Ethology is the study of animal behaviour. The father of this branch of science is Konrad Lorenz. He observed animal behaviour and the process called imprinting, where an animal knew its parents by sight and by sound.
He conducted experiments to see if ducklings, when hatched, would see him first. The young hatchlings thought Lorenz was their mother, and followed him everywhere. He then did it with objects. This study is interesting because he discovered that instincts are a way of behaving from birth and there are learned behaviours that are taught.
The video below explains animal behaviour.