433 news posts in Life sciences

Life sciences

13 Nov 2023

Endangered turtle population under threat as pollution may lead to excess of females being born

By Mischa Dijkstra, Frontiers science writer Researchers from Australia studied the influence of pollution on the sex ratio of clutches of sea green turtles. This species is at risk of extinction from a current lack of male hatchlings. They concluded that exposure to the heavy metals cadmium and antimony, accumulated by the mother and transferred to her eggs, may cause embryos to be feminized. Pollution may thus compound the female-biasing influence of rising global temperatures on green sea turtles. Green sea turtles, Chelonia mydas, are listed as endangered on the IUCN Red List of Threatened Species. They are at risk of extinction due to poaching, collisions with boats, habitat destruction, and accidental capture in fishing gear. But another threat, linked to climate change, is more insidious: sea turtles have temperature-dependent sex determination, which means that more and more embryos develop into females as temperatures keep rising. Already, in the northern part of the Great Barrier Reef off Australia, hundreds of females are born for every male. Now, researchers have shown that the resulting risk of extinction due to a lack of male green sea turtles may be compounded by pollution. Dr Arthur Barraza, a researcher at the Australian Rivers Institute […]

Life sciences

13 Oct 2023

Caution, ocelot crossing: special wildlife exits on busy roads help protect endangered cat

By Mischa Dijkstra, Frontiers science writer Texas ocelot, Leopardus pardalis albescens. Image credit: Kline Lab, University of Texas Rio Grande Valley Traffic collisions are a major cause of death of endangered Texas ocelots. Researchers have now shown that recently designed wildlife exits, meant to allow ocelots to leave highways surrounded by fences, function as they are designed to do. 10 mammal species apart from ocelots learned to use them correctly. The authors concluded that these exits are a useful conservation measure in Texas, not only for ocelots. The Texas ocelot (Leopardus pardalis albescens) is endangered due to historic hunting, habitat loss, inbreeding, and traffic collisions. Today, only between 50 and 80 ocelots remain in the US, exclusively in Willacy and Cameron counties in southern Texas. These two populations are isolated from the larger one in northwestern Mexico by highways and urban development. “Here we show that a range of species, including middle-sized carnivores such as bobcats and coyotes, successfully use wildlife exits, a new type of mitigation structure specifically designed for the US endangered ocelot,” said first author Zarina Sheikh, a former graduate student at the University of Texas Rio Grande Valley, about their new study in Frontiers in Ecology […]

Life sciences

11 Oct 2023

Peregrine falcons set off false alarms to make prey easier to catch

by Angharad Brewer Gillham, Frontiers science writer Image: US Fish and Wildlife Service Pacific Southwest Region, public domain Can clever predators manipulate prey into taking bigger risks, making them easier to hunt? Scientists have found that, by carrying out attacks which force Pacific dunlins into exhausting evasive maneuvers, peregrine falcons increase the likelihood of successfully hunting those dunlins later. The prey birds are tired out or forced to forage at more dangerous times. Predators must eat to survive — and to survive, prey must avoid being eaten. One theory, the Wolf-Mangel model, suggests predators could use false attacks to tire prey out or force them to take bigger risks, but this has been hard to show in practice. Now, scientists observing peregrine falcons have found evidence that they deliberately exhaust their prey to improve later hunting success. “Although predators are imagined as clever in novels and movies, like the velociraptors in Jurassic Park, empirical biologists are generally not inclined to give much credence to such ideas,” said Dr Ronald Ydenberg of Simon Fraser University, lead author of the study in Frontiers in Ethology. “I have often been puzzled when watching raptors by aspects of their behavior, such as prominent perching […]

Life sciences

29 Sep 2023

Mouthwash for dogs: water additive with pomegranate helps to keep canine teeth healthy

By Mischa Dijkstra, Frontiers science writer Veterinarian researchers performed a blinded randomized controlled trial to show that a commercially available water additive with pomegranate extract is effective in limiting the reformation of plaque and tartar on the teeth of dogs after a professional dental cleaning. This could help to prevent periodontal disease in the long term. Periodontal disease is one of the most common canine diseases, affecting at least 80% of dogs aged three and over. Periodontal disease begins as gingivitis, where gums become red and inflamed, and may bleed. Untreated, the disease can progress to periodontitis, where the alveolar bone is progressively damaged so that teeth may loosen or fall out. In turn, periodontitis is a risk factor for other diseases like cardiovascular and lung disease. A major cause of periodontal disease is poor oral hygiene, which can lead to the build-up of plaque and tartar. For this reason, veterinarians counsel owners to brush their dogs’ teeth regularly. Unfortunately, compliance with this advice is low, because it’s onerous or because some dogs won’t cooperate. “Here we show that an additive to drinking water, based on pomegranate extract, can reduce the accumulation of plaque and tartar in dogs,” said Dr […]

