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Welcome to Brainstuff, a production of IHeart Radio.

Hey, Brainstuff.

Lauren Vogelbaum here.

Animals that use their sense of sight to navigate generally have a hard time getting around without light.

So there are a lot of

adaptations out there to help. For example, owls have very large, tubular eyes that they use

to collect a lot of light. Cats have a layer of highly reflective material deep in their eyes

to give their light receptors a second chance at gathering it.

Humans have put a lot of effort into creating portable, often artificial light sources,

from torches to light bulbs and LEDs. Some bioluminescent life forms have an entirely different approach.

They make their own light and carry it around in their bodies.

Some of these animals use the light they produce the same way that people use flashlights or search lights.

But bioluminescent animals produce light very differently from the way that traditional light bulbs do.

Traditional light bulbs and fires, for that matter, create light through incandescence.

A material, like wood or a filament inside a bulb, gets very hot and emits light.

This process isn't particularly efficient, since generating enough heat to create light

wastes an enormous amount of energy. That's why LED light bulbs have become so popular. They use

what's called electro-luminoussense to basically use a low amount of electrical current to produce

photons when that current is run through certain

semiconductor substances. It produces light but wastes a lot less energy. In life

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