Bioluminescence is a process wherein light is produced by a chemical reaction within a living organism hence the name. Bioluminescence is a "cold light." and it means less than 20% of the light generates thermal radiation or heat. Some species use this to confuse or startle their predators just like how a vampire squid does it. They lack ink sacs unlike other squid species and as a defense mechanism or escaping tactic, they eject sticky bioluminescent mucus, which can startle, confuse, and delay predators, allowing the squid to escape. Bioluminescent light’s appearance varies greatly and that also depends on the habitat and organism in which it is found. Most marine bioluminescence is expressed in the blue-green part of the visible light spectrum. In the deeper part of the ocean, these colors become infinitely more visible. Land organisms, on the other hand, glow in the yellow spectrum and this includes yellow like fireflies. Bioluminescence is also used by living organisms to hunt prey, as a defense mechanism against their predators, find mates during mating season, and execute other vital activities. For an organism to have this characteristic, a chemical reaction that results in bioluminescence requires two unique chemicals and those are luciferin and either luciferase or photoprotein. Luciferin is the compound that actually produces light. When found in a chemical reaction, luciferin is the substrate. The bioluminescent color (yellow in fireflies, greenish in lanternfish) is a result of the arrangement of luciferin molecules. Some bioluminescent animals, like brittle stars, have a way to detach body parts to distract their predators. The predator follows the glowing arm of the brittle stars, the rest escapes and crawls away from the enemy. Some use this as an offensive strategy and they usually use it to lure or search for their prey. Anglerfish are those who use this to lure their prey. This fish species has a huge head, sharp teeth, and a long, thin, fleshy growth (called a filament) on the top of its head which they use as bait. They light this up and smaller fishes come close to it out of curiosity. Once ready, anglerfish snap their prey. At night in the woods, we can also see this spectacular phenomenon. Just like adult fireflies, also called lightning bugs, they also emit light. They use this not just to amaze us but to attract mates. Although both male and female fireflies can have this characteristic, in North America, most flashing fireflies