Life sciences

20 Sep 2023

Shading the Great Barrier Reef from the sun might slow bleaching-induced coral decline

By Deborah Pirchner, Frontiers science writer Image: Shutterstock As ocean temperatures rise, corals can lose their color due to heat stress. Bleaching does not kill corals immediately, but they become more vulnerable to disease and starvation. Shading reefs by covering them with cloth or fog, can protect them from excessive heat. Now, researchers have tested the shading response of two coral species and found that four hours of shade during the hottest time of the day can significantly slow bleaching. This knowledge can help with solar radiation management in marine ecosystems, including the Great Barrier Reef. Over the past two decades, coral reefs have declined at unprecedented rates. This is in part because of extreme weather events, which cause wide-spread coral bleaching, a process during which corals lose their color because of stressors, including changes in water temperature, light, or nutrient availability. One of the worst mass bleaching events occurred in 2016 and 2017 on the Great Barrier Reef, causing bleaching on 91% of the system’s reefs. As frequency and severity of mass bleaching events are expected to increase in the future, researchers are looking for ways to protect corals from excessive radiation and temperatures. As part of the Cooling […]

Life sciences

25 Aug 2023

Reefs made from culled trees can help kickstart sea life in threatened waters

By Mischa Dijkstra, Frontiers science writer One of the ‘tree-reefs’ being examined after five months in the Wadden Sea. Image credit: Jon Dickson Researchers have shown that structures made from culled pear trees sunk into soft-bottomed seas like the Dutch Wadden Sea provide excellent replacements for naturally occurring hard substrates, of which many have been lost due to human activities. These ‘tree-reefs’ were rapidly colonized and became hotspots for fish, crustaceans, polyps, and shellfish. Reefs, whether natural or man-made, are hotspots of marine biodiversity. But especially in soft-bottomed seas, reefs have now become scarce because many hard substrates have been removed due to overfishing of shellfish, dredging, trawling, and deep-sea mining. How can we restore this lost biodiversity, as encouraged by the UN Decade on Ecosystem Restoration (2021-2030) and the EU Biodiversity Strategy? Now, researchers have shown that culled fruit trees sunk into the sea are a cheap and effective way to recreate reefs and boost the local diversity and abundance of marine life. The study, published in Frontiers in Marine Science, was done in the Wadden Sea, a UNESCO World Heritage Site and the largest tidal flats system in the world. “Here we show that native marine […]

Life sciences

22 Aug 2023

City-living may make male song sparrows more doting ‘super’ fathers

By Deborah Pirchner, Frontiers science writer Image: Rob Lachlan New behavioral traits are often the first response of animals to changing environmental conditions. As cities increasingly become habitats of wildlife, researchers have studied behavioral changes in birds and examined how urbanization impacts parental care behavior of male song sparrows. The team found that in cities, where male song sparrows are known to be more aggressive than in rural surroundings, male birds visited nests more often than rural conspecifics visited countryside nests. When animals settle in new environments, or when their natural habitats are rapidly changed by human influence, their behaviors change. One such behavioral change that has been observed in several bird species that settled in cities is increased aggression, born out of the need to defend territories. City-living sparrows have, due to lower species density, fewer encounters with their kin than in the countryside. Yet, urban song sparrows have been shown to be consistently more aggressive in defending their territories. Now, a team of researchers in the US has investigated the effects of urbanization and the associated increase in male aggression on the parental care provided by male birds. “Male songbirds in temperate zones are thought to reduce […]

