The Celts were animists: they believed that all aspects of the natural world contained spirits, divine entities with which humans could establish a rapport: animals themselves thus possessed sanctity and symbolism. They were perceived as being at the same time similar to and very different from humans. Certain creatures were observed to have particular physical or mental qualities and characteristics, and distinctive patterns of behaviour. An animal, like a stag or horse, could be admired for its beauty, speed or virility. Dogs were seen to be keen-scented, useful in hunting, guarding and in healing themselves. Snakes are destructive, fertile and have the curious habit of sloughing their skin. Birds are keen-sighted and are able to fly, leaving behind the bonds of earth. Thus, admiration and acknowledgement of a beast’s essential nature led easily to reverence of those qualities and abilities which humans either did not possess at all or possessed only partially.