The Shetland Sheepdog, often known as the Sheltie, is a breed of herding dog that originated in the Shetland Islands of Scotland. The topcoat consists of long, straight, water-repellent hair, which provides protection from cold and the elements. The undercoat is short, furry and very dense and helps to keep the dog warm. Mats can be commonly found behind the ears, under the elbow on each front leg, and in the fluffy fur on the hind legs (the 'skirts'), as well as around the collar (if worn). The coat is usually shed twice a year, often in spring and autumn.