Latest news with #Hocknull
The Star
06-05-2025
- Science
- The Star
How giant prehistoric kangaroos died
Hocknull holding a Protemnodon skull fossil. Photo: Handout/ University of Wollongong/AFP Giant prehistoric kangaroos perished when "climate upheaval" turned lush Australian rainforest into desert, scientists said on April 24 after studying ancient fossils with new techniques. Weighing as much as 170kg – almost twice as hefty as the chunkiest living kangaroos – the extinct "Protemnodon" bounded across Australia as many as five million years ago. Researchers were able to recreate the foraging habits of one population by matching long-lived chemicals from fossilised teeth to recently unearthed rocks. Similarities in chemical composition helped to mark how far the kangaroos hopped in search of food. "Imagine ancient GPS trackers," said Queensland Museum scientist Scott Hocknull. "We can use the fossils to track individuals, where they moved, what they ate, who they lived with and how they died – it's like Palaeo Big Brother." Scientists found the mega-herbivores lived in what was then a verdant rainforest – barely venturing far from home to forage. Lead researcher and UOW PhD candidate Chris Laurikainen Gaete with a tooth fossil from a giant kangaroo. Photo AFP The rainforest started to wither around 300,000 years ago as the region's climate turned "increasingly dry and unstable". "The giant kangaroos' desire to stay close to home, during a time of major climate upheaval 300,000 years ago, likely contributed to their demise," the researchers said. Species of giant kangaroo survived in other parts of Australia and Papua New Guinea, with the last populations surviving until around 40,000 years ago. Scientist Anthony Dosseto said the new techniques could be used to better understand the disappearance of Australia's megafauna. Prehistoric species of giant echidna, wombat-like marsupials weighing over two tonnes, and hulking flesh-eating lizards once roamed the Australian continent. "The debate about the extinction of the Australian megafauna has been going on for decades, but now we can take it to an individual and species-by-species perspective," said Dosseto, from the Wollongong Isotope Geochronology Lab. "With these precise techniques, each site and each individual can now be used to test and build more accurate extinction scenarios." The findings were published in peer-reviewed journal PLOS One. – AFP
7NEWS
26-04-2025
- Science
- 7NEWS
Massive ancient kangaroos became extinct because they were ‘homebodies', scientists believe
Massive kangaroos which roamed Australia more than 40,000 years ago likely became extinct because they were 'homebodies' and did not travel far, even in the face of climate changes. New research shows the kangaroos known as protemnodon — which weighed up to 170kg, twice as heavy as a modern-day male red kangaroo — mostly kept to the same rainforest areas in northern Queensland. This led to their extinction when a lack of rain caused the rainforests around what is now the Mount Etna Caves National Park to disappear, the research published in the science journal PLOS One reveals. The behaviour contrasts with today's kangaroos which often roam vast distances in search of new food and water sources during changes in climate, such as drought. Protemnodon were 'real homebodies', according to vertebrate palaeontologist and Queensland Museum senior curator Dr Scott Hocknull, who co-authored the study with other experts including University of Wollongong palaeo-ecologist Chris Laurikainen Gaete. 'These gigantic kangaroos were just chilling at home, eating the rainforest leaves because there were heaps of them around,' Hocknull said. 'The environment was quite stable. It meant that over hundreds of thousands of years, these animals decided that staying put was a good bet.' The limestone caves around the Mount Etna region, north of Rockhampton, also likely provided protection from ancient predators such as marsupial lions. However, the findings came as a surprise to researchers who predicted the mighty prehistoric roos might have a vast territory due to their size. 'We were astounded to find that they didn't move far at all,' Laurikainen Gaete said. Previous research suggests it was the protemnodon's body shape and size which rendered them incapable of long-distance roaming. New technology The latest study used new isotopic technology — which the researchers said has 'blown our field wide open: — along with fossil teeth remains found around Mount Etna Caves to learn about the large marsupial's behaviours. 'Imagine ancient GPS trackers — we can use the fossils to track individuals and know where they moved, what they ate, who they lived with and how they died,' Hocknull said. 't's palaeontology Big Brother. It fundamentally shifts how palaeontologists and ecologists look at the fossil record.' The researchers also applied similar techniques to smaller kangaroo fossils. 'Many of the kangaroos found as fossils at Mount Etna and Capricorn Caves, including tree kangaroos, pademelons, and rock wallabies, have living descendants in the wet tropics and Papua New Guinea,' Laurikainen Gaete said. 'We will now apply these same techniques to understand how these surviving kangaroo species responded to the same environmental changes that drove the megafauna extinct.'
