This image provided by the Monterey Bay Aquarium Research Institute in April 2024 shows 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 the first animals that glowed may have been coral that lived 540 million years ago. “Light signaling is one of the earliest forms of communication that we know of _ it’s very important in deep waters,” said Andrea Quattrini, a co-author of the study. (Manabu Bessho-Uehara/MBARI via AP)