Super-female bearded dragons 'more male than males' - Science News. Updated When is a female a female? And when is a male a male? These are the questions that scientists continue to ponder after the latest research on an Australian lizard that reverses its sex when exposed to high incubation temperatures. Key points Incubation temperature can create female lizards with male chromosomesThese lay more eggs than standard femalesThey are also bolder in their behaviour than the average maleThis strange combination could provide them with an advantage The study shows central bearded dragons (Pogona vitticeps) that are born with male chromosomes, but can lay eggs, have other strange characteristics. Not only, as found previously, do they behave like super females, laying more eggs than standard females, but they are also bolder and more active than males.
Male bearded dragons usually have two Z chromosomes and females usually have a Z and a W chromosome. Eleven of the dragons studied previously were sex-reversed females, in other words, females with ZZ chromosomes. Melbourne Aquarium celebrates birth of 45 weedy sea dragons, 'Marcel Marceau' of the ocean. Updated Melbourne Aquarium is celebrating the survival of 45 newborn weedy sea dragons, which are difficult to breed and rear in captivity. The animals, which are the marine emblem of Victoria, were born in December and are part of the aquarium's fourth breeding program since 2005. Listed as a threatened species, the sea dragons are found in the waters surrounding southern Australia.
After the female lays her eggs, the male looks after them under its tail for two months until they hatch. Melbourne Aquarium's exhibit manager Teresa Todd said the offspring were a surprise. "We didn't expect it; it just kind of happened, and the ball has basically kept rolling and we've done really well," she said. Not many people would know about these sea creatures at our doorstep. Ms Todd said keeping the animals was a challenge and the aquarium used tanks especially designed to replate water flows similar to the sea dragon's natural habitat. Ms Todd said there was a lot of interest in the animal. Baby fish may get lost in silent oceans as carbon dioxide rises - Science. Posted Future oceans will be much quieter places, making it harder for young marine animals that navigate using sound to find their way back home, new research has found.
Under acidification levels predicted for the end of the century, fish larvae will cease to respond to the auditory cues that present-day species use to orient themselves, scientists reported in the journal Biology Letters. While ocean acidification is known to affect a wide range of marine organisms and processes such as smell, until now its effect on marine soundscapes and impact on the larvae of marine animals was unknown. The ocean is filled with sounds that carry information about location and habitat quality, study co-author Sir Ivan Nagelkerken said. [Animals] that rely on sound as an orientation cue will be heavily impacted, limiting their ability to survive and contribute to the population.
Associate Professor Sir Ivan Nagelkerken "This natural laboratory gave us a peek into the future," Dr Nagelkerken said. Polar bears will die out if global warming is not reversed, US report finds - Climate Change - Environment. In a draft recovery plan for polar bears produced by the US Fish and Wildlife Service, it says: "The single most important step for polar bear conservation is decisive action to address Arctic warming. " "Short of action that effectively addresses the primary cause of diminishing sea ice, it is unlikely that polar bears will be recovered. " Polar bears eat, mate and give birth on sea ice. Greenhouse gas emissions contribute to global warming, which is reducing the levels of summer sea ice in the Artic. No sea ice means polar bears will struggle to survive.
If global warming and sea ice depletion is to be addressed, it will require global action, the report says. Loading gallery In pictures: Biggest threats to the rainforests 1 of 10 The worldwide polar bear population is estimated to be between 20,000 and 25,000. Another report, produced by the US Geological Survey, predicted the fate of the species in possible future scenarios.
Global seabird decline greater than expected › News in Science (ABC Science) News in Science Wednesday, 17 June 2015 Anna SallehABC Seabird dive The global seabird population may have fallen by almost 70 per cent since 1950, a new study suggests. The study, published recently in PLOS ONE, analysed data on 162 species, representing 19 per cent of the global seabird population. They found the population of those species had declined overall by 69.7 per cent between 1950 and 2010. "It's an awful lot," says co-author ecologist Dr Edd Hammill of the University of Technology, Sydney. "The level of decline is considerably greater than what we were expecting. " The researchers argue this finding can be extrapolated to the global seabird population because the sample used was large and all the world's ecosystems were represented. "Every continent is represented, every coastline of every continent is represented as well," says Hammill.
