human and animal reproductions

when god created man and woman he had a purpose- to populate planet earth. god could have created 10 billions human beings, but he created only 2 and gave them the command to be fruitful, to multiply and fill the earth. the astonishing truth is that the animals prove to be smarter than humans when it come to be fruitful and multiply. In the animal kingdoms, 2 males fight for hierarchy, but you never see them as mates. the understand the will of god.