Page 151 - Design in Nature

Design and Creation 149

body. This eliminates the need for a giant pump to continually pump oxygen.
Its heart is shaped like a tube and beats at such a low rate that the jumps do
not affect it at all.
Scientists discovered through research that the leg muscles of fleas are not
as strong as the jumps would really require. The extraordinary performance
enjoyed by fleas is made possible by a kind of spring system that is added to
its legs, which works because of a rubberlike protein called "resilin", where the
flea stores mechanical energy. The outstanding property of this substance is its
ability to release in stretching up to 97% percent of the energy that is stored in
it. The most flexible material in the market today has a ratio of 85%. This elastic
material is located at the base of the large hind legs of the animal in tiny pads.
The flea takes a few tenths of seconds to compress this material as it folds it s
legs in preparation for a jump. A ratchetlike structure holds the leg folded until
a muscle is relaxed and the spring-like structure powers the jump through
stored energy in the resilin which translates into tremendous leaps.

Another creature as interesting as the flea, is a species of minute insect living on the flea.
These microscopic creatures reside under the armoured plates of the flea.