HEADSCRATCHERS

Seeking answers to your science questions? Ask our resident expert, Peter Gallivan.

- Peter Gallivan

Hi, I'm Pete, and I love science and the natural world. I work with the Royal Institution (Ri) in London, where you can find exciting, hands-on science events for young people. We've teamed up with The Week Junior Science+Nature to answer your burning science questions.

Reindeer noses don't actually glow, but there are plenty of other animals in the wild that do have the ability to produce their own light, a process called bioluminescence. In most glowing animals, light is created when a molecule called luciferin reacts with oxygen. Fireflies are perhaps the most well-known bioluminescent animals, flashing a yellow, green or orange light to warn off predators, and to help find their partners in dense forests.

These glow-in-the-dark abilities are most common in fish, with 1,500 known species that can produce their own light - often those living in the dark depths of the ocean. Angler fish use a glowing orb as a lure to tempt unsuspecting prey. While most glowing animals produce their own luciferin, the Hawaiian bob-tailed squid relies on a friendly bacteria living in its skin to produce the substance. In return, the squid provides food for the microbes.