Graphic showing functional optimality drives repeated evolution of extreme saber tooth forms (Credit: Tahlia Pollock)NewsletterSign up for our email newsletter for the latest science newsThe curved teeth of the saber-tooth tiger represents an evolutionary paradox. Gaining its trademark curved fangs made it functionally optimal for piercing the flesh of its prey. But that level of evolutionary specialization may have also contributed to the big cat's demise about 10,000 years ago, according to a new study published in Current Biology. Our study helps us better understand how extreme adaptations evolve not just in saber-toothed predators but across nature, Tahlia Pollock, a Bristol University researcher and author of the paper, said in a press release.Learning How Teeth Shape Affect Hunting AbilityTo reach that conclusion, a team of researchers first used computer simulations on 235 teeth representing 95 different meat-eating mammals including 25 from various saber-toothed ones. Then they 3-D printed 14 stainless steel teeth covering the range of shapes, and measured the amount of force each model tooth needed to puncture gelatin. The team analyzed a wide variety of teeth shapes and sizes. They were especially interested in the balance between curved versus straight and slender versus thick. "There is a trade-off between the aspects of shape that improve food fracture and those that increase tooth strength, according to the paper.Not surprisingly, the classic saber-toothed tiger Smilodon fatalis as well as its lesser well-known cousin, the false saber-toothed Barbourofelis fricki scored the highest marks for predators with curved teeth. Thylacosmilus atrox and Hoplophoneus primaevus both extinct big cats with shorter, thicker, and straighter teeth also performed well, according to the study.Seeking Evolutionary Advantages The common opossum and giant pandas teeth were among the poorest performers, requiring the most pressure to pierce the gelatin. Thats not surprising, since neither animal is known for its hunting skills.The tests help explain evolution among saber-toothed predators. There are at least five different examples of such teeth at different points in time. Those teeths ability to puncture yet not break definitely provided an advantage.The Peril of Over-SpecializationBut they could have also led to those animals demise. While that degree of specialization may have helped the big cats successfully hunt smaller mammals, it may have been a disadvantage as the climate changed. For instance, S. fatalis went extinct about 10,000 years ago, when the Ice Age glaciers began melting, which changed wildlife habitat.By combining biomechanics and evolutionary theory, we can uncover how natural selection shapes animals to perform specific tasks, said Pollock in the release. The study also suggests that saber-toothed animals fall on a spectrum of teeth shape and size. The conventional wisdom had divided the creatures into two categories based on tooth shape: dirk-toothed and scimitar-toothed. This study suggests that animals developed different hunting strategies over time.The team next intends to widen their analysis to include all tooth types, with the goal of better understanding biomechanical trade-offs between different shapes and sizes.The findings not only deepen our understanding of saber-toothed predators but also have broader implications for evolutionary biology and biomechanics, Professor Alistair Evans, a Monash University researcher and author of the paper said in a press release. Insights from this research could even help inform bioinspired designs in engineering.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.

Chimps are amazingly adaptable. Unlike other nonhuman primates, they live in a variety of habitats and have developed different behaviors to thrive in them. A recent study now shows that chimps also adjust genetically to environmentally specific challenges. Perhaps most notably, forest chimps have shown changes in the same genes known to help fight malaria in humans, according to a study in the journal Science. The study has implications for both chimp conservation and human health. The fact that we find potential evidence of parallel adaptations in chimpanzees and humans suggest that studying chimpanzee evolution (and primate evolution more generally) will help us learn not only about our closest living relatives but about our own evolution, says Aida Andrs, a genetics professor at University College London and an author of the paper. Learning About Chimp ResilienceIn terms of conservation, understanding genetic resilience could help predict how chimps respond to a warming world. Because many habitats are predicted to become drier, hotter and more seasonal due to climate change, this ecological diversity and adaptive response are particularly important not only for chimpanzees, but potentially also for other species living in the same territories and, more globally, other species in similarly changing habitats, says Andrs.In terms of health, comparing how the two species respond to pathogens like malaria could improve our understanding of infectious disease in both humans and chimps, since we share about 98 percent of the same DNA. The fact that we observe signatures of genetic adaptation in chimpanzees in the same genes that are known to confer some resistance to malaria in humans suggests that the two species may adapt very similarly, albeit independently, to the same infection, says Andrs.Capturing Genetic DifferencesHowever, we need to better understand how chimps genetically respond to diseases like malaria before strategies for humans based on chimp resistance can be developed. We also need to understand the sometimes subtle, but important, genetic differences between the similar chimp and human genes that appear to help both resist the disease. Andrs emphasizes that we dont know for certain that the genes they identified in chimps do indeed help them resist malaria only that they are similar to ones in humans that we know do that job. Evolutionary similarities arent certain to work biologically the same between two species.Even so, the research group took several steps to ensure they were capturing genetic differences from a wide variety of chimps. That started with gathering a lot of poop necessary to obtain DNA from the elusive animals without bothering them.That effort involved samples from 828 wild chimpanzees from 30 chimp groups (including four subspecies) from a variety of geographic and ecological environments. The subsequent genetic analysis of the protein-producing parts of the chimps genomes, representing the largest such effort on the species to date.The scientists compared the genetic information of chimps from different subspecies and environments and looked for variants that appeared more frequently in one environment versus another. For instance, they noticed that the forest chimps held differences in the genes associated with malaria resistance more so than other groups.Looking Both Forward and Backward Besides looking forward to see how both chimps and humans might adapt to various challenges, the group also intends to look backward at how early humans demonstrated their own resilience.What can chimpanzee genetic adaptation to the woodland-savannah tell us about the potential adaptations experienced by early modern humans as they moved from the deep forests to woodlands and then savannah, during human origins? says Andrs.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.

