Where in the World?: Waitomo Glowworm Caves

Step inside most caves and you’ll be enveloped in darkness. But no flashlight is needed in the Waitomo Glowworm Caves on New Zealand’s North Island. The caves’ walls twinkle with light from tiny bioluminescent creatures called glowworms!

The glowworms are larvae, or immature forms, of insects called fungus gnats. They live on the cave walls and glow to attract the insects they eat.

Much of the rock that makes up New Zealand’s crust, or outer layer of Earth, is limestone. This rock was once on the ocean floor. Millions of years ago, as Earth’s crust shifted, the rock was lifted above the ocean’s surface. Over time, rainwater dissolved holes in the exposed rock, forming underground caves. Today, rivers flow through the cave systems.

Glowworms live in New Zealand’s many caves. But the caves in Waitomo are considered the most spectacular. Thousands of tourists visit each year!

There are about 180 miles of known cave systems in Waitomo, with ceilings from 20 to 165 feet high. 

An organ near the glowworm’s tail glows to attract insect prey. The insects get trapped in sticky mucus strands that the glowworm produces. 

Limestone is made of shells and skeletons of tiny ocean animals that have been pressed together over millions of years.