In Native American lore, a Kolus is the younger sister of Thunderbird. The Kolus has a coat of white down so thick it makes her hot and prone to sweating. Like the Thunderbird, the Kolus has the ability to transform into a human. When overheated, the Kolus removes her down to become temporarily human. A highly respected symbol, Kolus is known as a protector spirit. In many origin stories, a Kolus flew down from heaven and shed her coat, transforming into a human and becoming the founding ancestor of the tribe or clan.