Leaena’s Breath Cave
This 73m-long underground chamber has functioned like a massive natural pitfall trap for hundreds of thousands of years. Animals fell in, flew in or were brought into the cave by predators and, unable to escape, died there.
MUCH OF OUR KNOWLEDGE of Nullarbor prehistory comes from fossil remains found in underground caves, which are characteristic of a karst landscape due to its porous underlying limestone bedrock. Leaena’s Breath Cave (LBC) is one of three large caves beneath the Nullarbor known collectively as the Thylacoleo Caves. These formed more than 4 million years ago, and ongoing and occasional roof collapses have expanded them into what we see today.
Karst caves can be palaeontological treasure-troves and that’s exactly what we have on the Nullarbor. Their cool, dry environments and protection they offer from the elements or disturbance by animals or humans can result in exceptionally preserved specimens. They can be used as roosts or dens, meaning there may be large bone assemblages representing the leftovers of meals. And, as for some of the Nullarbor caves, they may also become traps.
An underground cave’s presence may only be betrayed by a small hole drilled through the limestone by water. Animals may walk, f ly or fall in, and, through injury, disorientation or an inability to climb, be unable to make
Karst caves can be palaeontological treasure-troves and that’s exactly what we have on the Nullarbor.
their way out again. LBC presents just such a pitfall trap.
Its funnel-shaped entrance was first documented by caver and fossil enthusiast Paul Devine in April 2002 as he headed across the Nullarbor landscape to join a group of cavers. With the sun setting, he quickly tied off a rope to his four-wheel-drive, and abseiled down through the small opening to the cave f loor some 20m below. What Devine found was to rewrite the Pleistocene history (1.8 million–11,700 years ago) of the Nullarbor.
A large silt f loor was littered with bones. Some, along with mummif ied remains, were recent victims of the deadly trap, but others Devine recognised as belonging to creatures long gone from the Nullarbor of today. Ducking under a rock overhang, he crawled up a low passage and was confronted by a near-complete skeleton of the marsupial lion, Thylacoleo carnifex, stretched out where it had died a lonely death from thirst or injury several hundred thousand years earlier. Sadly, Devine, who was a pivotal member of subsequent LBC expeditions, died in 2012. But his legacy is being built upon by a team of researchers led by palaeontologist Gavin Prideaux from Flinders University in Adelaide.
The Nullarbor’s Pleistocene landscape may have resembled open mallee woodland and the small cave entrance would have been hard to spot in the vegetation. 2 1 3 4 5
This photo shows part of the cave floor from a rockfall at the narrowest part of the cave. The tops of stalagmites can be seen poking up out of the sediment that has accumulated around them.
Stunning stalactites are found in the cave. The upper sediment in the cave and its fossils have been dated to at least 400,000–200,000 years old, thanks to an encrustation of stalactite material on a fossilised skull on the cave floor.
Sediment on the cave floor is excavated in 5cm layers, called ‘spits’, in a grid formation. This fine material, which accumulated over thousands of years and contains a wealth of small bones, sits in a layer 1.5m deep atop a rock floor.
A solution pipe drilled naturally through the limestone by water opens into the cave about 20m below. Here, the first person to document the cave’s existence, Paul Devine, abseils through this entrance during a 2002 expedition.