Carbon dating of recent archaeological finds has indicated that Tau was one of the first places humans settled when they arrived in Fiji and the cave would have made a great home for people newly arrived in a strange land.
The steep access track, slippery from recent rain and in places squishy with fallen mangoes, certainly looked easy to defend.
But once inside, the cave is surprisingly spacious, with a lofty vaulted limestone roof above a flat area lit by several openings where, according to Ratu, "the people went about their daily living, meeting each other, preparing food, cooking and eating".
He showed us a deep vomo pit "excavated by archaeologists from the university" strategically placed under one of the openings "so the smoke could go straight out and not suffocate the people". Next to it was a circle of stones which acted as the fireplace.
Further into the cave, separated from the living area by a low stone barrier, was a smaller flat space "where children could play". Further in again was an unlit cavern "which was the sleeping area".
As we walked into the darkness of the sleeping area, a sort of clicking noise, which had been going on in the background, suddenly gained in volume.
When a torch was shone on the roof, we saw a seething mass of bats and birds - swiftlets - circling above. There must have been tens of thousands of them.
"There weren't so many here when the caves were lived in," said Ratu. "They have moved in since the people left."
Ratu walked across to a corner of the cave where a great mound of brown material ran almost to the roof. "Droppings," he said. "From the birds and bats."
When we got back outside the bat alarm was in full swing. The sky above the cave was black with excited bats. "In the village they will know we are here," said Ratu.
"If we were here without the proper permission they would come up and check."
There are three significant caves on this limestone outcrop.
The cave we visited - called Oho or "occupied cave" - was for many generations the dwelling place of the Tau villagers. "Many people lived in the cave, sometimes as many as a hundred," said Ratu, "and others built houses up here on the side of the hill".
Not far away - but closed to outsiders - is the cemetery cave where generations of Tau people have been buried.
And finally, its location kept secret even today, is "the refuge cave", where the villagers would take sanctuary when they were attacked. "Tau has never been defeated. Even when the whole of this province was conquered, they could not defeat Tau."
These days, the village of Tau is down on the flat and, as we walked back down the steep, winding path - once marked only with secret signs cut into the tree bark, but today lined with white stones - Ratu explained that the village had occupied three sites over the centuries.
First there was the cave. Then when Fiji became more peaceful, a traditional village was built at the bottom of the limestone outcrop. And finally, as the village grew in size, it shifted to its present site where there was more flat land for expansion.
At one point, there was a limestone processing plant here and its huge abandoned chimney towered above the access track like an ancient temple.
When we reached the village, preparations for an important funeral were under way. The younger men were building a huge temporary shelter to accommodate the expected influx of visitors and the older women were setting out woven mats on the floor of the chiefly bure, distinguished by its traditional thatched roof and raised above the other houses to signal its occupant's higher status.
A silver-headed patriarch explained, through my Tourism Fiji guide Thomas, that the funeral was for a high-ranking man who had been about to be installed as the village chief when he unexpectedly died. Then he told a youngster to take me to the bure where the women enthusiastically posed for photos and then unrolled the huge tapa cloth made in the dead man's honour.
After that, I was invited into the village's meeting hut to join the older men for a few bowls of kava followed by a feast: delicious fish in a wonderful coconut milk, onion and chilli sauce, coconut cream wrapped in young taro leaves, cassava, chicken and slices of mango.
As I ate, the kava drinkers kept calling out - according to Thomas - "Eat more, eat more", but there was still masses of food left when I stopped.
"Sorry I can't eat it all," I told the smiling woman presiding over the food.
"That's all right," she replied. "The men will finish it off when they stop drinking kava."
CHECKLIST
Getting there: Air Pacific flies from New Zealand to Nadi and Suva.
Where to stay: The small, tranquil Tambua Sands Beach Resort and the big, bustling Sonaisali Island Resort are within easy striking distance of Lomawai and Tau villages.
What to do: Fiji Eco Tours.
Further information: See fijime.com.
Jim Eagles travelled as a guest of Tourism Fiji.
