In our article we will talk about the Irrawaddy dolphin. We will talk about where he lives, what he looks like. The topic of the disappearance of this large mammal will also be touched upon. Note that wildlife fund workers are concerned about the very rapid decline in the population. The number of these mammals has decreased to a critical level.
These dolphins are sacred animals in Cambodia and Laos. But even despite this, in these countries they are becoming less and less. Experts explain this fact by the fact that young dolphins simply do not live to adulthood, and old individuals die. As a result, there is no one to continue the race of these smart animals.
Description and photo
The Irrawaddy dolphin is an aquatic mammal. It belongs to the genus Orcaella in the dolphin family. A representative of this species of mammal has a long, flexible neck that moves in different directions. These dolphins, unlike their other relatives, lack a beak. They also have a different dorsal fin. It is small in size, closer to the tail.
The color of the Irrawaddy dolphin is blue-gray. In the lower part of the body is a lighter shade. The length of an adult mammal can reach 2.5 meters. The maximum mass of the Irrawaddy dolphin is 150 kilograms. A newborn cub weighs twelve kilograms. At the same time, the length of his body is not more than 1 meter.
Habitat
Where does the Irrawaddy dolphin live? These animals can live in both sea and fresh water. Although some populations choose the second option for life. They live in the fresh waters of the Mahakam, Mekong and Irrawaddy rivers. Such a mammal also lives in the coastal sea waters of Southeast Asia. Based on habitats, biologists divided this species into two subspecies - freshwater and, of course, marine.
Behavior
These dolphins live in groups of three to six individuals. Adult mammals can safely move from one group to another. Note that usually this behavior is not typical for dolphins, they are wary of strangers.
In the process of exploring territories, this animal raises its head out of the water. The dolphin, thanks to its flexible neck, rotates it in order to see everything that surrounds it. If we talk about the swimming speed of a mammal, then it is quite low. When a dolphin emerges from the water in order to swallow air, it exposes only the upper part of its head, and not all, like many other species of cetaceans. Therefore, these mammals are not so easy to see in the wild. Inhale doesIrrawaddy dolphin fast. Only 14% of all dives involve splashing.
Relationship with a person
These marine inhabitants are friendly to humans. They accompany the fishermen's boats. In addition, dolphins help drive fish into nets. Moreover, it has been noticed that these mammals quickly remember the places where people put them. After that, the dolphins consciously drive schools of fish into the net. Previously, almost all fishing villages in the Indonesian archipelago had their own “local” flock of dolphins. It was they who drove the catch directly to the nets. It was funny that sometimes the inhabitants of different villages sued the neighbors if they lured their flock to their plot.
Why did the population decrease?
However, the Irrawaddy dolphins were killed by net fishing. The thing is that all members of the group, from cubs to adults, took part in the corrals. And the former, unlike the latter, could not stop in time, got entangled in nets and died. There is information that in the middle of the twentieth century, the infant mortality of such dolphins reached sixty percent. And after the inhabitants of the region switched to trawl fishing, it generally became a disaster for these animals. Then the mortality of cubs in some regions increased from 60 to 80%.
Also, do not discount water pollution from fields that contain toxic substances for animals. For example, high concentrations of mercury were found in some tissue samples from dead dolphins.
