¡¡¡HThey point out that at a circus, for example, we may see elephants, monkeys, dogs and other animals doing quite skillful things. Perhaps you have seen them on television or in a film. If you watch closely, you may notice that the trainer always gives the animals a piece of candy or a piece of fruit as a reward. The scientists say that many different animals may be trained to do a number of simple jobs if they know they will get a reward for doing them.

¡¡¡¡Of course, ³as we know, dogs can be used to guard a house, and soldiers in both old and modern times have used geese to ⁴give warning by making a lot of noise when a stranger or an enemy comes near. But ⁵it may be possible to train animals to work in factories. In Russia, for example, pigeons, which are birds with good ⁶eyesight, are being used to ⁷watch out for faults in small steel ball that are being made in one factory. When the pigeon sees a ball which looks different from others, it touches a steel plate with its beak. This turns on a light to warn people in the factory. At the same time a few seeds are given as a reward. ⁸It takes three to five weeks to train a pigeon to do this and one pigeon can inspect 3,000 to 4,000 balls an hour.

¡¡¡¡Apes have been used in America in helping to make cars, and scientists believe that these large monkeys may one day gather crops and even drive trains.