close
close
Salt Lake – ABC Education

Salt Lake – ABC Education

Salt Lake – ABC Education

Dr Aaron Camens, Flinders University: So what we have here is a skeleton of Diprotodon optatum, the thing that made Callabonna famous. At this end, we have the fragmented remains of the skull. This is so well preserved that we can still see the body as it was when the animal died. We have the spine in the middle, the pelvis in the back, and the legs are still in the position where this giant marsupial fell on its side. This is the largest marsupial that ever lived. It stood about two meters tall at the shoulder, three and a half meters long, weighed over two tons. So it’s about the size of your urban SUV.

Hugh Jackman, Narrator: Five lumbering giants gathered by the water’s edge. There is a new family member. At nine months, this joey is exploring his surroundings, spending less time in his mother’s protective pouch. Diprotodons were widespread throughout much of Ice Age Australia. Males were much larger than females, suggesting that they may have lived in small family groups characterized by a dominant male. Their large nasal cavities may have been used to make deep grunting calls. Like today’s koala, low frequencies would have allowed them to maintain social communication over long distances.

Dr. Aaron Camens: This is one of the most interesting parts of Callabonna for me.

Narrator: The lake bed has preserved the most precious details.

Dr. Aaron Camens: Nowhere else in Australia do we see the soft tissues of megafaunal animals preserved. If we look very closely here, we can see this kind of dimpled surface. Now, this actually records Diprotodon’s foot pads. So where Diprotodon got stuck in the mud here, the mud wrapped around the leg and that impression of the soft skin of the leg was preserved for over 50,000 years.

Narrator: Amazingly, the remains of nearly 900 Diprotodons have been found at Lake Callabonna. So why did they take so many steps here?

Dr. Aaron Camens: If we go back 50,000 years, Lake Callabonna is progressively drying up. We are talking about a period of extreme climate variability, and this climate change could be one of the determining factors of what led to the megafaunal extinction.

Narrator: As the lake contracted over time, the animals were forced to wade through mud to reach the shrinking water source. And the heavier the animal, the more likely it was to get stuck in a muddy grave. Fortunately for this family of giants, they safely navigated the dangers of the lake. But there may have been another deadly consequence to being so large in a drying environment.

Dr. Aaron Camens: So one theory is that because these animals were so large, they may have been very slow to reproduce. They may have had only one joey, as opposed to 2, 3, 4, or even 10, as some of our carnivorous marsupials have. It may have taken many good years in a row, so maybe four or five years of good vegetation to be able to raise the chicks to maturity.

Narrator: As temperatures become more extreme and rainfall changes, what was once a fertile landscape dries up completely. The lake and its vital water have disappeared. Despite his mother’s best efforts, this baby Diprotodon cannot continue.