Hammill says a "back of the envelope" calculation suggests over a billion birds have been lost globally during the study period. 100-Year-Old Turtle, the Last of Her Kind, Could Soon Be a Mom - Extinction Countdown - Scientific American Blog Network. I have written about a lot of causes of extinction over the years. Climate change. Disease. Overhunting. Pollution. The list goes on and on. Well here’s a new one that could end up on the list: a mangled penis. Now, normally a single set of damaged sexual organs wouldn’t make that much of a difference in the grand scheme of things. No one knows how long these two turtles will live, but time is obviously of the essence. Collecting a sample of his little swimmers proved...challenging. Alas, neither of those methods worked. The researchers anesthetized the turtle. Long story short, they got their sample and not long after the female met her new boyfriend, Mr.
Now the waiting begins. Then we wait again to see if the eggs hatch. The next step, many moons from now, would be to get any newborns to also breed and further expand the species. Photos by Gerald Kuchling, courtesy of the Wildlife Conservation Society. First 'virgin birth' fish found in the wild › News in Science (ABC Science) News in Science Tuesday, 2 June 2015 Dani CooperABC Survival strategy An endangered species of fish can produce offspring without mating, report US researchers.
The discovery, published today in Cell Biology , is the first-known example of the asexual reproductive process known as parthenogenesis to have been uncovered in the wild. 'Virgin births' in the smalltooth sawfish (Pristis pectinata) may be triggered by the population's dwindling numbers, report the researchers. The smalltooth sawfish is a large, critically endangered ray that is estimated to have declined to 1-5 per cent of its population size since 1900. Between 2004 and 2013, 190 individuals ranging in total length from 67.1 centimetres to 3.81 metres were sampled, tagged, and released in the Caloosahatchee River, Peace River and Ten Thousand Islands regions.
"What the DNA fingerprints told us was altogether more surprising: female sawfish are sometimes reproducing without even mating. " Tags: animals, animal-behaviour, fish. Rapidly evolving lizards show how some creatures can adapt to beat climate change. Lizards from the deserts of Australia to the tops of mountains in Costa Rica have given us insights into how animals take advantage of their environment to be less cold-blooded. Lizards seek out sunny patches or the warm underside of rocks where they can soak up the heat to enhance digestion or run faster.
When it gets too hot, they can escape the heat by finding shade or retreating to burrows underground. In particular, tropical species, including lizards, are thought to be especially vulnerable to climate warming because they already live at temperatures that can be dangerous. Without the sweat glands or metabolic control that mammals take for granted, lizards can heat up very quickly if they find themselves caught out in the sun for too long. Species living in the tropics are also thought to have behavioural adaptations that are finely tuned to stable and predictable weather regimes, such as daily activity rhythms. Speedy lizards Evolution in fast-motion? Evolution as conservation. Sea Turtle Conservancy :: Presentations at the Annual International Sea Turtle Symposium. Sea turtles use magnetic fields to find their birth place, researcher believes. By Isobel Roe Posted Adult sea turtles use the Earth's magnetic field to return to nest on the same beach they were born on, a researcher believes.
PhD candidate Roger Brothers, from the University of North Carolina, said while the phenomenon of animals using a magnetic field to navigate was not uncommon, very few animals used it to find their way home. He said it raised concerns about wire used by conservationists along Queensland's Great Barrier Reef to keep animals and people away from unhatched eggs, fearing it could interfere with a turtle's perception of the magnetic signature. "The new findings that we're presenting provide evidence that nesting females relocate those natal beaches by seeking out the unique magnetic signatures along the coast and implies that hatchling turtles are learning those fields when they're young and using that information to return as adults," Mr Brothers said.
However, it was not yet known how the turtles detect magnetic fields.