Category: NWT_Animals

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G24 INSTA NWT_Animals Research

Tortoise beats the hare every time in race of life, study says

“The fable of ‘The Tortoise and the Hare’ is a metaphor about life, not a story about a race,” said Adrian Bejan, a Duke University professor who led a recent study on animal speed. “We see in animal life two starkly different lifestyles—one with nearly steady feeding and daily sleep and another with short bursts of intermittent feeding interspersed with day-long siestas. Both of these patterns are the rhythms of living that Aesop taught.”

Bejan examined the reported speeds of animals based on air, water, and land data. The results reveal that some of the fastest animals in the world are actually the slowest in terms of average speed throughout their lifetime.

And apparently, this result is also reflected in the aviation industry, where the general pattern is that speed and size increase hand-in-hand.

The only exception is the jet fighter, which although faster than others in short bursts, spends most of its time on the ground. And across their lifetime, they are very slow compared to transport models.

The study was created following a previous paper that utilized Bejan’s constructal theory to show that animals’ speed tends to rise with body mass.

“When I would give speeches on this topic, somebody would always bring up outliers to this principle such as the cheetah as counterexamples,” Bejan said. “But this study shows that these ‘outliers’ are to be expected and, when looked at over their lifetimes, are not so different from their lumbering cousins after all.”

The findings were published in Scientific Reports.

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G24 INSTA NWT_Animals NWT_Biology Research SCI TECH

Study suggests narwhals and beluga whales experience menopause

A team of scientists discovered that narwhals and beluga whales experience menopause, which brings the total number of species known to experience the process to five. Humans aside, the species known to experience menopause all belong to the toothed whale parvorder.

“For menopause to make sense in evolutionary terms, a species needs both a reason to stop reproducing and a reason to live on afterwards,” said Sam Ellis of the University of Exeter, first author of the study. “In killer whales, the reason to stop comes because both male and female offspring stay with their mothers for life—so as a female ages, her group contains more and more of her children and grandchildren.”

“This increasing relatedness means that, if she keeps having young, they compete with her own direct descendants for resources such as food,” he added.

“The reason to continue living is that older females are of great benefit to their offspring and grand-offspring. For example, their knowledge of where to find food helps groups survive.”

More than four decades of intense study has documented the existence of menopause in killer whales.

“It’s hard to study human behaviour in the modern world because it’s so far removed from the conditions our ancestors lived in,” said Darren Croft, senior author of the study. “Looking at other species like these toothed whales can help us establish how this unusual reproductive strategy has evolved.”

Despite the fact that many individuals in various species fail to reproduce later in life, the team looked for evidence that suggested an “evolved strategy” where females had a post-reproductive lifespan.

The findings were published in Scientific Reports.

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Archaeology G24 INSTA NWT_Animals SCI

Researchers just discovered a fossilized turtle with no shell

Researchers just discovered a turtle fossil from 228 million years ago that doesn’t have a shell. Interestingly, the unique new species did possess a toothless break, which is a key turtle characteristic.

The new species is named Eorhynchochelys sinensis, which means “dawn beak turtle from China,” since it’s believed to be the first turtle with a beak. It also possesses a body in the shape of a Frisbee with wide ribs. However, these ribs did not contribute to the formation of the shell common in modern turtles.

“This creature was over six feet long, it had a strange disc-like body and a long tail, and the anterior part of its jaws developed into this strange beak,” said Olivier Rieppel, co-author of the study. “It probably lived in shallow water and dug in the mud for food.”

And since it was able to develop a beak prior to other turtles, the species is an example of mosaic evolution, which is when traits evolve independently and at different times.

“This impressively large fossil is a very exciting discovery, giving us another piece in the puzzle of turtle evolution,” said Nick Fraser, co-author of the study. “It shows that early turtle evolution was not a straightforward, step-by-step accumulation of unique traits but was a much more complex series of events that we are only just beginning to unravel.”

“With Eorhynchochelys’s diapsid skull, we know that turtles are not related to the early anapsid reptiles, but are instead related to evolutionarily more advanced diapsid reptiles. This is cemented, the debate is over,” Rieppel said. “Eorhynchochelys makes the turtle family tree make sense. Until I saw this fossil, I didn’t buy some of its relatives as turtles. Now, I do.”

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Archaeology G24 INSTA NWT_Animals SCI

Amateur fossil hunter discovers teeth of ancient shark

An amateur fossil hunter just discovered the fossils of an ancient mega-shark believed to be the close cousin of the megalodon. The remains were found on a beach in Australia and will be revealed at the Museums Victoria.

The teeth are approximately three inches long and stem from the Great Jagged Narrow-Tooth Shark, an extinct species of mega-shark that roamed the seas of Australia approximately 25 million years ago. The shark can grow as long as 30 feet, which is twice the size of a great white shark.

