The Bottlenose Dolphin
The bottlenose dolphin is a cetacean, the cetaceans are an infraorder of eutherian mammals, (which have placenta), completely adapted to the aquatic life.
The bottlenose dolphin is the inhabitant par excellence of our seas is also present in all the oceans of the world, from coastal to temperate waters. In Italy its presence is continuous in the Ligurian Sea, in the Tyrrhenian Sea, in the Sicilian channel, until becoming the predominant species in the Adriatic, in particular in the northern part. Since the bottlenose dolphins were among the first cetaceans to be kept in captivity, they proved to be extremely adaptable to life in the dolphinariums, a large amount of data was collected on their dyadic interactions.
The ancestors of the dolphins lived and walked on the earth. From the research carried out by paleontologists it is clear that they are closely related to mammals with hooves called "ungulates". This relationship is supported by fossil records dating back to 50 million years ago. We can assume that these animals that inhabited North America, Europe and Asia, have become fit to feed on the abundant food of Tetide waters, a great sea that once stretched from the Mediterranean to beyond India , and in a short time have assumed amphibious habits.
There were rapid physiological changes for life in the waters. The thick fur has disappeared, the development of an insulating layer of fat, the ability to use eyes and kidneys with a different salt balance, the ability to see and hear underwater.
Let's analyze together what are the physical characteristics of the bottlenose today. The dolphin is a mammal, it breathes air, gives birth and suckles its puppies. The color of the body varies from a dark gray on the back up to a pinkish white on the belly. The belly is covered with a thick layer of fat. This fat has two functions: it helps to protect them from the cold and acting almost as a lubricant means that friction is not created with water during swimming. For this reason the dolphins can reach cruising speeds of 40/50 km per hour.
They live until about 30/35 years at sea, much more in a controlled environment thanks to the prevention and care of man. To date, the CITES National Forestry Association's legislation on the maintenance of these animals in captivity is very well taken care of and outlined and contributes to the correct conservation of the species.
Their body is hydrodynamic and adapted to the aquatic life. Observing it carefully, we can distinguish three types of fins: the pectoral, the caudal, the dorsal. The fins are formed of connective tissue and serve for body thermoregulation. The pectoral fins still retain inside the small bones similar to the phalanges of our fingers, a demonstration that once these animals lived and walked on the earth.
The dolphins breathe air from a single large nostril called: "breather", their nose, which is placed on top of the head called "melon". They can reach of 8/10 minutes, this of course varies depending on the depth in which they are immersed and the habitat in which they live.
Their snout is called "rostrum", it is squat and robust. The rostrum is the seat of touch and also the fins. They use these parts of the body to interact with objects or with other individuals in the herd, to probe what they want to study closely. The rostrum can be a powerful defense weapon against enemies and if it is used together with the force of the tail it can hit deadly blows.
They have about 70/80 teeth all the same and all tapered, do not use them to grab the food that is swallowed whole. Dolphins feed on: herring, cephalopods, capelin.
They clearly see both outside and inside the water. The eyes are placed laterally with respect to the head, so they have a not exactly frontal side view. In addition to this view they have an additional, highly evolved, sophisticated mechanism called "sonar or echolocation".
It is a wave called "click" that is emitted thanks to the air contained in the nasal sacs. When the wave hits the target in front of it, it forms an echo of return that provides the dolphin with the exact image of the one in front of him. The sonar has therefore an orientative and predatory function. They can orient themselves at night, in murky waters and hunt. In the hunting that takes place in the seabed the sonar is used to stun the prey that are in the sand.
They communicate with each other thanks to a wide range of sounds and whistles called bursts or whistles. The whistles are used to identify themselves in the herd, each puppy copied from birth and imitates "the signature whistle" of the mother, this allows him to locate her in the herd and will use it throughout her life. Bursts are a series of pulse sounds that are mostly used for social communication.