Friday, 28 April 2017

Scythian horse breeding unveiled: Lessons for animal domestication


Date: April 27, 2017
Source: Faculty of Science - University of Copenhagen

Nomad Scythian herders roamed vast areas spanning the Central Asian steppes during the Iron Age, approximately from the 9th to the 1st century BCE (Before Common Era). These livestock pastoralists, who lived on wagons covered by tents, left their mark in the history of warfare for their exceptional equestrian skills. They were among the first to master mounted riding and to make use of composite bows while riding. A new study published in Science led by Professor Ludovic Orlando and involving 33 international researchers from 16 universities, now reveals the suite of traits that Scythian breeders selected to engineer the type of horse that best fit their purpose.

The study took advantage of exceptionally preserved horse remains in royal Scythian burials, such as the site of Arzhan, Tuva Republic, where over 200 horses have been excavated but also at Berel', Kazakhstan, where no less than 13 horses were preserved in a single, permafrozen funerary chamber. Applying the latest methods in ancient DNA research, the researchers could sequence the genome of 13 Scythian stallions. These were 2,300-2,700 years old and included 11 specimens from Berel' and two from Arzhan. The researchers also sequenced the genome of one 4,100 year-old mare from Chelyabinsk, Russia, belonging to the earlier Sintashta culture, which developed the first two-wheeled chariots drawn by horses.

The DNA variation observed at key genes revealed a large diversity of coat coloration patterns within Scythian horses, including bay, black, chestnut, cream and spotted animals. Scythian horses did not carry the mutation responsible for alternate gaits, and as a consequence, were not natural amblers. However, some but not all individuals carried variants associated with short-distance sprint performance in present-day racing horses. This indicates that Scythian breeders valued animals showing diverse endurance and speed potential.

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Family tree of dogs reveals secret history of canines

By Helen Briggs BBC News

25 April 2017

The largest family tree of dogs ever assembled shows how canines evolved into more than 150 modern breeds.

Dogs were first selected and bred for their ability to perform tasks such as herding goats or cattle, say scientists.

Later, they were selected for physical features such as their size or colour.

The study also unearths evidence that some dogs are descended from an ancient breed that travelled with the ancestors of Native Americans into the Americas.

Archaeological evidence points to the so-called "New World dog", which apparently crossed with human settlers over a land bridge from Asia.

It had previously been thought that all signs of this ancient breed had been erased as dogs bred in Europe spread around the world.

"We think there is still some signature of New World dog hiding in the genome of some of these American breeds," said co-researcher Heidi Parker of the National Institutes of Health, US.

Modern hairless breeds such as the Peruvian hairless dog and the Mexican hairless dog are likely descended from this ancient dog.
 

Brown bears found to leave scent signals by twisting feet into the ground

April 28, 2017 by Bob Yirka

(Phys.org)—A team of researchers from Poland, Spain and Austria has discovered that brown bears living in Poland have glands in their paws that produce chemicals that the bears use to communicate with other bears. In their paper published in Scientific Reports, the team describes their study of multiple bears in the wild and what they observed.

As the researchers note, many animals both on land and in the sea use chemical signaling as a way to communicate with one another. Such chemicals when dispersed into the environment can be used by others of the same species to learn about the animal that left them by simply sniffing them.

Prior research has shown that brown bears are typically loners who establish large territories. Such a lifestyle would seem to suggest the need for long range communications—to let other bears know of territory borders, occupant age, gender, etc. Also, there would be a need for females to signal males when they are ready for mating. To learn more about possible chemical signaling in brown bears, the researchers began by examining skin samples from two bears—one in the wild and one from a zoo. They found that the bears had glands in their feet that secreted chemicals that could be released when the feet were twisted on the ground. Upon examining the secreted chemicals, the researchers found 20 compounds suitable for use in communicating information such as gender, readiness for mating, etc.

To better understand how the bears might use chemical signaling, the researchers watched and filmed wild bears living in the mountains of southern Poland from 2014 to 2016. They also filmed bears living in the mountains in Spain over the course of a three-year period.

