Bioluminescence in the sea whip coral Funiculina sp. observed under red light in a laboratory. Most animals that light up are found in the depths of the ocean and they might have been doing it longer than thought. In a study published in the journal Proceedings of the Royal Society B on Tuesday, April 23, 2024, scientists report that deep-sea corals that lived 540 million years ago may have been the first animals to glow.