The patient told doctors he wasn't aware of ingesting any silver. Credit: New England Journal of MedicineShareDoctors at Prince of Wales Hospital in Hong Kong were at a loss after examining an 84-year-old man admitted for complications relating to an enlarged prostate. But medical experts werent perplexed by his prostate issuesthey were surprised at the patients unnaturally silver skin, fingernails, and even whites of his eyes.A subsequent skin biopsy revealed gray granules in the mans blood vessels, sweat gland membranes, hair follicles, and skin fibers. Further blood tests confirmed the hospital staffs suspicion: a silver concentration of 423 nmol/L, over 40 times the normal amount. The octogenarian was suffering from a rare case of generalized argyria, an oftenpermanent condition caused by a buildup of silver in the body.On physical examination, diffuse gray pigmentation of the skin, nails, and sclera was seen. A skin biopsy revealed small, dark granules in sweat glands. Credit: New England Journal of Medicine As Ars Technica explains, the New England Journal of Medicines recent case report, argyria occurs after a person ingests large quantities of silver over a prolonged period, during which time the metal particulates travel in their ionic form into the bloodstream. Eventually, the silver winds up in the tissues of the muscles, organs, skin, and possibly even the brain.Ingesting the silver isnt noticeable on its own. But after exposure to ultraviolet light (something that happens everyday thanks to the Sun), the metal ions turn into atomic silver and begin to oxidize into silver selenide and silver sulfide. This is what gives argyria patients their telltale blue-gray coloration. Their skin may darken even further thanks to silvers tendency to stimulate melanin production. Get the Popular Science newsletter Breakthroughs, discoveries, and DIY tips sent every weekday. By signing up you agree to our Terms of Service and Privacy Policy.Alternative medicine practitioners (and at least one cult) have long promoted taking doses of silver, either in capsule form or suspended in liquid known as colloidal silver. Doctors even sometimes prescribed it prior to the arrival of antibiotics. But as it stands today, there is no reliable evidence supporting the ingestion of silver to treat any health condition. If anything, too much silver can poison you and cause irreparable harm to your liver, kidneys, and bone marrow. In some cases, it can kill you.In the case of the octogenarian in Hong Kong, however, the cause of his argyria remains a mystery. He reportedly only took the finasteride prescribed to him by doctors for his prostate, and did not admit to regularly or purposely ingesting silver. And because he spent a career waiting tables, job-related exposure seemed unlikely, as well. No one else in his apartment building displayed similar symptoms, either. Doctors eventually discharged the mysteriously silver man from the facility with a referral for additional toxicological tests.But whether or not anyone ever gets to the bottom of his malady, at least let it serve as a valuable reminder to never take silver home remedies.

Skip to contentExtreme Climate UpdateClimate2024 was Earths hottest year on record, passing a dangerous warming thresholdIts the first time the average temperature topped 1.5 degrees Celsius above preindustrial levels Almost everywhere around the globe, it was hotter than the average from 1991 to 2020. In some places, such as the Canadian Arctic, temperatures were as much as 5 degrees Celsius (the darkest red) higher. Blue colors mark the few regions where temperatures were cooler than the average.ERA5. Credit: C3S / ECMWF.By Carolyn Gramling1 minute agoIts official: The year 2024 was indeed the hottest on record. It was also the first year in recorded history that Earths average temperature was higher than 1.5 degrees Celsius above preindustrial levels.Scientists outlined those grim milestones in a report released January 10 by the European Unions Copernicus Climate Change Service. Multiple other global records were smashed throughout 2024, the researchers noted, including for atmospheric greenhouse gas levels, air temperatures and sea surface temperatures.

The enormous near-Earth asteroid (887) Alinda has made its closest approach to our planet in decades, and it's about to peak in brightness in a rare once-in-a-decade event. Here's how to watch it live this weekend.

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