Caviar is a delicacy made from the roe of certain fish, and the sources of this delicacy are belugas, sturgeons, and roes. Belugas are a species of whale found in the Arctic and North Atlantic oceans, and their roe is considered to be one of the most expensive types of caviar. Sturgeons are a type of fish found in the Northern Hemisphere, and their roe is also highly sought after for its flavor and texture. Roes are the eggs of any fish, and they can be used to make caviar as well.