India, June 7 -- T his tiny sea slug - each one about the size of a grain of rice - was discovered near Japan in 1993 and is one of the only animals in the world capable of photosynthesis. It cannot by itself turn sunlight into food. But it can steal chloroplasts from algae, which it then uses to turn sunlight into energy, whenever algae itself becomes scarce. The leaf sheep (Costasiella kuroshimae) gets its name from the fact that it grazes in ways that keep algal levels balanced in marine water bodies. This advanced, highly specialised species lives in intertidal zones near coral reefs in Japan, Indonesia and the Philippines. The stolen chloroplasts also give it its green, leafy appearance, which helps it blend into the algae too, camoufl...