Research has revealed that prehistoric kangaroos in southern Australia had a wider variety of diets than previously thought. This discovery raises new questions about how they managed to survive and adapt to climate changes, as well as their role in the extinction of the megafauna.
This study, a joint effort between palaeontologists from Flinders University and the Museum and Art Gallery of the Northern Territory (MAGNT), utilized advanced dental analysis techniques to explore tiny wear patterns on the teeth of fossilized kangaroos.
Published in Science, the results indicate that many kangaroo species were generalists, adapting to varied diets in response to environmental shifts.
Focusing on fossilized kangaroo species from the Victoria Fossil Cave in the Naracoorte Caves World Heritage Area in South Australia, this research challenges the longstanding belief that those species that went extinct over 40,000 years ago did so because of narrowly specialized diets.
The Naracoorte Caves World Heritage Area is noted for having the richest and most diverse collection of Pleistocene (2.6 million to 12,000 years ago) kangaroo fossils.
According to lead researcher Dr. Sam Arman from MAGNT and Flinders University, “Our study demonstrates that most prehistoric kangaroos in Naracoorte had a varied diet. This adaptability likely contributed significantly to their survival during historical climate changes.”
Utilizing Dental Microwear Texture Analysis, the team compared diet patterns of 12 extinct kangaroo species with those of 17 contemporary species. The findings contradict earlier beliefs that specific species perished due to highly specialized diets. Instead, it was found that the majority were mixed feeders, capable of consuming both shrubs and grasses.
Co-author Professor Gavin Prideaux from Flinders University noted, “The unique anatomy of the short-faced kangaroo has led to a common perception that sthenurines couldn’t adjust their diets during climate shifts, which ultimately resulted in their extinction.”
“Understanding the ecological functions of Australia’s marsupial megafauna can provide better insights into the evolution of modern ecosystems. This knowledge may also help explain why Australia is particularly susceptible to introduced large mammals like pigs, camels, deer, and horses.”
Dr. Arman added, “Most species of kangaroos from Naracoorte actually shared similar everyday diets, indicative of the most nutritious and readily available food sources.”
He drew an analogy to his 4×4 vehicle, stating, “While I generally don’t require four-wheel drive, having the capability proves essential in challenging conditions when my usual fuel sources are scarce.”
“The Victoria Fossil Cave was an optimal location for our studies, providing the largest sample size to evaluate Pleistocene diets across numerous species. We aim to expand this research to other Pleistocene sites throughout Australia, particularly those covering the 60,000 to 40,000-year interval when numerous megafauna species faced extinction,” he expressed.
While dietary factors may have influenced extinction, understanding the interplay between characteristics like body size and locomotion, as well as their relationships with Pleistocene environments and the human presence, will be crucial.
Grant Gully, manager and curator at the Flinders Palaeontology Lab, stated that this innovative research, which leveraged “advanced analysis and modeling on a significant dataset of 2,650 kangaroo tooth scans,” represents “a significant advancement in understanding the ecology of Australian megafaunal species.”
He continued, “This research enabled us to discern the variations in diets among individuals and locations for modern species, and use that data as a foundation to explore fossil species’ diets over time.”
The authors express gratitude to the Meintangk, Marditjali, and Potaruwutj peoples, the traditional custodians of the Naracoorte area, and give thanks to the volunteers, students, and scientists who contributed to the gathering and preparation of specimens from the Victoria Fossil Cave. This initiative reflects a longstanding partnership between Flinders University and MAGNT, integrating cutting-edge techniques with paleontological expertise to deepen our comprehension of Australia’s exceptional prehistoric ecosystems.
