The Vanadis bristle worm, a nocturnal species native to the Mediterranean Sea, has eyes so large that if a human had them, they would need a big sturdy wheelbarrow and brawny arms to lug around the extra 100kg. This discovery marks the first time an animal group other than vertebrates, arthropods, and cephalopods has been known to have such a detailed view of the world.
The researchers, neuro and marine biologist Anders Garm from the University of Copenhagen’s Department of Biology and Lund University scientist Michael Bok, were intrigued by the worm’s large eyes and set out to investigate their visual capabilities. Their findings, published in Current Biology, revealed that the worm was able to use its eyes to see small objects and track their movements, a capability typically unique to vertebrates, arthropods, and cephalopods.
The worm’s eyesight is on a par with that of mice or rats, despite being a relatively simple organism with a minuscule brain. This discovery challenges the traditional understanding of visual capabilities in the animal kingdom and raises questions about what may have caused the species to evolve this way.