A research led by Sweden’s Lund University has unveiled that large eyes are developed at the cost of other body organs. To have big eyes in an infant, total energy between 5 and 15% is used. The researchers have reached at the conclusion by studying a Mexican cavefish, which has lost its visual system through regression.

The research observed the fish that lives in dark, nutrient-deficient environment and has no use for eyes. However, such is not the case for surface-dwelling variant, known as morph. One of the researchers, Eric Warrant, said that large and well-developed eyes animal has to pay a high price. It has been said so as species have limited energy capacity.

The researchers said, “Over evolution, this morph lost both eyes and visual cortex, without a doubt because of the unsustainable energy cost of maintaining a sensory system that no longer had any significance”.

An animal living in permanent darkness and does not require vision to search out for food or avoid predators would really have to require eyes or visual centers in the brain.