Blind Cavefish Not So Blind After All By Charles Q. Choi, Live Science, Fox News
Blind cavefish whose eyes have withered away may not be so blind after all.
Instead, a light-sensitive organ in their brains can detect light, research now reveals.
The blind cave-dwelling form of the Mexican tetra (Astyanax mexicanus) evolved from surface-dwelling ancestors whose eyes degenerated after the fish shifted their habitat into complete darkness a million or more years ago.
These albino cavefish dwell today in freshwater caves in northeastern Mexico, with skin growing over their now useless eyes.