Dolphins are marine mammals that are closely related to whales. There are almost forty species. They vary in size from 1.2 m and 40 kg, up to 9.5 m and 10 tones. They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid. Dolphins are among the most intelligent animals and their often friendly appearance and seem playful attitude have made them popular in human culture. The tongue of the dolphins can take on “corrugated”, which allows to prevent suckling offspring milk is mixed with salt water.
The dolphins are relatively close to shore and often interact with humans. These mammals are totally adapted to live in the aquatic environment where they find their food and can remain submerged for long periods of time. Like other whales, dolphins use sound to communicate, navigate and reach their prey. For them it is important echolocation.
Communication is fantastic that these animals may have with the human being, of this special relationship arises the dolphin, with which it is now possible to treat children with mental and sensory disorders, as well as people in addiction rehabilitation periods such as alcohol or drugs.

NATURAL SELECTION

Over-production: The gestation period varies by species, but is usually between ten to twelve months.
When the female will give birth, we can see that its swimming is slower and often accompany other females to avoid attacks by sharks or other predators.

Struggle for Existence: The dolphins don’t usually compete between them, this is because these animals are very friendly, and they never leave a mate which is ill or hurted, they always try to help it by going to the surface or to somewhere that is safe. Furthermore, they often are grouped because by this form they are protected from predators, such as sharks.
Survival of the fittest: The dolphin that swims better and fastest, will be the one which survived more time.

Variation: What has changed more in the dolphin’s physical shape is its form of the nose. Before some types of dolphins had its nose flattened and more rounded, however now their nose is larger.

Advantageous characteristics are passed on to offspring: One good characteristic is their hydrodynamic bodies that they have to move very well through water.

Advertisements