Why do rabbits have long ears?

Rabbits form a species which is prey for several
carnivores. Rabbits do not have any means to fight with their predators. Their only
means of protection from them is to detect them fast, and run away from them. The long
ears of rabbits help them catch sound waves in a very efficient manner. They are like
the ear trumpets which were used in the past to hear sounds in a better
manner.

In addition to providing an excellent means to
improve their ability to detect predators, the long ears of rabbits also help to keep
their body cool. This is important as the rapid speed with which they have to run to
escape from predators increases the body temperature very fast and a large surface is
required to eliminate the heat.