The most common species of Dolphin encountered at the Reef is the spinner dolphin, named because of the aerial behaviours they perform when leaping out of the water. These small dolphins will often ride the pressure wave off the bow of slow moving vessels.
Dolphins belong to the cetacean group, which includes their larger relatives, the whales. Dolphins are basically toothed whales, and as such, are grouped with pilot and sperm whales, as opposed to the baleen group (Humpbacks), which have straining plates to sieve plankton.
Dolphins evolved from mammals, and have perfected a streamline body extremely efficient for movement through the water. Their tails are horizontal (as opposed to vertical in fishes), and lack any bone support, and through a series of tendons are able to produce powerful strokes to move through the ocean. Dolphins can dive deep, but need to surface every few minutes to breathe.
Dolphins form large groups called pods, and there is a strict social hierarchy within the group. Some female dolphins will assist in midwife duties, and mourn with families when a member dies. Adults will attempt to deter predators such as sharks away from the pods, and diligently defend their babies.