The Cave Where Turtles Die

by B. N. Sullivan

Back in the early 1980s, the famous ocean explorer Captain Jacques Yves Cousteau and his team made their first visit to Sipadan Island, off the coast of Borneo. They made a film about Sipadan, and one of the highlights in that film was an eerie cave in which they found many bones and skeletons of sea turtles. They had never before seen such a sight, and they were puzzled by it. At the time, they theorized that perhaps old sea turtles just went there to die.

About a decade after Cousteau's first visit to Sipadan, we went there to dive. We had heard about the legendary turtle cave, and it was one of the things at Sipadan that we wanted to see for ourselves. Since it's a potentially dangerous dive, the Sipadan Turtle Cave is restricted to experienced divers who have had appropriate training, and it is essential to go with a guide who knows the terrain inside the cave. Fortunately, we were able to make arrangements to dive the Sipadan Turtle Cave with a veteran guide who knew the cave well.

As underwater caves go, this one is not particularly deep. The entrance to the cave is in the side of a limestone wall that begins a few meters below the surface and plunges straight down to a depth of about 600 meters (about 2,000 ft.). The mouth of the cave, found at a depth of only 20 meters or so (about 65 ft.), is small and partly disguised by large soft corals.

Just inside the cave's narrow mouth is a fairly roomy chamber, where we paused to let our eyes begin to adjust to the darkness. Once we passed beyond this first chamber there was no ambient light at all, so of course the three of us -- the guide, Jerry, and I -- carried multiple lights with us on this dive.

What makes the dive tricky is the cave's interior terrain - an intricate maze of chambers connected by narrow tunnels. The tunnels are not straight: they curve this way and that -- not just left and right, but also up and down, as if the whole works had been built as a bed for a roller coaster.

The bottom of the entire cave system was covered in fine, silty sand, so we had to be extremely careful to stir it up as little as possible as we went along. Once fine sand gets stirred in small spaces like that, visibility is quickly reduced to zero.

We saw and photographed the famous turtle skeletons, which we came across in several of the cave's chambers. Some were no more than disorderly piles of bones, like the first photo on this page. Others were more complete skeletons, with half-disintegrated carapaces, and goofy looking turtle skulls, like the second photo. [Click on any of the photos to enlarge.]

While Cousteau and his group conjectured that old or sick turtles may have gone there intentionally to die, our guide told us that Cousteau's original notion had been replaced more recently by a more prosaic explanation: Turtles occasionally wander into the cave system, perhaps to rest, or to hide from a predator, or maybe just out of curiosity. Then they become lost in the dark, disorienting interior of the cave. When they need to surface for a breath of air, they can't find their way out, so they drown. This explanation, while not as romantic as Cousteau's, made sense to us.

Turtles are not the only air breathing animals to have drowned in that cave. In one of the cave's chambers our guide used his light to direct our attention to a rocky ledge. There was the complete skeleton of an unlucky dolphin, which had shared the fate of the hapless turtles.

Diving in the Sipadan Turtle Cave was one of the highlights of our time at that remarkable little island in the Celebes Sea. We recently unearthed a cache of photos from our first trip there -- not just underwater photos, but some taken on the journey there, and on the island. For the next several posts, we will share some of those photos, and the tales that go with them. Stay tuned.