This is termed as echelon swimming. Dolphins carry their young inside their womb and gestation is about 12 months for a bottlenose. The baby emerges tail first, and will suckle from its mother for up to 4 years. Breathing Oceanic dolphins have evolved a method of breathing without surfacing from the water. They blow a bubble when near the water surface and then quickly draw breath in when the bubble forms a bridge between the blowhole and the air, through the water.
Dolphins breathe through their blowhole located at the top of their head.
A dolphin may empty and refill its lungs in less than a fifth of second. As the dolphin breathes the air leaves the blowhole at speeds of over 100mph. To sleep, a dolphin must shut down only half of its brain, as its breathing is under voluntary control. Social Behavior Spinner dolphin's pectoral flippers are used to steer them through the water, and they also use them to stroke one another, increasing the social bond between them. Dolphins that appear to be closely bonded may swim in synchrony, twisting, turning and swimming in perfect harmony together.