Life sciences

31 Jul 2023

Scientists solve ‘enigma’ of pygmy right whales’ feeding habits

By Mischa Dijkstra, Frontiers science writer A pygmy right whales in the wild. Image credit: Henry Cordell Researchers have shown from stable isotope ratios in the baleen of pygmy right whales that this ‘most enigmatic’ species of baleen whales remains in waters off southern Australia year-round and feeds on Australian krill and copepods. Unlike larger relatives, they don’t make seasonal migrations to Antarctic regions. Pygmy right whales (Caperea marginata) are the smallest, ‘most enigmatic’, and probably least studied of all baleen whales. Baleen act like sieves in the mouth of baleen whales, which allow seawater to pass but trap small prey items like zooplankton and small fish. Pygmy right whales are rarely seen in the wild. Reason for this may be their relatively small size – up to 6.5 meters long and weighing up to 3.5 tons –, sparse distribution, and inconspicuous behavior, especially compared to the boisterous humpback whales. Historically, whalers rarely bothered hunting them. The little we know about them is mainly based on beached animals. “Here we show that pygmy right whales don’t behave like most other baleen whales: they don’t make long cross-ocean migrations,” said Dr Tracey Rogers, a professor of ecology and evolution at the […]

Life sciences

06 Jul 2023

Stressed rattlesnakes found to calm down in the company of a nearby ‘friend’

By Deborah Pirchner, Frontiers science writer Image: Jasper Nance/Flickr (CC BY-NC-ND 2.0) When a creature’s stress levels decrease because of the presence of a companion, it is known as social buffering. In highly social animals, such as mammals and birds, this phenomenon is well studied. Now, researchers have examined social buffering in rattlesnakes and found that the presence of a second snake significantly reduced rattlesnakes’ change in heart rates after they experienced disturbance. It is the first evidence of social buffering in reptiles. When animals suffer from acute or chronic stress, they produce more hormones causing shifts in the nervous system, immune response, and behavior. Some animals, if they are in the presence of a conspecific, can modulate their response to buffer stress. This is known as social buffering. There is some research suggesting that snakes can exhibit complex social behavior. Nevertheless, social buffering in reptiles, as well as in other asocial organisms and solitary foragers, hasn’t been studied extensively. Now, researchers in the US have examined if rattlesnakes inhabiting Southern California use social buffering to alleviate acute stress. “We showed that when two snakes were together and experienced a stressful situation, they could buffer each other’s stress response, much […]

Life sciences

05 Jul 2023

Migrant orangutans learn which foods are good to eat by watching the locals

By Mischa Dijkstra, Frontiers science writer An unflanged migrant orangutan male (on the left side) and an adolescent local orangutan female (on the right side) are peering at each other. Orangutan species: Pongo abelii. Image credit: Caroline Schuppli, SUAQ Project, http://www.suaq.org Researchers analyzed 30 years of observations on a total of 152 male migrant orangutans on Sumatra and Borneo and showed evidence that migrants learn about unfamiliar foods in their new home range by ‘peering’ at experienced locals: intensely observing them at close distance. Peering was most frequently seen when locals consumed foods that were rare or hard to process Orangutans are dependent on their mothers longer than any other non-human animal, nursing until they are at least six years old and living with her for up to three years more, learning how to find, choose, and process the exceedingly varied range of foods they eat. But how do orangutans that have left their mothers and now live far from their natal ranges, where the available foods may be very different, decide what to eat and figure out how to eat it? Now, an international team of authors has shown that in such cases, migrants follow the rule ‘observe, and […]

Life sciences

30 May 2023

Humans evolved to walk with an extra spring in our step

by Angharad Brewer Gillham, Frontiers science writer Image/Shutterstock.com Scientists have discovered that the recoil created by the flexible arch of human feet helps position our legs in the optimal posture for moving forward in bipedal walking. Understanding how our joints help modern humans walk upright could help us track the evolution of bipedalism and improve care for patients with foot problems. A new study has shown that humans may have evolved a spring-like arch to help us walk on two feet. Researchers studying the evolution of bipedal walking have long assumed that the raised arch of the foot helps us walk by acting as a lever which propels the body forward. But a global team of scientists have now found that the recoil of the flexible arch repositions the ankle upright for more effective walking. The effects in running are greater, which suggests that the ability to run efficiently could have been a selective pressure for a flexible arch that made walking more efficient too. This discovery could even help doctors improve treatments for present-day patients’ foot problems. “We thought originally that the spring-like arch helped to lift the body into the next step,” said Dr Lauren Welte, first author […]

Life sciences

26 May 2023

Termite mounds reveal secret to creating ‘living and breathing’ buildings that use less energy

