A dog is useful in catching thieves and criminals. The thief may hide anywhere. Yet the dog will use his keen sense of smell to find out where the thief is hiding.Police dogs are used to catch murderers and criminals. The dog by his sense of smell will lead the police to the hiding place of a murderer.A dog is loyal and faithful to his master. Nothing will induce him to leave his master. His master might be a poor man or even a beggar but, still his dog will not leave him to go with anyone else. A dog worships his master as if he were a God.A dog has a sharp sense of hearing and smell. He can hear footsteps from a great distance. At night he will be up and about at the least sound. He can smell his master from far off. He will rush out of the house to jump on his master and welcome him home.A friend is one who is ready to help a man in his moment of need. So a dog is really man’s best friend. He is prepared to die rather than allow any harm to come to his master.Dogs have been known to die to save their masters. A dog might even die of grief after his master is dead. He is certainly a true and faithful friend. It is right to call him man’s best friend.