NDTV
25-04-2025
- Science
- NDTV
Fossil Teeth Reveal Secrets Of Extinct Giant Kangaroo's Lifestyle
Wollongong: Large kangaroos today roam long distances across the outback, often surviving droughts by moving in mobs to find new food when pickings are slim. But not all kangaroos have been this way. In new research published today in PLOS One, we found giant kangaroos that once lived in eastern Australia were far less mobile, making them vulnerable to changes in local environmental conditions. We discovered fossilised teeth of the now extinct giant kangaroo genus Protemnodon at Mount Etna Caves, north of Rockhampton, in central eastern Queensland. Analysing the teeth gave us a glimpse into the past movements of these extinct giants, hundreds of thousands of years ago. Our results show Protemnodon did not forage across great distances, instead living in a lush and stable rainforest utopia. However, this utopia began to decline when the climate became drier with more pronounced seasons - spelling doom for Mount Etna's giant roos. Mount Etna Caves The Mount Etna Caves National Park and nearby Capricorn Caves hold remarkable records of life over hundreds of thousands of years. Fossils accumulated in the caves because they acted like giant pitfall traps and also lairs of predators such as thylacines, Tasmanian devils, marsupial lions, owls, raptors and the now-endangered ghost bats. Large parts of the region were once mined for lime and cement. One of us (Hocknull) worked closely with mine managers to safely remove and stockpile fossil deposits from now-destroyed caves for scientific research which still continues. As part of our study we dated fossils using an approach called uranium-series dating, and the sediment around them with a different technique called luminescence dating. Our results suggest the giant kangaroos lived around the caves from at least 500,000 years ago to about 280,000 years ago. After this they disappeared from the Mount Etna fossil record. At the time, Mount Etna hosted a rich rainforest habitat, comparable to modern day New Guinea. As the climate became drier between 280,000 and 205,000 years ago, rainforest-dwelling species including Protemnodon vanished from the area, replaced by those adapted to a dry, arid environment. You are what you eat Our study looked at how far Protemnodon travelled to find food. The general trend in mammals is that bigger creatures range farther. This trend holds for modern kangaroos, so we expected giant extinct kangaroos like Protemnodon would also have had large ranges. Teeth record a chemical signature of the food you eat. By looking at different isotopes of the element strontium in tooth enamel, we can study the foraging ranges of extinct animals. Varying abundances of strontium isotopes reflect the chemical fingerprint of the plants an animal ate, as well as the geology and soils where the plant grew. By matching chemical signatures in the teeth to local signatures in the environment, we could estimate where these ancient animals travelled to obtain food. Eat local, die local Our results showed Protemnodon from Mount Etna didn't travel far beyond the local limestone in which the caves and fossils were found. This is much a smaller range than we predicted range based on their body mass. We think the small foraging range of Protemnodon at Mount Etna was an adaptation to millions of years of stable food supply in the rainforest. They likely had little need to travel to find food. Fossil evidence also suggests some species of Protemnodon walked on all fours rather than hopped. This would have constrained their ability to travel great distances, but is a great strategy for living in rainforests. One question remains to be answered: if they didn't need to move far to find food, why did they grow so big in the first place? A local adaptation or a species trait? The extinction of Australia's megafauna - long-vanished beasts such the "marsupial lion" Thylacoleo and the three-tonne Diprotodon - has long been debated. It has often been assumed that megafauna species responded in the same way to environmental changes wherever they lived. However, we may have underestimated the role of local adaptations. This particularly holds true for Protemnodon, with a recent study suggesting significant variation in diet and movement across different environments. Similar small foraging ranges have been suggested for Protemnodon that lived near Bingara and Wellington Caves, New South Wales. Perhaps it was common for Protemnodon populations in stable habitats across eastern Australia to be homebodies - and this may have proved their Achilles' heel when environmental conditions changed. Extinction, one by one As a rule, creatures with a small home range have a limited ability to move elsewhere. So if the something happens to their local habitat, they may be in big trouble. At Mount Etna, Protemnodon thrived for hundreds of thousands of years in the stable rainforest environment. But as the environment became more arid, and resources increasingly patchy, they may have been unable to traverse the growing gaps between patches of forest or retreat elsewhere. One key result of our study is that Protodemnon was locally extinct at Mt Etna long before humans turned up, which rules out human influence. The techniques used in this study will help us to learn about how Australia's megafauna responded to changing environments in more detail. This approach moves the Australian megafauna extinction debate away from the traditional continental catch-all hypotheses - instead we can look at local populations in specific sites, and understand the unique factors driving local extinction events. Christopher Laurikainen Gaete, PhD Candidate, University of Wollongong; Anthony Dosseto, Professor of Geochemistry, University of Wollongong; Lee Arnold, Associate Professor in Earth Sciences, University of Adelaide, University of Wollongong, and Scott Hocknull, Senior Scientist and Curator, Geosciences, Queensland Museum, and Honorary Research Fellow, The University of Melbourne This article is republished from The Conversation under a Creative Commons license. Read the original article. (Authors: Christopher Laurikainen Gaete PhD Candidate, University of Wollongong Anthony Dosset Professor of Geochemistry, University of Wollongong Lee Arnold Associate Professor in Earth Sciences, University of Adelaide, University of Wollongong Scott Hocknull Senior Scientist and Curator, Geosciences, Queensland Museum, and Honorary Research Fellow, The University of Melbourne) (Disclosure statement: The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.)
