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Bottlenose Dolphins

Bottlenose dolphins are powerful swimmers and travel at about 5km/hour. When in coastal waters, dives rarely last more than 3-4 minutes, but oceanic animals can dive to depths of 600m for 15 minutes. When they come up to the surface, their head is shown but not their beak. Dolphins are conscious breathers, this means that they have to be awake or semi-conscious to breathe or else they will drown. So they sleep in a semi-conscious state at the surface with their blowhole exposed and only a few minutes at a time. Due to this they are able to rest one half of their brain whilst the other part is alert for approaching danger, and then are able to switch which side, while they are resting.