How do animals live in pitch-dark caves?

How it works

Deep caves are dark and damp, stay at much the same temperature all year and have very little food. Animals that spend their whole lives there often have tiny eyes or none at all, and pale bodies. In darkness, eyes and colour are not much use, so energy goes elsewhere.

Instead of sight, they use other senses. Some have antennae and legs far longer than their bodies, sweeping them around like a walking stick. Others can sense smells or tiny ripples in water. Many use energy very slowly, so they can survive a long time without food.

A few animals make their own light. New Zealand's glow-worms, the larvae (young stage) of a small fly called a fungus gnat, give off a blue-green glow that lures insects into sticky threads. Other animals only use the cave entrance, sheltering inside by day and leaving at night to feed.

Where to see it in New Zealand

At Waitomo Caves and the Te Anau Glowworm Caves in Fiordland, cave ceilings shine with glow-worms like a starry sky. Many New Zealand caves and shady rock crevices are also home to cave wētā, long-legged insects that feel their way through the dark with very long antennae.

Try it together

In a cleared space at home, wear a blindfold while a family member places a few safe objects on a table. Use only your fingertips and nose to work out what each one is. That is how many cave animals explore. Stay well away from stairs.