A、Because their owners are impatient. B、Because they hate cats very much. C、Because they have a higher prey drive. D、Because the

Most dogs can be taught to tolerate cats if their owners are willing to be patient and consistent. Some dogs take longer to train than others and the difference is usually due to the dog’s level of "prey drive".
    Nature designed the predators to chase and catch smaller animals for food. Although dogs have been domesticated for thousands of years, they still act upon the instincts nature gave them. Through generations of selective breeding, people have modified these instincts. By decreasing the effects of some and enhancing the effects of others, we’ve been able to develop a wide variety of different breeds of dogs, each meant to serve a different purpose or perform a certain function.
    A dog’s instinct to chase and catch something is called his prey drive. Throw a stuffed toy to a puppy and watch his prey drive in action as he chases it, catches it, and then shakes it to pieces. Breeds and individual dogs vary in the intensity of their prey drives. Some breeds are created specifically for killing other animals. Most terriers, for example, are intended to kill rats and they have very high prey drives.
    In other breeds, the prey drive can be altered to suit an entirely different purpose. Therefore, there must be effective ways to train a dog with a high prey drive to live peacefully with cats and other small pets. For example, by giving the dog extra attention and even special treats when the cat is in the room, the dog soon learns that having the cat around means very good things are going to happen to him! He will be happy to get along with the cat harmoniously and his prey drive will be lowered.