Dolphins Adapted to Life in WaterWater provides more support than air but is more difficult to move though; dolphins are beautifully streamlined to slip though water.
Hunting in packsDolphins are toothed whales and use their peg-like teeth to capture squid and fish, which they swallow whole. They hunt in packs and synchronously leap out of the water, take a breath and scan the horizon for fishing birds. When they locate a shoal they drive the fish into a ball, then swim underneath and force the fish to the surface where they cannot escape. Then the feeding frenzy begins and sharks, seals, predatory fish and birds join in.
Dolphins are very sociable and communicate using clicks and squeaks and are able to hear six times the sound range of the human ear, although they have no external ear but and auditory meatus opening. They navigate using echolocation. They emit high-pitched sounds that bounce off obstacles ahead, allowing them to identify objects and food with remarkable accuracy and speed.
After a courtship of fondling and aerobatics, dolphins mate underwater. The gestation period is 8-16 months depending on the species. A single calf is born, usually tail first and is nudged to the surface to take its first breath of air. The calf cannot suck underwater and so the mother pumps rich milk from her teat into its mouth.
Dangers from Pesticides
Predatory mammals at the top of the food chain are particularly susceptible to pollutants and pesticides that are concentrated up the food chain. It is important to keep reviers and the sea free from pollutants. DDT stored in the blubbler and milk of dolphins during the years while they mature can be off-loaded, in potentially leathal concentrations, in the milk suckled by the first-born calves.
If a dolphin is stranded on the beach, try to keep it calm, cool and shaded. Make sure it is lying on its belly and dig holes for its fins. Cover it with wet towels and pour water over it but do not get water into the blow hole or it will drown. Contact the authorities immediatly. Keep quiet and restrict movement around the dolphin.