What is the hat called that the English royal guards wear?

The tall, black fur hat worn by Grenadier Guards as British Royal Guards is called a bearskin because the entire hide of a black bear is required to make one. The five regiments of the British army that form the Queen's Guard require 50 to 100 new hats each year.

Britain adopted the bearskin in 1768 to distinguish their grenadiers on the battlefield and in military parades. British grenadiers, an elite group of soldiers known for their strength and named for throwing grenades, limited their use of the bearskin to ceremonies at home because its fur deteriorated during overseas travel. The Queen's Guard is responsible for guarding St. James' Palace as well as Buckingham Palace in London.