The discovery was made by amateur fossil finder Philip Mullaly, who is also a teacher in Australia. He found the fossils during a walk through a fossil site on the Victoria coast.

“I was walking along the beach looking for fossils, turned and saw this shining glint in a boulder and saw a quarter of the tooth exposed,” he said. “I was immediately excited, it was just perfect and I knew it was an important find that needed to be shared with people.”

Mullaly contacted Erich Fitzgerald, the senior curator of vertebrae paleontology at Museums Victoria, and offered to donate them.

“These teeth are of international significance, as they represent one of just three associated groupings of Carcharocles angustidens teeth in the world,” Fitzgerald explained.

“By donating his discovery to Museums Victoria, Phil has ensured that these unique fossils are available for scientific research and education both now and for generations to come,” he continued. This is absolutely essential for documenting and preserving Australia’s prehistoric history.”

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Archaeology NWT_Animals SCI

Baby snake from dinosaur age found frozen in amber

For the first time ever, scientists discovered an ancient snake embryo contained in 105-million-year-old amber. The discovery reveals important information on the evolution of modern snakes.

“This snake is linked to ancient snakes from Argentina, Africa, India and Australia,” said paleontologist Michael Caldwell, lead author of the study and professor in the Department of Biological Sciences. “It is an important—and until now, missing—component of understanding snake evolution from southern continents, that is Gondwana, in the mid-Mesozoic.”

Caldwell and his team, which includes researchers from China, Australia, and the United States, tracked the migration of the ancient Gondwanan snakes all the way back to 180 million years ago when they were transported by tectonic movements created by continents and their parts.

The team also gained information from the amber fragment that encased the specimen.

“It is clear that this little snake was living in a forested environment with numerous insects and plants, as these are preserved in the clast,” Caldwell said. “Not only do we have the first baby snake, we also have the first definitive evidence of a fossil snake living in a forest.”

The team used computerized tomography (CT) scans to study the ancient snake and compare it with the children of modern snakes, shedding light on the embryology and development of the ancient specimen.

“All of these data refine our understanding of early snake evolution, as 100-million year-old snakes are known from only 20 or so relatively complete fossil snake species,” Caldwell said. “There is a great deal of new information preserved in this new fossilized baby snake.”

The findings were published in Science Advances.

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NWT_Animals Research SCI

New model identifies main factors that shaped evolution

A new computer simulation takes into account the numerous factors that drive evolutionary extinction and adaptation. The study outlining the model attempts to bring us closer to understanding the complex interactions between climate change and topography, and how these interactions affect the biodiversity and evolutionary histories of species in their natural ecosystems.

“We had hoped to be able to model in the simulation the most fundamental processes that shape the geography of life on Earth,” said Robert Colwell, who led the research with Brazilian colleague Thiago F. Rangel in collaboration with Neil Edwards and Philip Holden in the United Kingdom.

To create their model, the team looked to South America, which is the most biologically diverse continent on the planet. And since the Andes mountain range started developing 25 million years ago, it created an extremely varied landscape that gave rise to a plethora of biodiversity, making it a perfect area to study the evolution and ecology of biodiversity.

“The Andes are the longest mountain range on Earth, and the only trans-tropical one,” Rangel said. “They sit right beside the Amazon, the planet’s largest tropical rainforest and river basin. This is the reason South America has such exuberant biodiversity.”

“Our results demonstrate how intimately the evolution of life depends on the changing physical environment,” said Neil Edwards of The Open University modelling team.

The model comes at a time of unprecedented climate change, highlighting the unique and dynamic power of climate change and the many ways it shapes the evolution of life on Earth.

“The current pace of human driven climate change is much, much faster than anything in our model, but the same processes are happening in terms of species’ range shifts today,” Colwell said.

The findings were published in Science.

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NWT_Animals Research SCI

Genetic legacy of first dogs lives on in sexually transmitter cancer

A new study suggests that the domesticated dogs that firsts traveled to the Americas were brought by humans that were migrating from Asia. And although they were eventually wiped out in the 15th century, their genetic legacy appears to live on as a sexually transmitter cancer.

The cancer is called canine transmissible venereal tumor (CTVT) and has spread around the world. It is essentially a mutated version of animal DNA, which was traced back to the first domesticated American dogs.

“It’s quite incredible to think that possibly the only survivor of a lost dog lineage is a tumor that can spread between dogs as an infection,” said Maire Ní Leathlobhair, a researcher from the Department of Veterinary Medicine at the University of Cambridge and co-lead author of the study.

Although the examination into the genetic history of dogs is far from finished, the new data sheds light on more clues.

“I think it’s an important technical achievement to get more ancient dog genomes,” said Krishna Veeramah, a geneticist at Stony Brook University who has studied ancient dog evolution. He also claims that until now, we have only sequenced the nuclear DNA of three other breeds of ancient dog.

