The only lake on the planet where sharks live

In the Republic of Nicaragua there is a lake of the same name, which is separated from the ocean by a small strip of land several tens of kilometers. Its area exceeds 8 thousand square kilometers, and it is the largest lake in Latin America. But its peculiarity is not in size, but in its inhabitants - it is the only freshwater lake on our planet where sharks live quite comfortably.

Nicaraguan sharks were considered endemic for a long time, however, in the middle of the 20th century, when research became more detailed, scientists found that blunt-nosed sharks live in the lake, the same ones that swim in many warm seas. They are also called bull sharks. But where did such dangerous predators come from in a freshwater lake?

So another theory appeared, but again erroneous. Nicaragua is very close to the ocean coast, so it was very likely that it used to be a Pacific Gulf. However, another fact later emerged: bull sharks are very tolerant of fresh water and may well swim in coastal waters. Therefore, they swim in the swift San Juan River, on which they get to Lake Nicaragua. Later, biologists found out the duration of such a trip: in general, sharks overcome this distance in a week and a half.

By the way, these are not the only animals that, in theory, should not live in the lake: for example, tarpon and sawfish, which belong to brackish-water species of fish, still live here.

Watch the video: Bull Sharks Upriver. National Geographic (April 2024).