31/01/2026
The eastern emerald elysia (Elysia chlorotica) is one of the most unusual animals ever studied. Rather than producing its own energy like most animals, it steals chloroplasts from the algae it eats and keeps them alive inside its body. These borrowed chloroplasts allow the sea slug to harness sunlight and produce energy, a process known as kleptoplasty. Thanks to this adaptation, it can survive for months without feeding, relying largely on sunlight instead. Its vivid green colour is a result of these chloroplasts and also acts as natural camouflage among sea plants. While the slug itself is not a plant, it remains the first known animal discovered to sustain itself using photosynthesis-derived energy in this way, a striking example of how flexible life can be.