The Guardian
23-04-2025
- Science
- The Guardian
Giant prehistoric kangaroos preferred to ‘chill at home' and didn't like to go out much, scientists say
Despite their immense size, species of prehistoric giant kangaroos from a site in Queensland were probably homebodies with a surprisingly small range compared to other kangaroos, according to new Australian research. Protemnodon, which roamed the Australian continent between 5m and 40,000 years ago and is now extinct, was significantly larger than its modern relatives. Some species weighed up to 170kg, making them more than twice as heavy as the largest red kangaroo. Given their size, researchers expected they might have an expansive territory, said University of Wollongong palaeo-ecologist Chris Laurikainen Gaete, the co-author of the study published in PLOS One. That's because in most modern plant-eating mammals, including kangaroos and other macropods, larger body size correlated with geographic range, he said. A small marsupial such as the pademelon, for example, occupies an area smaller than a kilometre squared, whereas the red kangaroo – the largest of all kinds – in outback Australia can hop long distances, sometimes further than 20km. But analysis of fossil teeth found near Mt Etna, 30km north of Rockhampton in Queensland, revealed something quite different. These protemnodon kept to close quarters, living and dying near the caves where their remains were found. Co-author Dr Scott Hocknull, a vertebrate palaeontologist and senior curator at the Queensland Museum, said the individuals from Mt Etna seemed to be 'real homebodies' that stayed within 'a tiny pocket' in and around the limestone caves. 'These gigantic kangaroos were just chilling at home, eating the rainforest leaves, because there were heaps of them around. That also means that the environment was quite stable. It meant that over hundreds of thousands of years, these animals decided that staying put was a good bet.' Sign up for the Afternoon Update: Election 2025 email newsletter The population at Mt Etna was 'probably quite happy' for some time, Hocknull said. The rainforest probably provided a reliable source of food, while the caves offered protection from prehistoric predators, such as marsupial lions. But their restricted range was a 'bad bet' in the end, Hocknull said, because it pre-disposed them to a risk of extinction when a changing climate and increasing aridity disrupted the rainforest environment about 280,000 years ago. Dr Isaac Kerr, who specialises in kangaroo palaeontology at Flinders University and was not involved with the study, said protemnodon fossils – found mainly in the south and east of the country – indicated there were several species adapted to different environments. 'Probably they were all over the whole continent, including New Guinea,' he said. A site in Tasmania had one of the latest surviving species, dated to 41,000 years ago. Sign up to Afternoon Update: Election 2025 Our Australian afternoon update breaks down the key election campaign stories of the day, telling you what's happening and why it matters after newsletter promotion Kerr said these megafauna kangaroos ranged in size but were generally stockier than their modern counterparts, with shorter feet. Protemnodon probably looked something like a wallaroo, he said, 'squat and muscular but still quite large compared to a modern kangaroo'. Mt Etna is one of Australia's richest fossil sites, containing evidence of ancient Pleistocene rainforests and records covering periods of past environmental change when rainforests gave way to open, arid environments. The researchers' next step was to apply similar techniques to fossils of smaller kangaroos such as tree kangaroos, pademelons and rock wallabies from Mt Etna, which still have living descendants, to understand how they survived the environmental changes while protemnodon died out. The study compared the unique chemical signatures found in the local geology with those found in the fossilised teeth to establish the range of each animal, Gaete said. 'Strontium is an element that varies in the environment, specifically in underlying bedrocks – so a limestone will have a significantly different strontium signature compared to something like volcanic rock or basalt,' he said. These unique signatures made their way into soil and plants, and were reflected in the fossilised teeth of herbivores that ate those plants. Laurikainen Gaete said the technique could be used to understand, on a site-by-site basis, why certain species of megafauna disappeared from particular places. Hocknull said: 'It fundamentally shifts how palaeontologists and ecologists look at the fossil record.'
