You've heard of animals that can lose and then regenerate a tail or limb. But scientists reporting in the journal Current Biology on March 8 have now discovered two species of sacoglossan sea slug that can do even better, shedding and then regenerating a whole new body complete with the heart and other internal organs. The researchers also suggest that the slugs may use the photosynthetic ability of chloroplasts they incorporate from the algae in their diet to survive long enough for regeneration.