Pilot whales are large dolphins with a long body and bulbous head with prominent melon. They average 5 m (16 ft) in length but can reach lengths of 7.6 m (25 ft). Pilot whales are widely distributed throughout the ocean. Short-finned pilot whales are typically found in warmer waters while long-finned pilot whales are found in colder waters. Both species are distributed along the edge of the continental shelf where squid, their major food source, is abundant. These animals can be seen alone or in schools of hundreds of animals.Pilot whales are known by a variety of nick-names based on their appearance. Their bulbous melon has earned them the name “potheads,” while their black body color has coined the name “blackfish.” The dorsal fin of pilot whales also has a distinct shape. The fin is large and broad at the base. It then curves sharply at the back and has a rounded tip. Vocalizations emitted by pilot whales include echolocation clicks, whistles, and pulsed sounds. The calls of the long-finned pilot whale are usually more narrow and lower in frequency than short-finned pilot whale vocalizations. Whistles of the long-finned pilot whale range from 1 to 8 kHz with a mean duration of about 1 second. They are grouped into 7 different categories based on their frequency range including (1) level, (2) falling, (3) rising, (4) up-down, (5) down-up, (6) waver, and (7) multiple hump. Short-finned pilot whales have whistles that range in dominant frequency from 2 to 14 kHz. In the eastern tropical Pacific Ocean, their whistles were recorded from 3.6 to 6.1 kHz with an average duration of 0.4 seconds.