The extinct mammals
There are only a few dolphins of certain species left on our planet. The majority of them are extinct. For example, scientists haven't found dolphins in the river Chang Jiang and Ganges that were full of them some time ago. The fresh-water dolphins are almost at the point of extinction.
This trend is connected with the pollution of rivers, lakes, seas. They are filled with metals, pesticides, and other industrial and agricultural litter. This leads to the extinction of dolphins and the decrease of population of dolphins.
Besides, dolphins are also killed meeting motor boats and boats with propellers. Fishing with the use of fishing net, in which dolphins fall, also makes its contribution into the extinction of dolphins.
In some countries, for example in Japan, there is no policy that would forbid capturing and killing dolphins as their meat is one of delicacies. For example, the society was shocked by the recent news when hundreds of dolphins were killed so that the water became red.
The Navy Marine Mammal Program also influenced the population of dolphins. Although representatives of the navy say there is nothing to worry about, because dolphins are well protected, still dolphins may suffer a lot.
The Global warming also decreased the population of dolphins making them abandon the regular places of living and made them migrate to other seas.
So some measures should be taken to protect dolphins from severe conditions of the modern world. These mammals should be protected and people must create all possible conditions to keep animals.