The ways of food during the evolution have undergone profound changes, found chiefly in the mouth region.
The teeth, in principle differentiated, has evolved into teeth not differentiated and with the permanent dentition only in odontocetes.
The Mysticeti instead replaced the teeth with special corneas structures suitable for the filtration: the baleen.
The most delicate phases in the life of the animals are breeding and the birth of children. The reproduction of cetaceans is usually preceded by long courtships often find that the males engaged in fighting to win the female.
The courtship is intended solely for coupling: once the sexual act males and females are divided definitely continuing its independent life.
Males, generally larger, are characterized by a genital and anal fissure in females are also the mammary fissures.
A fundamental characteristic of Cetacea, Odontoceti in particular, is the ability to use sound waves to locate objects. A bottlenose dolphin in complete darkness is able to detect a small ball with a diameter of 2 cm at a distance of more than 72 meters. The efficiency of echolocation allows dolphins, even in the dark, to pick and choose their prey more acceptable.
The numerous adaptations to aquatic life have developed in cetaceans, more than any other marine mammal, the capacity to perform prolonged skin diving. In fact they are capable of reaching great depths thanks to some physical and biological adaptations. Small cetaceans, such as striped dolphin and bottlenose dolphin, diving can take about 10 minutes to a depth of 200 meters. The pilot whales can reach 15 minutes of apnea and a depth of 500 meters. But the absolute record holder of immersion is the sperm whale, which can reach depths up to 3,000 meters with apnea that lasts up to two hours or more. The divers qualities do not arise, however, the large size of the lungs, which retain the same proportions of terrestrial mammals. Derive rather from the amount of respiratory pigments in the blood and muscles.
For more details please visit the library where you can buy the book Dolphins and whales in Italy.