By Mischa Dijkstra, Frontiers science writer Macrotermes termite mound in Namibia. Image credit: D. Andréen Scientists studied the ‘egress complex’ of Macrotermes michaelseni termites from Namibia, which appears to promote moisture regulation and gas exchange. They showed that the layout of this lattice-like network of tunnels can intercept wind around the termite mound to create turbulence inside, which can power ventilation and control the interior climate. These properties can be copied to create a comfortable climate in human buildings with little energy. Among the approximately 2,000 known species of termites, some are ecosystem engineers. The mounds built by some genera, for example Amitermes, Macrotermes, Nasutitermes, and Odontotermes, reach up to eight meters high, making them some of the world’s largest biological structures. Natural selection has been at work improving the ‘design’ of their mounds over tens of millions of years. What might human architects and engineers learn if they go to the termites and consider their ways? In a new study in Frontiers in Materials, researchers showed how termite mounds can teach us to create comfortable interior climates for our buildings that don’t have the carbon footprint of air conditioning. “Here we show that the ‘egress complex’, an intricate network […]

Life sciences

09 May 2023

Can lions coexist with cattle in Africa?

by Laurence G Frank/Deborah Pirchner, Frontiers science writer Image: Shutterstock Protecting lions and the interests of cattle producers in Kenya is a difficult balancing act. In a recent Frontiers in Ecology and Evolution article, Dr Laurence G Frank, a researcher at the Museum of Vertebrate Zoology at the University of California, Berkeley, and the Mpala Research Centre in Laikipia, Kenya, explored how protecting livestock can help protect endangered lions. As part of our Frontiers Scientist series, Frank, who also is the director of Living With Lions, a conservation research group working in nonprotected areas of Kenya to save the remaining wild lions and other predators outside National Parks, caught up with Frontiers to tell us about his career and research. What inspired you to become a researcher? All children love animals and some who never grow up become zoologists. At the age of 10 I was introduced to field biology at a local community museum, where we were taught basic ecology and animal behavior, collecting and specimen preparation technique, and formal field note format. My weekends were spent pestering local reptiles and trapping small mammals in the Bay Area hills; many of my juvenile specimens are in the California Academy of Sciences […]

Life sciences

05 May 2023

Secret behind Amazonian ‘dark earth’ could help speed up forest restoration across the globe

By Mischa Dijkstra, Frontiers science writer Researchers from Brazil showed that Amazonian dark earth (ADE), soils enriched by Amerindian people thousands of years ago, increases the establishment and growth of seedlings of tree species important for reforestation. By copying the composition of ADE, especially its microbes, reforestation in Brazil and elsewhere could be sped up Between approximately 450 BCE and 950 CE, millions of Amerindian people living in today’s Amazonia transformed the originally poor soil through various processes. Over many human generations, soils were enriched with charcoal from their low-intensity fires for cooking and burning refuse, animal bones, broken pottery, compost, and manure. The result is Amazonian dark earth (ADE) or terra preta, exceptionally fertile because rich in nutrients and stable organic matter derived from charcoal, which gives it its black color. Now, scientists from Brazil show that ADE could be a ‘secret weapon’ to boost reforestation – not only in the Amazon, where 18% or approximately 780,000 km2 has been lost since the 1970s – but around the world. The results are published in Frontiers in Soil Science. “Here we show that the use of ADEs can enhance the growth of pasture and trees due to their high levels […]

Life sciences

28 Apr 2023

Old dogs with dementia sleep less deeply, just like people with Alzheimer’s

By Mischa Dijkstra, Frontiers science writer Scientists have shown that old dogs with canine dementia have sleep and brain wave patterns that mirror those found in people with Alzheimer’s. This is the first study to use polysomnography techniques from human sleep studies in old dogs In people with Alzheimer’s, the earliest symptoms are commonly disruptions in sleep rhythms. These include daytime sleepiness, showing agitation or confusion around dusk, staying awake longer, and waking up often at night. They are thought to result from damage to sleep-regulating areas in the brain. Alzheimer patients tend to spend less time in both REM (rapid eye movement) sleep, in which most dreaming occurs, and non-REM (NREM) sleep. But they show the greatest reduction in so-called slow-wave sleep (SWS) – a stage of non-dreaming deep sleep, characterized by slow ‘delta’ brain waves (0.1 to 3.5 Hz) – when day-time memories are consolidated. Now, scientists have shown that the same reduction in SWS and delta brain waves occurs in dogs with the canine equivalent of dementia, canine cognitive dysfunction syndrome (CCDS). These dogs thus sleep less and less deeply. The results are published in Frontiers in Veterinary Science. “Our study is the first to evaluate the […]