The main reason I wanted to venture into the caves was to see the glow worms.  Glow worms are found only in New Zealand and are easiest to find and see in caves.  Though they sound magical and beautiful like fireflies, the glow worm is actually just the larvae stage of a flying insect.  From far away the glow worms look awesome but up close they look pretty gross - more like phosphorescent maggots. 



The glow worms of New Zealand produce a chemical reaction in their rear ends that causes a glow because they are trying to attract food.  It all starts with a type of fly that hatches in the water under the rocks of creeks and rivers.  When the fly reaches a certain stage in its life cycle, it emerges from the water and flies upward using the stars in the sky as guidance as to which way is up. 

Glow worm nets and webs

Since there are creeks and rivers that run through the cave systems in New Zealand, the flies live there as well except instead of flying upwards toward the stars, they fly up toward the glow worms (which really look like stars) and get caught in their sticky nets.  The glow worms then eat the flies, grow big and fat and can eventually form their own little cocoon to begin to fly themselves.

Glow worm up close with his rear lit up

It can be very tricky to see glow worms because they only light up their butts when it's dark out.  Caves are a good way to see them as they are dark all the time.  But when a group of cavers appear with bright headlamps, the glow worms promptly shut themselves off.  To see them again, one has to wait patiently in the dark and watch them get brighter and brighter.  This makes it next to impossible to photograph a glow worm.  To take the pictures that you see on this blog, our guide had the shutter of his camera open for 30 seconds and told us to sit very still.  I thought the results were pretty cool!

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