“While the study does not really address the ultimate origins of dogs from wolves (this will need older samples from Eurasia), it sheds new light on an important aspect of dog-human history,” he said.

Ultimately, the new data will add to our current archaeological and genetic research and continue painting a picture of the history of the world’s most iconic domestic animals.

The findings were published in Science.

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Archaeology NWT_Animals SCI

‘First giant’ dinosaur fossil discovered in Argentina

Researchers just discovered the “first giant” dinosaur fossil in Argentina, which should shed light on evolutionary process that helped dinosaurs become some of the largest creatures to ever traverse the Earth. Researchers are calling the discovery “a huge evolutionary finding.”

“We could see that it was a new species that we named Ingentia prima,” said Cecilia Apaldetti, first author of the study from the Universidad Nacional de San Juan in Argentina.

The fossil in question dates all the way back to the Triassic period approximately 30 million years prior to the arrival of the long-neck Jurassic Brachiosaurus. Scientists believe that the finding is important because it reshapes the conversation surrounding dinosaur evolution.

“We used to think that the first giant dinosaurs arose in the early part of the Jurassic Period, after supervolcanoes caused a global extinction at the end of the Triassic,” Steve Brusatte of the University of Edinburgh, who wasn’t involved in the study, said in a BBC analysis. “But the lessemsaurids tell us that at least some dinosaurs were able to attain giant sizes during the latest part of the Triassic, before the extinction.”

Before the discovery, researchers believed that Triassic dinosaurs were significantly smaller in size..

“What is really unexpected is that the lessemsaurids achieved their huge bodies independently of the gigantic sauropods like Brontosaurus and Diplodocus, which did indeed evolve later during the Jurassic,” Brusatte said in his BBC analysis.

“The development of huge size wasn’t just a one-off event for the sauropods, but rather different types of dinosaurs were able to become colossal, which speaks to just how incredible these animals were,” he added.

The findings were published in Nature Ecology and Evolution.

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NWT_Animals NWT_Biology SCI TECH

Extinct cave bear DNA discovered in living bears

A new study discovered that approximately 0.9 to 2.4 percent of living brown bears’ DNA can be traced back to the extinct cave bears species, which died out approximately 24,000 years ago.

The discovery is the second time that scientists have discovered the DNA of extinct ice-age creatures in living relatives.

“By any standard definition, [cave bears] are extinct, but it doesn’t mean that their gene pool is erased, because they continue to live on in the genomes of these living animals,” said Axel Barlow, a postdoctoral researcher at the University of Potsdam and one of the lead authors of the study.

The data also suggests that some species interbreed regularly. For example, the DNA of Tibetan cattle and yak exhibit signs of interbreeding.

“The old-fashioned idea of a species [is that] it’s reproductively isolated from other species,” said Rasmus Nielsen, a geneticist at the University of California who wasn’t involved in the study. “This paper is a part of a series of papers that have been saying that worldview really is wrong.”

And since animal genomes are so massive, there’s plenty of room for variation in some genes. Just by chance alone, similar genes located in distantly related animals can appear similar, and identical genes in closely related animals can appear different.

“If we get an overabundance of genome positions where cave bears and brown bears are showing more similarity to each other than to polar bears, then something else must have happened,” Barlow said. “And that something is hybridization between the two species.”

The findings were published in Nature Ecology and Evolution.

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NWT_Animals NWT_Biology SCI TECH

Scientists solve mystery behind bird egg shape

A team of scientists just discovered why guillemot eggs have their strangle shape—a centuries-old mystery that has stumped biologists for hundreds of years.

A previous theory suggested that the egg’s pointed shape evolved to aid its arc-like rolling motion in order to prevent it from rolling off of a cliff while being incubated on a cliff ledge. Now, a new study reveals that the shape actually evolved to keep the egg in place and prevent it from rolling away at all.

“Guillemots are one of the most fascinating species of birds that we have in the UK, however they are often overshadowed by their neighbour, the puffin,” said Tim Birkhead of the University of Sheffield. “This is mostly because people love the way puffins look, but in terms of behaviour, guillemots are much more interesting for nature enthusiasts to watch.”

“Apart from looking cute, Puffins don’t really do much at the colony,” he added. “In contrast, watching guillemots is like watching nature’s very own soap opera: a never-ending mix of marital affection, infidelity and strife. And, in terms of keeping a health check on the oceans, you can’t beat guillemots since we can survey their numbers, survival and breeding success more easily accurately than almost any other seabird.”

The groundbreaking study dispels the old belief that the pointed eggs evolved to promote an arc-like rolling motion and highlights the fascinating nature of guillemot eggs, which are considered to be one of the most beautiful eggs in the world.

The findings were published in The Auk.