I remember several happy Sabbath evenings when, after our traditional Sabbath walk, I would run around in the front yard just after sunset and try to catch fireflies—those elusive light dancers that always managed to be just out of reach of my chubby little fingers. My dad always told me that if I could catch a jar full, they could light up my room at night with their eerie, luminescent glow.

At the time, I didn’t understand what made the fireflies flash. Where does that light come from? The answer is fascinating.

The firefly’s form of light is called bioluminescence, the emission of light by living organisms, like fireflies or deep sea fish. Most bioluminescent organisms live in the deep sea—in an environment that is practically devoid of light. Many of them manufacture their own light within their bodies and use that luminescent glow for different purposes.

In its most basic form, the process of bioluminescence involves the combination of two different chemicals: a luciferin, a light-producing substance; and a luciferase, an enzyme catalyst. A chemical reaction occurs between these two kinds of chemicals, and a byproduct of that reaction is the glowing light we see. Some deep-sea creatures have bioluminescent growths or patches on their bodies, and others have light organs to house bioluminescent bacteria.

These luminescent life forms can use the light that they produce the same way we might use a flashlight—to illuminate our surroundings. But how they produce that light is very different from how it is produced by the light bulb of a flashlight. The light in a light bulb is created through incandescence: The filament inside the light bulb gets hot, and that heat creates light. Bioluminescent creatures like fireflies and glowing deep-sea fish create a different kind of light. Whereas the light produced by a light bulb is hot light, the light produced by bioluminescence is cold.

Think of a glow stick or a glow bracelet. When you crack a glow stick, it starts to glow as the substances within it combine, react and make light. But have you noticed that no matter how brightly it glows, a glow bracelet never gets hot? That is because the light produced by this chemical reaction neither requires nor generates heat.

Bioluminescence has many different functions in the lives of these luminescent organisms. In each species, this living light helps it interact with its environment in a different way.

Fireflies—one of the few land-based bioluminescent species—use their living light for communication. Those seemingly random flashes that I used to chase as a child are actually a very specific pattern. Each species has its own pattern, and the males flash their specific patterns in order to attract a mate.

One deep-sea fish, the angler fish, uses bioluminescence to attract its prey. This fascinatingly ugly fish has a large head, long, sharp teeth, and a long growth on the top of its head called a filament. At the end of the filament is a ball of luminescent material that the fish can light up to attract other fish. When the fish see the ball of light in the otherwise pitch-black darkness of the deep sea, they are fascinated by it, coming closer and closer until the angler fish snatches them into its jaws.

Red light doesn’t travel far in the deep ocean, and many deep-water fish and other organisms cannot see it. One species of loosejaw fish uses this to its advantage—it produces red light to illuminate its surroundings. This allows the fish to be invisible to its prey while simultaneously illuminating the surrounding water and allowing it to see its prey more easily.

Another strategy of bioluminescent organisms is counterillumination, which some sea creatures use to protect themselves. Sharks and other predators usually hunt from below, spying their prey above them as it is outlined against the lighter water above. To counteract this, some species produce spots of light on the undersides of their bodies, which camouflage them from predators below by helping them blend in with the lighter water above them.

The hatchetfish uses this strategy. Hatchetfish have light-producing organs on the underside of their bodies, and they can adjust the amount of light that comes from these organs to match the light that comes from above—making them practically invisible to predators looking up.

Several bioluminescent organisms use their light as a distraction or as a form of self-defense. The brittle star can distract predators with its bioluminescent abilities; when predators approach, the brittle star will detach a glowing part of one of its arms and crawl away while the predator is distracted by the glow. In a similar manner, some species of sea cucumber will detach bioluminescent material onto fish that may be swimming nearby, and then the predators will follow the glowing fish and leave the sea cucumber alone.

Certain species of squid also have the ability to flash when they are threatened, startling approaching predators. While the predator is disoriented, the squid can escape.

The vampire squid uses defensive luminescence as well. Instead of releasing ink when threatened—as squid closer to the surface of the ocean often do—the vampire squid instead releases a luminous mucus into the water. This material is sticky, and it can disorient and delay predators long enough for the squid to swim away.

Bioluminescence is a truly astounding process. It allows creatures in the deepest, darkest places of the Earth to create light of their own. The great detail in the creation of each of these creatures—and even in the creation of the process of bioluminescence itself—shows the fingerprints of God and the incredible creative power of His mind. How could something so intricate as a bioluminescent organism have evolved by itself, simply by chance?

There is so much variety in God’s creation—so many marvelous natural wonders that we can learn about. They deepen our understanding of the natural world while deepening our awe in the power of the great Creator God—whether it is the flash of the common firefly in your backyard or the glow of the angler fish hundreds of feet below sea level.

These creatures of living light are truly amazing to study. So the next time you see a firefly’s light, stop for a moment and meditate on this amazing creation: the power of living light.