Three Million Bats

Deer Cave, at Mulu National Park, Borneo, is one of the largest cave chambers in the world, and home to as many as three million bats. Towards twilight, on evenings when it’s not raining, they swarm out to hunt in the forest around, consuming as many as fifteen tonnes of insects every evening.

They follow a crazy, spiralling, swirling route, fizzing up in a stream of smoke, more like hornets, locusts or bees than mammals. The aim? To frustrate the hawks, which hover above the limestone crags which mark the cave entrance, diving into the morass in search of prey.

The bats of Deer Cave, as it happens, are the focus of one the world’s crazier ecosystems. Deer Cave’s grey-green crags, eroded walls, and speleothems, are all, pretty much, submerged in a torrent of rich, brown guano, the largest piles of bat droppings in the world.

On the guano grows a fungus. Which feeds insects. Which, in their turn, will feed the critters trapped first by chance and then by evolution in the caves around here: white crabs, blind fish, wingless crickets, poisonous centipedes with 20cm antennae… The salt in the droppings dissolves in the water, making the stream which flows through the cave a mecca for deer (and the folk who hunted them).
View into green doline outside a cave, with waterfall tumbling past.

Yet, for all the acrid, slightly ammoniacal smell of guano, Deer Cave is a beautiful place. The scale of it knocks you sideways: stadiums, not cathedrals, are the best comparison. Then, as you curve around the sides of the cavernous entrance, and ascend over dark, blurred speleothems, past tiny, dark-furred bats, this appears: the Garden of Eden, with a waterfall shower and calm pool.

Thanks to Debbie at Delicious Baby for hosting Photo Friday.

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8 Responses

  1. Cool! We were just watching a bunch of bats at Pont du Gard in Provence, France. they seemed to come out at 9 pm and gave us a show.

    This looks like a great place to check out when our family world tour takes us to Asia this fall and winter!

    • MummyT says:

      I would totally recommend you take in Borneo. You need to plan ahead to get the good deals, generally speaking, but there are wonderful caves in the whole of Mulu. The trails to the main caves are all plank walks and concrete, so very do-able even if you have mobility challenges. Also just a very lovely place to watch the world go by.

  2. Very cool! Of course, I went running when I found a bat in the basement.

    • MummyT says:

      Yes… The boy thought they were very sweet and human-looking when we met some up close. I find them vaguely disturbing. There’s something unformed and foetal about them when you see them close up. En masse, however, they’re amazing…

  3. I have to admit, I’m not fond of bats or caves (or the batcave smell), but great job capturing the feeling of a large bat movement – it made my skin crawl 😉

    Thanks so much for joining in.

  4. Crystal aka Travelers Barista says:

    Very neat…would love to see a bat cave some time. Actually a cave in general would be neat. I haven’t seen much of anything amazing as far as caves go.
    There are some neat looking ones in New Mexico I’d like to visit.
    Great pics!

    • MummyT says:

      There are several absolutely stunning caves in Mulu National Park — one of the main reasons it’s a World Heritage Site.

  5. Video, yay! I was starting to think that only I used the video function :p I have always wanted to see the bats at Carlsbad in New Mexico, USA, but never have caught them at the right time of year.