It may not have eyes, but it’s got good battery life.
© Oliver Lucanus/NiS/Minden Pictures/Corbis

Just because some animals have things like extraordinary vision doesn’t make them some kind of natural superheroes. In fact, the Kryptonite of some animals like owls, mantis shrimp and eagles might be that their other organs are weaker to compensate for their “supersight” powers.

A study conducted by researchers at Lund University in Sweden examined the Mexican cave fish, an omnivore that has no eyes and lives in dark, underwater caves where food sources are more scarce. The study claims that the loss of the cave fish’s eyes may have been a strategic way to compensate for the lack of food and energy it needs to survive.

Researchers published the results of their study on Friday in the journal Science Advances.

The study examined the biological makeup of the Mexican tetra or blind cave fish, a freshwater fish that uses sense organs called lateral lines that detect vibrations and movement in the water to show it where it’s going. Researchers also compared the cave fish to similar, surface area fish with more developed eyes that live in areas with more abundant food sources.

Researchers studied certain parts of the brain that control vision in both types of fish and calculated the oxygen consumption needed to operate a set of functional eyes. The results showed that the loss of the cave fish’s eyes saved approximately 5 percent to 15 percent of its total energy budget depending on the age of the fish, according to the study’s abstract.

Eric Warrant, a professor of functional zoology at Lund University, said in a released statement that these results may show that other animals’ bodies compensate other organ systems or functions to acquire the energy they need to operate a powerful pair of peepers and a bigger brain.

“Animals with large and well-developed eyes, necessary for their survival, pay a high price for them,” Warrant says. “As all animals have a strictly limited energy budget, a major investment in the visual system only occurs at a cost to other organ systems.”

The Mexican cave fish also may have sacrificed more than its eyes to live in such a desolate and dark environment. Damian Moran, a postdoctoral student with Lund University’s biology department who also worked on this most recent study, published a study in 2014 in the journal PLOS ONE that explained how Mexican cave fish also reduced energy output by getting rid of circadian rhythms or a “biological clock.”

This sounds like some kind of bizarre fantasy draft run by Mother Nature. So if I give up my ability to speak and form independent thoughts, does that mean I’ll gain the ability to fly?


What big eyes you have! The better to waste energy with, says new study