Category Archives: Megafaunal extinctions

A “gold mine” within a gold mine

by Tim Rabanus-Wallace and Julien Soubrier

Recently, we had the opportunity to collect frozen bone remains directly from the permafrost in Canada, as part of our research on the evolution of flora and megafauna throughout the climate variations of the late Pleistocene (~10 to 100 thousand years ago). The two of us, along with ACAD director, Alan Cooper, travelled to the gold rush city of Dawson in the Yukon, where a few families are still mining for gold in the frozen soil. To reach the gold-rich layers, miners are using high-pressure water to accelerate the natural thawing of the permafrost, uncovering numerous fossil bones (our gold mine!) in the process. Most of these bones are from large mammals who were grazing in the steppes of the Berigian region a few millennia ago: mammoths, horses, and bison; though the burrows of ancient squirrels also survive, with fascinating plant material inside. Continue reading

The lost Mediterranean cave-goat: A tale told by ancient DNA

By Pere Bover

The islands of Mallorca and Menorca (Balearic Islands) in the Mediterranean Sea. The red line indicates the coast line during a maximum glacial event.

The islands of Mallorca and Menorca (Balearic Islands) in the Mediterranean Sea. The red line indicates the coast line during a maximum glacial event. Credit P. Bover

You may be wondering what a goat was doing in a cave. So was I, which is the reason I started caving around 20 years ago. In fact, these animals aren’t strictly goats, but they looked very similar (they were bovids, more closely related to sheep than goats). Sadly they are now all extinct. They intrigued me so much that the main topic of my PhD thesis was based on one of these species, Myotragus balearicus. M. balearicus is from the Balearic Islands in the Western Mediterranean. These islands, including Mallorca, with a surface of 3,640 km2 (yep! around 25 times smaller than Tasmania!!) and Menorca with 702 km2, have been isolated from the mainland since the Mediterranean basin flooding in the Late Miocene (around 5.35 Million years ago). M. balearicus survived on these two tiny islands until the first human arrival around 4,500 years ago.

For a mysterious reason these bovids liked inhabiting caves, and not just the areas surrounding the entrance, but also in deep galleries. Skeletal remains of Myotragus found in these deep galleries suggest that the animal was using caves as shelter Continue reading

Descending into Natural Trap Cave – A Scientist’s Day in the Office

By Alan Cooper and Laura Weyrich

Caving (rappelling), fossil finds, bone grinding, DNA sampling and fieldwork all in a day’s work.  Here Alan Cooper descends into the Natural Trap Cave, Wyoming to collect unique animal fossils for sampling, to be subsequently analysed at ACAD.

What happens at Camp, stays at Camp… or does it?

by Tim Rabanus-Wallace

Tim presents a snapshot of life on the Dawson Field Camp during the July 2014 Yukon field expedition, introduces you to the crew, and talks about some of the considerations that go into ancient DNA fieldwork.

Digging up frozen bones in gold mines

by Julien Soubrier

As part of our research on the evolution of flora and megafauna throughout the climate variations of the late Pleistocene (~10 to 100 thousand years ago), we had the opportunity to collect frozen bone remains directly from the permafrost in Canada. Three of us traveled to the gold rush city of Dawson in the Yukon, where a few families are still mining for gold in the frozen soil. To reach the gold-rich layers, miners are using high-pressure water to accelerate the natural thawing of the permafrost, uncovering numerous bone remains in the process. Most of these bones are from large mammals who were grazing in the steppes of the Berigian region a few millennia ago: mammoths, horses, bison…

Placer mining. Recycled water is pumped into the mine face at high pressure, melting the ice and revealing the gold-bearing gravels. After a claim is worked in the way, miners reform the land using excavators, allowing local plants to recolonise, and the environment to rapidly recover.   Yukon_C_2014Sml

Above: Placer mining. Recycled water is pumped into the mine face at high pressure, melting the ice and revealing the gold-bearing gravels. After a claim is worked in the way, miners reform the land using excavators, allowing local plants to recolonise, and the environment to rapidly recover.

Continue reading

Natural Trap Cave: First instalment of year 1 of the field project.

by Alan Cooper

Having rigged the cave on the first day, I guess it was appropriate that I was the one to take the first descent into the chasm below. It’s caving lore something along the lines of the Captain going down with his ship – if you rigged it, you should be first to ‘test’ it out! Backing over the ledge and unlocking my brakebar, I descended about 3 m against a series of ledges – before dropping into open space. Looking around I could see several enormous nests, around a metre wide and made of big branches – eagles had obviously lived under the overhang of the cave entrance for many years, presumably until the grid was placed over the entrance. I’ve not seen eagle nests up close before and it was impressed how large they were. Pack rats were also nesting around these ledges – 100ft over space, and we saw several snake skeletons down in the cave attesting to the effective security systems surrounding their home! Continue reading

How do you get 10 scientists (safely) down a 100 ft vertical shaft?

By Alan Cooper

Natural Trap Cave (NTC) has an impressive entrance pitch – which is concealed immediately below a large innocuous looking slab of limestone, in the middle of a gently sloping ridge overlooking Bighorn Lake on the border between Wyoming and Montana. As you walk across the slab you can see why anything with hooves, or running at speed, would have had no time to react when the cave entrance came into view – suddenly all the edges slope inwards steeply, and you’re looking straight down a hole, about 30ft wide, 100ft onto rocks at the bottom of a large chamber. As a result, over the last 100,000 years or so, a very large accumulation of skeletons has built up in the sediments below – standard herbivores such as bison, horse, and mountain sheep but also large numbers of carnivores including American Lion and cheetah-like cat (really a puma on steroids), many wolves, and even giant short-faced bears  and mammoths. Continue reading

Insights from Natural Trap Cave

Alan Cooper answers your questions while in the stunning Natural Trap Cave, Wyoming. Find out how the team uncover, protect, and transport samples to our ancient DNA lab. Also, how this archaeological dig is part of Alan Cooper’s favourite ongoing project.

The source of the genetics: searching for the remains of the world’s large land mammals.

By Laura S. Weyrich

Our ancient animal, human, plant, and even bacterial samples are obtained from around the world and, though we conduct much of our work in ACAD’s ancient DNA laboratories, we do get the chance to visit some of the amazing places where ancient DNA may be lurking. One of Alan Cooper’s key interests is the extinction of the world’s megafauna (i.e. the super large mammals that roamed the planet thousands of years ago). Recently, Alan and several of his American collaborators were successful in a National Science Foundation grant to excavate Natural Trap Cave, in Wyoming, USA, to obtain megafaunal bones of extinct animals Continue reading

Emu no longer the closest relative to the kiwi – but, what is?

Research published this month reveals the closest relative to the kiwi is, in fact, the extinct Madagascan elephant bird, not the emu, as was previously thought. For over ten decades, researchers have thought the kiwi found its way to New Zealand via continental drift, 130 million years ago. However, due to recent ancient DNA advances, this new study explains that the flightless kiwi originally found its way to New Zealand through flight!

Here, Professor Alan Cooper talks to Radio New Zealand National’s reporter, Kim Hill, and explains how this research came together – a story spanning 20 years.  Continue reading