The male often postures in front of the female with his back arched and also strokes, rubs, and nuzzles her. Mouthing, jaw clapping and yelping are also part of precopulatory behavior. Courtship can sometimes be rather violent, with male and female bumping heads forcefully. Tursiops truncatus displays a wide variety of vocalizations and is hypothesized to have a complex language that people may eventually be able to use to communicate meaningfully with dolphins. Each dolphin appears to have its own distinctive whistle by which it communicates a limited amount of information on its identity, location, and condition to other dolphins.
Dolphins also use clicklike pulses produced by nasal sacs in the forehead for echolocation.
From the time of the early Greeks, it has often been claimed that dolphins will save humans from drowning or from shark attacks, although concrete evidence for these claims have not been found. Dolphins will support members of their own kind at the surface of the water however, to permit them to breathe when they are in distress. The bottlenose dolphin is fond of warm, shallow inshore waters. They are commonly seen in bays and lagoons, and sometimes ascend large rivers. In certain areas it ranges as far offshore as the edge of the continental shelf.