The killer whale is the most cosmopolitan of all cetaceans and may be the second-most widely-ranging mammal species on the planet, after humans (Rice 1998). Killer whales can be seen in virtually any marine region, from the equator to polar waters. Although they are generally more common in nearshore areas and in higher-productivity areas and/or higher latitudes, there appear to be no hard and fast restrictions of water temperature or depth on their range. The distribution extends to many enclosed or partially-enclosed seas, such as the Mediterranean Sea, Sea of Okhotsk, Gulf of California, Gulf of Mexico, Red Sea, and Persian Gulf. However, there are only extralimital records from the Baltic Sea and no records from the Black Sea.