Book 6, Question 31
Why Can Some Fish Glow?
Some deep-sea fish make light inside their bodies with a chemical reaction. Others host glowing bacteria that live on them. The light is a tool for finding food, friends, or escape.
From the book
Page from A Million Whys Book 6
More fun facts
- About 1,500 kinds of fish can make their own light. This is called bioluminescence.
- Glowing has evolved in fish 27 separate times, and 17 of those involve teaming up with glowing bacteria.
- Flashlight fish keep glowing bacteria in special pouches below their eyes.
- Flashlight fish use their light to stay together in a school even when it is almost totally dark.
- Deep-sea fish may use their glow like ID badges, to recognize others of their own kind.
- Some reef fish glow in many different colors and patterns, which may help them send messages.
Sources: National Geographic, National Geographic, BBC
Questions kids ask
What is bioluminescence?
It is when a living thing makes its own light.