Giant tunnels known as "paleoburrows" in South America, some exceeding a meter in diameter and tens of meters long, were likely dug by giant extinct ground sloths (specifically, scelidotheriines and mylodontines). Researchers used a variety of evidence, including claw marks, sediment analysis, and the burrows' size and shape, to rule out other potential excavators such as armadillos or humans. These immense burrows, which represent the largest ichnofossils (trace fossils) on the continent, provide insight into the behavior and ecology of these megafauna and demonstrate a unique adaptation not seen in extant sloths.
Researchers at the University of Liverpool have identified preserved collagen within a rib bone of a Lufengosaurus, a dinosaur from the Early Jurassic period. This discovery challenges the widely held belief that such soft tissue degrades completely over millions of years. The identified collagen, while fragmented, exhibits similarities to bird and crocodilian collagen, offering potential insights into dinosaur physiology and evolutionary relationships. Further analysis of this exceptionally preserved organic material may revolutionize our understanding of dinosaur biology.
HN commenters are skeptical of the "discovery," pointing out that collagen has been found in dinosaur fossils before, citing multiple examples dating back to 2007 and earlier. They question the novelty of this particular find and suggest the news is likely a misrepresentation or exaggeration of the research, possibly for publicity. Some express frustration with the cyclical nature of such announcements, while others discuss the challenges of definitively identifying ancient proteins and the potential for contamination. A few commenters offer more optimistic perspectives, acknowledging the potential value of further research on preserved collagen, particularly for understanding dinosaur physiology and evolution.
After an absence of roughly 5,000 years, a spotted hyena has been confirmed in Egypt. Researchers identified the animal through camera trap footage captured in Wadi El Gemal National Park, a protected area in the country's Eastern Desert. This rediscovery is significant, as it marks the return of a large carnivore that was once part of Egypt's ancient fauna and suggests potential range expansion for the species. While the hyena's origin—whether it migrated naturally or was accidentally introduced—remains unclear, its presence has sparked both excitement and concern among researchers who are now working to understand the implications for the local ecosystem.
HN commenters discuss the implications of a spotted hyena being found in Egypt after a 5,000-year absence. Some express skepticism about the claim, pointing to historical accounts and anecdotal evidence suggesting hyenas may have been present more recently, albeit rarely. Others highlight the challenges of definitively proving local extinction and subsequent re-emergence versus continuous, low-density presence. The difficulty of species identification from skeletal remains, especially differentiating striped and spotted hyenas, is also raised. Finally, commenters discuss potential reasons for the hyena's scarcity, including habitat loss and human persecution.
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https://news.ycombinator.com/item?id=43082287
HN commenters discuss the likelihood of the giant paleoburrows being created by giant ground sloths, expressing skepticism due to the sheer size and complexity of some tunnels. Several suggest the possibility of multiple generations of sloths expanding the burrows over time, while others question the practicality of such large burrows for creatures needing to escape predators. The lack of claw marks in some sections is noted, prompting speculation about other unknown extinct creatures or even geological processes. Some commenters focus on the implications for understanding megafauna and past ecosystems, highlighting the surprising scale of these ancient burrows and the need for further investigation. One commenter humorously links the lack of clear answers to the enduring mysteries of Göbekli Tepe.
The Hacker News post titled "Who carved South America's mysterious ancient tunnels? [pdf]" has generated several comments discussing the linked study about paleoburrows in South America. The discussion primarily revolves around the creatures responsible for these extensive tunnel systems and the evidence presented in the research.
Several commenters express fascination with the size and extent of the burrows, pointing out the sheer scale of the digging involved. Some question whether extinct giant ground sloths could be the sole creators, considering the enormous amount of earth that had to be moved. The possibility of multiple generations of sloths contributing to the tunnel systems over long periods is raised as a potential explanation.
There's debate regarding the proposed function of these tunnels. While the researchers suggest protection from predators and climate extremes, some commenters speculate about other possibilities, such as social behavior, food storage, or even territorial marking. The idea of interconnected burrow networks forming extensive underground "cities" is a recurring theme, sparking imaginative discussions.
Some commenters focus on the geological aspects, questioning the methodology used to date the burrows and the processes that led to their preservation. The composition of the surrounding sediment and its impact on the burrow's structural integrity over millennia are also discussed.
A few users share personal anecdotes about encountering similar, albeit smaller, animal burrows, offering real-world context to the scale and complexity of the paleoburrows described in the study.
Some skepticism about the definitive attribution to sloths is expressed. Commenters point out the lack of direct fossil evidence within the burrows themselves and propose alternative or contributing excavators, like giant armadillos. The possibility of the burrows serving as habitats for multiple species over time is also considered.
Overall, the comments demonstrate a high level of engagement with the topic, showcasing a mix of scientific curiosity, skepticism, and imaginative speculation regarding the origins and purpose of these ancient tunnels. The discussion reflects the inherent mystery surrounding these paleoburrows and the challenges in reconstructing the behaviors of extinct megafauna.