Sharks are color blind
At the University of Queensland examined the eyes of the shark and came to the conclusion that those deprived of color vision.
The research object of scientists were 17 species of sharks. During microspectrophotometric analysis, it was found that 10 of them were no cones, intended for color vision, and their role was partially assumed the highly sensitive sticks. The remaining seven species that belong to three different families, had one type of sensing elements designed to detect wavelengths from 532 to 561 nm.
It is known that whales, dolphins and killer whales also stick with the cones of one type, which is able to recognize green color.
With regard to the research results, here we can conclude that, apparently, for the sharks plays a major role contrast, which allocates a single object on a background of another, — says biologist Nathan Scott HART.
The information obtained will be used for development of equipment for divers and surfers.
Added to category: Fauna
Sharks scare off patrols of dolphins and orcas
Scientists from Australia, South Africa, Japan and New Zealand are working to establish patrols of dolphins and orcas that can protect coastal areas from shark.
The idea to organize dolphins, sort of, marine coastal patrols appeared biologists on the basis of a very common phenomenon, when these marine mammals protect the troubled people from predatory marine fish.
In particular, one of the most famous cases of recent years was the story that happened off the coast of New Zealand, where a group of 4 divers for no apparent reason surrounded by a dense ring of dolphins. Thus animals persistently thwarted any attempts of people to escape from a cordon. When one of the divers still managed to leave the circle, he saw that around the great white shark. As a result the dolphins escorted the people to a safe shallow water.
At the moment one of the main problems that scientists are trying to solve is to find a way to “bind” the dolphins to a certain area, as in ordinary life, they moved in search of the best places for reproduction.
Added to category: Fauna
Female sharks can reproduce without the participation of males
Reproduction in nature is female, no male is known as parthenogenesis. While the adult organism develops from an egg that was not fertilized. This phenomenon is quite rare, and scientists were able to trace only about 70 species of vertebrates, including fish, lizards and birds.
To closely examine this phenomenon of sharks scientists have pushed the case in the aquarium Belle Isle in Detroit, where in 2001 the female bamboo sharks, which never met with males, there was a baby. Was an isolated case, so to confirm this ability of sharks took another few years of research.
During his scientific work, biologists have managed to grow from two eggs to two healthy cubs bamboo sharks, the observation of which lasted for five years. According to scientists, the structure and evolution of no abnormalities in individuals born from unfertilized eggs, compared with sharks, which appeared when the participation of males, no.