All living thingthings are designed to survive in their environment. Scientists hopeshope to use these designs to develop ideas for humans. This technique is called biomimetics . A toucan's bill is an example of a desinedesign that interests scientists. The brightly colored bill is about one third of the birdsbird’s size. Scientists are not completely sure about why the beak is so large and brite bright, but there are many theorys theories. someSome scientists speculate that the colorful bill is used to attract the opposite sex, open fruit, or fight off enemies. The bird's bill, or beak, areis both hard and lightweight. The outer surface of the bill is made of keratin, a substance that is found in human hair and nails. The bill is not solid, but is difficult, as it is made of an intricate structure of holes held together with bones. Cars or planes that mimik mimic, or copy, this light yet strong design could be safer for passengers.