In the Arctic and China, sheepskin boots have long been popular with people in rural occupations, such as sheep shearers, who have ready access to the raw materials. They are traditionally used for skiing. Their popularity increased as a result of World War I and World War II, where they were popular with aviators, because of their need to keep warm in non-pressurized planes at high altitudes.Fact: date=February 2008 An exhibit of a WWI aviator's outfit in the Canadian War Museum cites the term "fug" boots.Fact: date=February 2008 Ugg boots have also been popular with surfers and competitive swimmers since at least the 1960s, for keeping warm while out of the water. The terms ugg boots, ugh boots and ug boots have been used as generic terms for sheepskin boots in Australia since 1950s and 1960s, when they first appeared in advertising and other publications. The natural insulative properties of sheepskin gives thermostatic properties to the boots: the thick fleecy fibres on the inner part of the boots allow air to circulate and keep the feet at body temperature. This means that Ugg boots can be worn without socks or tights (even in relatively cold weather).

History

Since humans first cultivated sheep, many ancient cultures have made soft sheepskin boots.Fact: date=February 2008 Their popularity became obscured once leather tanning of more durable leather products like cowhide increased. Unlike cowhide, the sheepskin is soft and easily abraded, resulting in its usage historically reserved for non-taxing usage.Fact: date=February 2008 In modern history, apparently sheepskin boots gained in popularity as a result of World War I and World War II, when they were popular with aviators because of the need to maintain warmth in non-pressurized planes at high altitudes.Fact: date=February 2008 An exhibit of a WWI aviator's outfit in the Canadian War Museum cites the term "fug" boots. Fact: date=February 2008Ugg boots have also been popular with surfers and competitive swimmers since at least the 1960s, for keeping warm while out of the water.Fact: date=February 2008 Uggs became ubiquitous among Southern California surfers and Southern California downhill skiers, and from there, Uggs, which name comes from the Australian slang *UGH* for ugly and was thereafter used by everyone for the Aussie UGG boot, were popularized by Hollywood into the American mainstream and later the worldwide market. Fact: date=February 2008Since Ugg, by an American company and calling their label UGG@Australia, mass production moved to China in 2005, the Ugg has exploded onto the world market and gained in popularity. Uggs have been identified as a fashion trend for both sexes since the early 2000s. Like fashion throughout history, Ugg boots ride the vagaries of fashion trends, with a growth in popularity for men tied to increased celebrity usage (e.g., actor Leonardo DiCaprio in Uggs). Men and Women especially college age, teens, and tweens wear Uggs with jeans, dresses, shorts and long shirts or sweaters with leggings, footless tights, or knee socks and sometimes without any legwear. Or uggs are worn with jeans tucked in.