UGG is not a brand name, but a general name for a type of shoes. UGG boots are derived from Ugly boots (ugly shoes), commonly known as snow boots (also specifically referring to fur-integrated snow boots). They emerged in Australia during World War I. Australian pilots wrapped two pieces of sheepskin into shoes and wore them on their feet. To keep out the cold, it gradually became popular in Australia. The more popular brands now include: UGG snow boots from UGG Australia, JOMVOX, Yellow Earth, MOU, EMU and other brands.