Aussie's in New Zealand: Swirling water, sandstone caves and glowing worms

Today is our last day in Te Anau prior to heading to the south-east of New Zealand in the morning. We'll be leaving New Zealand's second-largest lake and Fiordland behind, however will take along some good memories of it through a couple of great adventures into the Fiordland National Park that starts right at the edge of town.

You can see my post about yesterdays adventure here and today we headed back into Fiordland to tour the glow worm grotto.

We boarded the boat right out the front of our accommodation that is actually right on the lake and headed to the western side of Lake Te Anau to begin our tour. The caves are off limits without a guide but with one a person is able to get up close and personal with the caves and very close to the glow worms themselves.

The caves
Formed 12,000 years ago the cave-system is considered relatively young. The Tunnel Burn stream that rushes through it originally ran on the surface many metres above, the source being the alpine Lake Orbell high up on the mountain which flows on down into Lake Te Anau below. Over time the water began to cut into the mountain and down into the limestone rock below. The flow has created the caves over many years and indeed still carves out the soft limestone little-by-little changing the caves yearly.

It's interesting to note that Te Anau is said to be a shortened version of words from the Maori language meaning “the cave of the swirling water current” [Te Ana-au]. It is debatable whether the lake and town is named for it, but it cannot be disputed that the caves we visited today certainly have plenty of swirling water!

The caves are 6.7km long however tourists only go 250m inside. There is four levels of caves and, of course, inside is very dark and incredibly dangerous through rapid-flowing swirling waters, slip hazards and cave-ins.

It is said that the caves existed only in legends of the Maori people however keen to locate them Lawson Burrows set out on a quest in 1945. Three years later, in 1948, he found evidence of water disappearing from the surface on the mountain only to reappear at Lake Te Anau. He dove under the lake, swam up a hidden outlet, and emerged inside the caves. [That's a bloke with balls-of-steel.] Soon after, he began a commercial operation taking tourists into the caves - It survives to this day.

The cave system is vast with the highest point being the Cathedral, a cavern twenty metres in height! It is also incredibly important from an ecological perspective and so only a set-number of tourists are permitted each year. This ensures the delicate ecosystem inside the caves is preserved and the plant and animal life outside of it can be managed also.

The tour
Once we arrived at the cave location we assembled into the small group of twelve plus the guide to head down into the caves. The entrance is very low and we had to bend over in half just to enter. We headed down, below a massive rock, along a gangway and into the cave system itself.

Just outside the cave entrance. You can see the very low rock directly in front of the people in the image - That's where a person needs to bend over double to get through, walking that way for a about 4 metres of walkway.

I have to apologise for my photos. They are not great. The thing is that photography is forbidden within the caves. It's just too dangerous to have people playing around with phones rather than watching their footing. At some points it is almost pitch black. When in the glow worm grotto itself it is simply not possible to take photos.

Inside it's very loud as water rushes by at a furious rate. It is crystal clear water and also very cold. The walkway is lit in places and we filed through heading up stairs, deeper and deeper.

Here's one of the waterfalls taken from same level as the falls on the left and from above in the right image. The noise here was deafening and one could not hear another speak even at a shout. To the right side of the right image is the spot I took the left image from - You can just see the platform.

Here's another shot of the same waterfall from a different angle, from above. Remember, I was trying to do this surreptitiously so I didn't get in trouble, so didn't have a lot of time to get it right.

We made our way to a platform 250m into the caves, this one quite poorly lit. We crammed onto it and from the back of the group I could see a punt boat waiting for us, just large enough for the 13 of us.

We boarded and the guide turned his flashlight off. Just before he did I could saw a chain running at standing-head-height which I assume is what he would pull us along with into the grotto ahead. Into the dark we went. When I say dark and mean dark. There was nothing but blackness.

Behind us the booming sound of the water faded away and as far as I could tell we were on a very calm section of water above the main flow, the only sense we were moving was through the sound of the occasional bump of the punt on the walls of the grotto - All sense of movement and distance was lost. It was eerie also as were told to be silent and, as we were further away from the falls, it was incredibly quiet. A whisper could have be heard by all, if someone dared utter one...And then...

