A worm with a view: the animal with eyes 20 times the weight of its head

Scientists from the University of Copenhagen and Lund University have described the vision of a worm with eyes that are around 20 times the weight of its head.

Writing in Current Biology, researchers explored why the Vanadis bristle worm has evolved to have eyesight that is equivalent to much larger animals such as mice or rats.

Research has demonstrated that the worms, which are found on the Italian island of Ponza, are able to see small objects and track their movements.

Michael Bok, of Lund University, highlighted: “Together, we set out to unravel the mystery of why a nearly invisible, transparent worm that feeds in the dead of night has evolved to acquire enormous eyes.”

Anders Garm, of University of Copenhagen, shared that the worms have “outstanding vision.”

“Its eyesight is on a par with that of mice or rats, despite being a relatively simple organism with a miniscule brain,” he said.

Garm shared that one theory behind why the worms evolved to have such large eyes, is that the worms themselves are bioluminescent and communicate with each other through light.

“If you use normal blue or green light as bioluminescence, you also risk attracting predators. But if instead, the worm uses UV light, it will remain invisible to animals other than those of its own species. Therefore, our hypothesis is that they've developed sharp UV vision so as to have a secret language related to mating,” he said.