Humpback whales are constantly falling into the mess because of bad vision

Humpback whales

Photo: American Cetacean Society

Clashing with boats and confusion in the nets are one of the main causes of the death of humpback whales found in almost all oceans from Arctic to Antarctic.

In a new one study Scientists were able to explain why these animals are so vulnerable – they have extremely weak vision, writes The New York Times.

Although the eyes of humpback whales and the size of a baseball ball, they actually give animals a very limited vision of the environment.

According to the researcher Jacob Bolyn, Gorbachi see the world mainly in the form of shadows and do not distinguish small details until they float close.

This means that the thin lines of fishing nets or outlines of boats animals may simply not notice – until it is too late.

That scientists have learned about Gorbachev

The team of scientists studied the eye of a young humpback whale that died on the North Carolina coast in 2011. It managed to eutanasize on land, which gave scientists the opportunity to explore a relatively preserved body.

Despite the large size of the eyes, more than a third of their depth is occupied by sclera – a dense part of the eye that does not participate in the vision.

But the main limit was the low density of the ganglion cells of the retina (a kind of « pixels » that transmit brain images) – only about 180 per square millimeter.

For comparison, people can have up to 40 thousand ganglion cells, in predatory birds – up to 70 thousand. Their number depends on the « resolution » of vision.

Researchers modeled the whale sees a net or a fish shoal, and it turned out that these objects resemble blurred silhouettes. Moreover, the humpback whales see only in the black and white spectrum.

Some scholars suggest that the real whale vision is worse. The Spanish biologist Elena Vesino Corder says that in her studies in other types of whales of cells on the retina was even smaller.

But how do whales are oriented in the ocean? Biologists suggest that in the world without nets and motor boats they just did not need sharp vision.

Humpback whales do not have natural enemies, do not use echolocation, like others similar, and probably seek prey with the help of smell.

« We are so fond of whale songs and sonaar that we know almost nothing about the purpose of their huge eyes »– says Professor of Biology of Duke Zenke Jonesen University, one of the authors of the study.

Research Posted In Proceedings of the Royal Society B. The authors hope that understanding the visual restrictions of whales will help to create a more noticeable fishing equipment for them and reduce mortality from interaction with man.

We will remind, earlier scientists told about the secrets of survival
the oldest humpback whale in the world
Old Timer.