Bioluminescence is a natural phenomenon that highlights the brilliance of the natural world—literally! Glowworms light up, fireflies flash and plankton sparkle. These animals use their natural abilities to ensnare prey, to defend themselves, to attract mates and, at times, to simply illuminate the path ahead.
During Natural Habitat Adventures’ trips to Southern Australia and Tasmania, New Zealand, Mexico and Costa Rica, bioluminescent animals and out-of-this-world locations seldom fail to impress.
What Is Bioluminescence?
Bioluminescence is produced by a chemical reaction within a living organism. This reaction requires two unique chemicals: luciferin (the compound that actually produces the light) and either luciferase or photoprotein. While some bioluminescent organisms produce luciferin on their own, others absorb it through other organisms, either as food or in a symbiotic relationship.
The specific bioluminescent color is a result of the arrangement of luciferin molecules and usually depends on the habitat and organism in which it is found. Most marine animals, for example, glow blue-green. Many land organisms also exhibit blue-green bioluminescence, though others, such as fireflies, emit light in the yellow spectrum. (Fun fact: Fireflies can be found on every continent except Antarctica!)
People often confuse bioluminescence and fluorescence. (Think: the ink in a highlighter marker.) The difference? Florescence doesn’t involve a chemical reaction; instead, a stimulating light is absorbed and then re-emitted. Florescent light is only visible in the presence of the stimulating light. Glow-in-the-dark products like stickers and glow sticks rely on phosphorescence. This is similar to florescence, but phosphorescent light is able to re-emit light for longer periods of time.
The National Oceanic and Atmosphere Administration estimates that 80% of ocean-dwelling organisms in the pelagic zone (656 to 3,280 feet deep) are bioluminescent. Jellyfish, eels, octopuses, giant whale sharks and even some sea turtles fall into this category.
Deep in the ocean twilight zone beyond sunlight, female barbeled dragonfish use a bioluminescent lure attached to their chin as bait. Closer to the surface, bioluminescent plankton set the sea aglow when the conditions are just right, making a stir of stars at the surface after the sun goes down.
On land, one species of glowworm hangs from the foliage of the forest’s canopy, shimmering against the night sky. Another glows in the depths of darkness underground in the caverns of ancient caves amid stalagmites and bedrock streams.
3 Places to See Bioluminescent Animals on Nat Hab Adventures
1. Tasmania, Australia
Nat Hab’s Australia South: Tasmania, Kangaroo Island & the Great Ocean Road adventure takes nature lovers far from the beaten path. This trip alternates between exotic islands where we search for koalas and kangaroos, wildlife reserves where tours stop to learn about the Maori culture and the creatures that call the area home, and cave systems that take on a life of their own.
During the Tasmania part of the trip, we stop at Marakoopa Cave in Mole Creek Karst National Park. Crystals and stalagmites accompany reflection pools and underground streams here. The may seem barren, but these caves are far from uninhabited, as evidenced by the bioluminescent glowworms that illuminate the darkness above.
The cave’s acoustics are another fascinating feature. It is said that tunes sung out have perfect clarity, carrying across the cavern in perfect pitch.
2. New Zealand
On our New Zealand Nature Explorer tour, we visit islands where effective conservation practices protect rare species no longer found elsewhere and spend days amid fur seals and dolphins close to the water’s edge. Inland, we venture towards mountain peaks, where hidden alpine lakes await at the end of rewarding hikes.
Also on the itinerary is time spent exploring the Te Wahipounamu World Heritage Area on the South Island. During the day we scout for the resident Fiordland crested penguin (also known as tawaki). The species can’t be found in any other place on Earth except the South Island, and Lake Moeraki is home to about 10% of the entire population.
After sunset, we set off in search of dazzling stars while hiking along the shores of Lake Moeraki. Like their cave-dwelling Australian counterparts, glowworms bring out the untouched beauty of the lake and forest. Hanging from the ancient trees along the route, their soft glow is meant to attract prey.
The World Heritage Area is the result of a passionate campaign by the owners of the Wilderness Lodge Lake Moeraki. We stay at the lodge and are led to the area’s highlights by the naturalist guides trained by Dr. Gerry McSweeney. He and his wife, Anne Saunders, successfully lobbied for the reserve by showing how conservation tourism benefits the community more than destructive logging.
3. Costa Rica
Further south, you can choose your own adventure on a private Costa Rica itinerary. The country’s amazing cloud forests and jungles, its miles of coastline, and its culture-packed cities are all within reach.
A highlight for many is a nighttime kayak ride off the shores of Isla Chiquita to witness the spectacle of starlight in the sea. The location has the right combination of temperature, bioluminescent plankton and isolation/lack of light pollution for the light to stand out in the dark waters below. The microscopic organisms glow when disturbed as a defense mechanism against larger filter feeders and to find nearby food sources of their own.