(c) Geek prime
This creature right here is quite astonishing!
Meet the eastern emerald Elysia or Elysia Chlorotica, a sea slug that seems to have the genes like the algae it eats, so that it can produce energy from sunlight just like plants.
Sea slug is a common name for some marine invertebrates that more or less resemble terrestrial slugs. This one, in particular, has incorporated genes from algae into its own chromosomes enabling it to photosynthesis.
That means the slug can become solar powered, using the sun's energy to turn carbon dioxide and water into the nutrients it needs to survive.
A young Elysia Chlorotica is reddish or grayish in colour. When the slug starts feeding it becomes bright green because of the chloroplasts in the cells. Since the slug does not have a shell to protect itself from predators, the green colour helps to camouflage it and blend with its surroundings thus increasing its survival.
An Elysia Chlorotica can live off photosynthesis without feeding for up to a year. By spending less energy on activities such as finding food, the slugs can invest this precious energy into other important activities allowing them to longer.