This article is from the Dolphin
FAQ, by Jaap van der Toorn
The deepest dive ever recorded for a bottlenose dolphin was a 300 meters (990 feet). This was accomplished by Tuffy, a dolphin trained by the US Navy. Most likely dolphins do not dive very deep, though. Many bottlenose dolphins live in fairly shallow water. In the Sarasota Bay area, the dolphins spend a considarable time in waters that are less than 2 meters (7 feet) deep. Other whale and dolphin species are able to dive to much greater depths even. The pilot whale (Globicephala melaena) can dive to at least 600 meters (2000 feet) and a sperm whale (Physeter macrocephalus) has been found entangled in a cable at more that 900 meters (500 fathoms) depth. Recent studies on the behavior of belugas (Delphinapterus leucas) has revealed that they regulary dive to depths of 800 meters. The deepest dive recorded of a beluga was to 1250 meters.
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