...We were outside again. It was night time and we floated under an amazing canopy of a million stars, all aqua or turquoise in colour.

Actually we were still in the grotto and the stars were glow worms; Each a tiny pinprick of aqua/turquoise light. They were in groups, and scattered in a haphazard manner, much like the stars in the sky. I could see what looked like constellations although instead of many different sized ones they were only really two sizes, some larger than the others. It was amazing.

In silence we floated past these glow-worm-constellations marvelling at nature's ingenuity. I felt the boat turning and, navigating by glow worms instead of the stars, I realised we had turned and were heading back to the gantry/boat landing. As we headed away I could see the glow of the worms reflected in the calm black water below giving me the sensation of losing all sense of up and down. It was a very cool experience.

The worms
The life-cycle of a glowworm.

• Egg: 20-24 days - Laid by the female who lays about 130 eggs a year with December-hatching being the most prevalent.
• Larva: 9 months - The larva builds a nest and begins to feed. The glow is designed to attract prey in the otherwise dark caves. It will grow to about 30-40mm then cover itself in a skin suspended from a long thread to become a pupa.
• Pupa: 12-13 days - It takes a couple of weeks for the fly to hatch and in this time the females begin to glow more brightly to attract mates when it's time to hatch and mate.
• Fly: 1-5 days - The female dies rapidly after laying her eggs and the male fly can live up to 5 days.

Glow worms will base themselves in their own nests, individually. They are not unlike a hammock made from silk tread and suspended from the roof of the cave by the threads.

From here they create silk fishing nets which are very tiny threads with a sticky substance on them. It takes about 45 minutes to make one and each glow worm uses many as you can see below. If they catch something they haul in the thread by eating it and secure their prey. They can then regurgitate the thread for use again. Good one nature!

How do they glow
It's a simple chemical reaction of the enzyme luciferase acting on the luciferin substrate - Throw in some adenosine triphosphate and some oxygen and boom, you're glowing. Easy for glow worms, not so easy for you or I though. As stated earlier, the glow to attract prey and mates in the very dark environment.

Image showing the nets that catch prey. This is not my image src

On exiting the caves we saw some videos of this feeding-process happening where the thread had caught a moth. Obviously too big to swallow the worm went in through the softest part, the eye, injecting a mucus to soften up the moth inside. It then dines on moth-smoothie for the next week or so. Fascinating huh?

This is NOT the caves at Te Anau however I've used it to demonstrate what we saw today. This is an image form Waitomo Glowworm Caves, also in New Zealand. src

Here's a shot back at the entrance as someone exits ahead of me. Gratuitous ass-shot of the female backpacker? Yeah, why not. On the right is Faith at the entrance exiting.

From here we headed to the visitor centre for a talk about the worms, caves and other interesting facts about the area including the other animals that call the caves home like the Cave Weta, Long-finned eel and Harvestman which I'll do a post about later considering this one is getting up to 1800 words already. It's interesting to note that these glow worms only occur on New Zealand. There are many others prevalent in Australia such as the ones in a disused rail tunnel in Lithgow which I have also been to, but the ones in Te Anau are unique to New Zealand, just like 75% of the New Zealand Fauna also is.

As the boat sped back towards the Te Anau wharf we chatted about the glow worms adventure and yesterday's Fiordland/Milford Sound shenanigans and decided we'd rate both days as a solid 9.5 out of 10! Te Anau is certainly a winner and we are glad we came here. if you can, get thee here, you'll have a blast!

We're rolling to the south-east tomorrow morning, bound for Dunedin and more adventure-shenanigans and are looking forward to it greatly. Dunedin is our last stop for 4-5 days before we head back up to Queenstown and fly home to Australia. It's too early to think about home just yet though, although we miss the cats very much - Both of whom are showering our cat-house-sitter-champion-friend with plenty of head-butts and cuddles. My friend will have to bugger off when we return...Unless she wants to pay board and lodgings!

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