Evolution has helped creatures adapt and exist in different environments. Taking the example of microbes that live in oceans that have gradually evolved into bugs, but in the case of the Mexican cavefish, evolution has led to its blindness. Many parts of its brain have also evolved in a manner that turns it into an insomniac. A Greater number of teeth, increased jaw size, and better taste buds are the upsides of the evolution of these blind cavefish.
The question that intrigued a group of scientists from the University of Cincinnati is that how do these little blind cavefishes navigate their way and look for food. Their study reveals that the answer might as well lie in their bones. According to R&D, this breed of cavefish is generally found in the limestone caves of Mexico's rainforests. Mostly, these are surface dwelling fishes that can be found in rivers and creeks.
An interesting fact is that cavefishes could see when they were born. With time, in place of their eyeballs, there is deposition of fat that completely obscures their vision. In order to adapt to the changing environment, blind cavefish have developed enhanced sensory systems. Also, their skull structure and metabolism system have evolved. The researchers believe that it is due to the asymmetrical design of the skull and sensory system that these fish can find their way and get food
Symmetry is a common feature in most animals including fish. Scientists have been researching these fish for years and their hypotheses are that it is their symmetrical body structure which makes visual perception easier on their brains. As these fish mature, a part of their skull skews to the left due to fusion and fragmentation of some of the bones below their eyes, says Phys.org. These cavefish has 'neuromasts' which are unique sensory organs that assist them in finding their way and also cause them to swim in a clockwise pattern.
A surprising fact is that the blind cavefishes are not only surviving but they have made darkness of deep cisterns of the rivers their way of life. There are many questions still unanswered about these fishes. Biologists are working towards finding the DNA of cavefishes to get more clarity about their regressive evolution, navigation and food procuring patterns.