Leaf Sheep, a Solar-Powered Sea Slug the Size of a Grain of Rice, Wins Invertebrate of the Year

A neon green sea slug that lives underwater and uses sunlight for energy has been crowned the winner of the Guardian’s Invertebrate of the Year 2026 competition. The leaf sheep, known scientifically as *Costasiella kuroshimae*, beat out hundreds of other spineless creatures in a global public vote. The competition, which has grown in popularity, attracted hundreds of thousands of readers worldwide. These voters cast their ballots to celebrate the animals that make up the majority of life on Earth. The leaf sheep’s victory was secured after readers read about and shared their appreciation for the tiny creature. The leaf sheep is notable not only for its bright color but also for its unique ability. It is a solar-powered slug, a trait that has inspired at least one Pokémon character. Despite its small size—comparable to a grain of rice—it has captured global attention. The top 10 shortlist for the competition is available to view, and naturalist Chris Packham has highlighted the importance of such creatures, noting that life as we know it depends on invertebrates.