beaks 
conducted in his lab.
...
In a paper to be published Dec. 1 in Acta Materialia, Meyers and graduate 
students Yasuaki Seki and Matthew S. Schneider reported that the secret to 
the toucan beak's lightweight strength is an unusual bio-composite. The 
interior of the beak is rigid "foam" made of bony fibers and drum-like 
membranes sandwiched between outer layers of keratin, the protein that 
makes up fingernails, hair, and horn.
...
"The big surprise was our finding that the beak's sandwich structure also 
behaves as a high energy impact-absorption system," said Meyers.
...
The beaks interior is a highly organized matrix of stiff cancellous bone 
fibers that looks as if it was dipped into a soapy solution and dried, 
generating drum-like membranes that interconnect the fibers. The result is 
a solid foam of air-tight cells that gives the beak additional rigidity.

"The beak is mostly air," said Meyers. "While the inner part of human bone 
also contains cancellous bone, we don't have the foam interconnections, 
which produce a much stronger structure with very little additional 
weight."

Like a house covered by a shingled roof, the foam is covered with 
overlapping keratin tiles, each about 50 micrometers in diameter and 1 
micrometer thick, which are glued together to produce sheets.
...