I'm not an expert on the subject, but I think hussar headdress is also bear fur. Guards bearskins are made from the hide of the Canadian black bear, but I think most hussar regiments wear brown busbies.
Fusilier regiments in the British Army wear fur headdress which is similar in shape to a Guards bearskin, but lower and with a badge on the front, but they are made of sealskin and look quite different.
Incidentally, as Colonel in Chief of the Royal Scots Greys Nicholas II also wore a bearskin - the Grey, and their successors the Royal Scots Dragoon Guards, are the only cavalry to wear bearskins.
Ann