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 The father fish then usually drives the mother fish away and it is he who watches over the eggs until the little fish are hatched.

For the sperm to join the egg in the water is not the safest way to start a baby growing. There must be many eggs and many sperms that do not meet, and if they do not meet almost immediately the sperms die, for the sperms cannot live in the water longer than three minutes.

The sperms of chickens and other birds are less likely to be lost than are the sperms of fish. The rooster places them inside the body of the hen where nothing can harm them and where they can easily find the eggs. If you have ever lived on a farm you may have seen the rooster doing this, but if you did not understand what was happening you may have thought that the rooster and the hen were fighting.

The rooster flies up on the back of the hen. While he is there an opening under his tail feathers touches an opening under the tail feathers of the hen. The rooster can then send the sperms into the body of the hen without the same danger of losing them that the shad