Leaf Sheep: Solar-Powered Sea Slug That Photosynthesizes
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- Costasiella kuroshimae (the leaf sheep) performs kleptoplasty, stealing intact chloroplasts from algae and storing them inside leaf-like cerata on its back that act as solar panels, enabling photosynthesis.
- The rice-grain-sized slug grazes on Avrainvillea algae in shallow tropical reefs around Japan, Indonesia, and the Philippines, where its vivid green cerata double as chemical defenses and camouflage.
- Two rhinophores above its eyes serve as sense and taste receptors, helping the leaf sheep locate algae, which it does without leaving its food source.
- Science only described the leaf sheep in 1993; advances in underwater and macro photography have since propelled it to viral popularity, with readers comparing its looks to Shaun the Sheep and the Pokémon Shaymin.
- The Guardian is running its invertebrate of the year series from August 3–12, profiling reader-nominated species ahead of a public vote, and the leaf sheep is an early favorite for the 2026 title.
Why it matters: The leaf sheep is one of the few animals known to perform kleptoplasty, harvesting functional chloroplasts from algae to generate energy from sunlight — a trait that makes it a standout teaching example of cross-kingdom biological ingenuity and a near-certain frontrunner in the Guardian's 2026 invertebrate poll, where broader public recognition could boost marine invertebrate conservation attention.
