Humans use animals for food, sports, livestock and appreciation. Humans learn many things from animals, such as equipment and tools which humans base upon animal body parts or even architecture inspired by animal habitats. Nowadays, humans also study the molecules and genetic materials of animals. Due to the interaction between humans and animals, humans have to study animals behaviour. If humans have good understanding about animals, animal behaviour would be in control.
In the past, humans do not know how to raise animals for food. They were hunters and the behaviour of those animals that were the prey were learned. So animals taught us many styles of hunting, such as chasing animals until they were off cliffs, herding animals into traps and developing animal-killing weapons. These could not be created if we did not understand animal behaviour.
When humans started domesticating animals, they had a clear purpose of domestication. For example, chicken or cattle were domesticated for meat or other products; elephants, horses, donkeys, mules and hounds were domesticated for labour; cats, dogs and birds were domesticated to be friends. Humans study animal behaviour of livestock to increase products from animals. Some animal behaviour is selected for animal breeding to get animals with desirable behaviour.