https://apnews.com/article/ancient-coral-glow-ocean-acb3a3e01d18cfae4fa9e44728465656

WASHINGTON (AP) — Many animals can glow in the dark. Fireflies famously blink on summer evenings. But most animals that light up are found in the depths of the ocean.

In a new study, scientists report that deep-sea corals that lived 540 million years ago may have been the first animals to glow, far earlier than previously thought.