Ethology is the scientific and objective study of animal behaviour, usually with a focus on behaviour under natural conditions as well as viewing behavior as an evolutionarily adaptive trait. Animal Behaviour is studied to understand the wild and wonderful ways in which animals interact with each other, with other living beings, and with the environment. It explores ways in which animals relate to their physical environment and to other organisms and also includes topics such as how animals find and defend resources, avoid predators, choose mates, reproduce, and care for their young. Since the dawn of the 21st century, many aspects of animal behaviour that the scientific community long thought it understood have been re-examined, and new conclusions reached. Animal behaviour can be important in animal training as it enables the trainer to select the individuals best suited to perform the required task.