Caves and Glowworms in New Zealand

New Zealand's range of natural underground formations and caves have fascinating glowworm displays and are perfect for caving and canyoning.

Tourism Activities: Caving | Canyoning | Glowworm Caves | Glowworms

Cave Formation

Most New Zealand caves are formed from limestone and marble sediment. Enormous amounts of calcium rich mollusc shells and skeletons of marine life form a thick strata, which over millions of years, compresses and solidifies. Over time, this sediment cements together to become rock beds.

As rainwater leaches through the soil, a mild solution of carbonic acid is released through cracks in the limestone, enlarging them. The drips also create other cave formations like stalactites. Over time, some passages erode to a large enough extent to become underground streams or rivers.

As a result, a hidden world is created, a world of caves, sinkholes and complex shafts. Waitomo's large limestone deposits have resulted in extensive honeycomb cave networks.

Tourism Activities: Caving | Canyoning | Glowworm Caves | Glowworms

Glowworms

New Zealand caves, riverbanks and other shady crevices provide a home for New Zealand's most famous fly—the glowworm.

The life cycle of a glowworm is about a year from larva to fly. During that period it casts the luminous glow for which it was named. The light is often an eerie blue and is stronger when the worm is hungry. From the ceiling of a cave, the worm suspends lines of sticky beads to trap prey, which are attracted to the light.

Once prey is caught, the glowworm pulls in the line to feed. Looking at a ceiling of glowworms is like gazing at the stars on a clear night.

A mature adult glowworm fly has to be careful not to get trapped in a glowworm line itself, and be eaten!

Tourism Activities: Caving | Canyoning | Glowworm Caves | Glowworms