A species of fish living in perpetual darkness with no eyes has changed its skull structure to help it survive. Researchers from the University of Cincinnati have studied how cavefish (Astyanax mexicanus) living more than hundreds of feet below the ground has increased its sensory system to adapt to the harsh environment.
Scans revealed that the skull of the fish is asymmetrical and slightly bent to the left. This allows the fish to constantly swim in an anti-clockwise direction along the edges of the cave and find food.
Mexican cavefish are born with eyes but they slowly shrink and are completely lost in adults.
Fat deposits are stored in the empty eye sockets and covered with scales. Researchers are planning to study this adaptation and regressive evolution (evolution by losing certain abilities or traits).
