They swim at speeds of approximately 12 miles per hour. Males fight viciously over females during the breeding season, and a hierarchy based on size is generally established in a group of males. The beginning of the brief pair bond takes place when the male shows a preference for the swimming company of a particular female and remains with her for prolonged periods of time. 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.