Page 85 - Design in Nature

Communication and Target Location Systems 83

after its birth, when they change and become like the normal signals of an
adult. This plays a great role in regulating the complex relationships of
motherhood and fatherhood. A father can recognise his infant, and bring it
home to safety.

Living Activities Communicated Through Signals
Fish can also communicate information other than gender and age. In all
the species of electrical fish, frequency hikes transmit alerting messages. For

instance, an elephant fish (Mormyridae) normally transmits electrical signals
with a frequency of 10 Hz. i.e.10 vibrations per second, which it can easily
increase up to 100-120 Hz. A motionless elephant fish warns opponents of an
attack. This behaviour resembles the tightening of fists before a fight. Most of
the time, this warning is powerful enough to discourage the opponent. After
a fight, the wounded party, in an electrical silence, stops sending signals for

about 30 minutes. The fish that calms down or leaves the fight usually
remains motionless. The purpose behind this is to make it harder for the
others to find them. Another purpose is to avoid hitting surrounding objects
since they become electrically blind due
to lack of signals.

Special System for Non-Confusion
of Signals
So then, what happens when an
electric fish comes near another
producing the same signals? Does this not

interfere with both their radars?
Interference would be a normal
consequence here. However, they have
been created with a natural defence An electric fish locates another one
by means of signals.
mechanism that prevents this confusion.