In looking at the film the researchers report that they observed bears intentionally twisting their feet on the ground as they walked in certain instances—a move that would likely release the secreted chemicals to the ground. They also found that many of the bears would retrace steps they had taken before, carefully placing their feet into the prints they had left behind—perhaps updating their profile. In some cases, multiple twistings over time had led to bare patches of ground that presumably would serve as listening posts for other bears who happened upon them. They also report that males appeared to engage in feet twisting more than females.

Read more at:

Some Brisbane reptiles double in size because of which park they live in: study - Via Herp Digest

Sydney Morninng Herald, 4/27/17 by Amy Mitchell Whittington

Water dragons living in separate parks across Brisbane have evolved differently from one another in a process likened to the Galapagos Islands evolution recorded by Charles Darwin, a Queensland researcher says.

The first "clue" was a DNA variation across 570 eastern water dragons at South Bank, Roma Street Parkland, the City Botanic Gardens and Mt Coot-tha Botanic Gardens monitored by University of Sunshine Coast Senior Research Fellow Dr Celine Frere.

"That was the first clue to tell us there was something going on in the city that was not your conventional type of evolution," Dr Frere said.
Studies revealed there were also physical differences between each population that lived within kilometres of each other.

The study, published in the journal Molecular Ecology, found males varied in overall size, while females varied in terms of head and leg size, Dr Frere said.
"The animals at the city botanical gardens, they are by far the largest animals and they seem to have, in relation to body size, shorter limb length than other parts," she said.

"In contrast, the animals we found at Mount Coot-tha botanical garden are smaller in size but they have longer back limbs.

"At Roma Street Parkland the animals are quite small but they have larger heads and shorter limbs whereas the animals at South Bank are also fairly small but they have smaller heads and longer limbs.”

While Dr Frere did not know why this species had evolved so differently in a short time – over 32 generations in "lizard time" or since the city's development in the mid to late 1800s – she suggested landscape and microhabitat variations were likely factors.

"The simplest explanation is to think of each city park as being quite a unique ecosystem and different to one another," she said.

"Each of these city parks are different ecosystems, are geographically isolated ... we could look at city parks as islands in a jungle of concrete that make up this archipelago that has similar evolutionary processes like the Galapagos."
Dr Frere said the heaviest male caught during the study, from the City Botanic Gardens, weighed 1.4 kilograms, almost double that of males caught in native habitats.

"This is a common thread when you study island evolution: they say (gigantism) is a biological phenomenon where the size of an animal when isolated on an island increases dramatically compared to its mainland relative," she said.
Dr Frere said the staggered process by which the parks were developed – Mt Coot-tha opened in the 1970s while South Bank opened in the 1980s – could have also influenced the variation.

"Anthropogenic pressures, while they do extensive damage to biodiversity, they are recognised as one of the more significant selective pressures that results in rapid evolution," she said.

"We talk about this idea that cities may be representing these theatres for rapid evolution because animals that do live within cities have to drastically change their way of life.”

So what is the next step in this evolutionary expedition?

"We are going to study the ecology of these parks in much more detail, the thermal landscape and the 3D landscape ... looking also at the biodiversity composition in terms of diet and how these animals are negotiating these landscapes by GPS tracking them and looking at their fine-scale movements across a few days," she said.

"We often thought of this as an urban versus non-urban dichotomy … but here it is to show we go even deeper than that, it is every dragon within every city park (being) extremely different to other dragons in another city park."

Planet of the Turtles: Elite few brave deep waters to snag turtles for research - via Herp Digest


April 26, 2017  By Judah Breitbach, The Bucaaneer

Professor Brian Hauge’s “wootie woo” might be mistaken for a bird’s call, albeit a bird that’s slightly off- key, but rather, the distinctive call is meant to gather and silence students.

It seems to work as Hauge rallies students every year under the banner of the North American Freshwater Turtle Research Group, NAFTRG.

“We went to Weeki Wachee springs state park, Manatee springs, and other locations. The manatees just show up and get in the way,” says Hauge, “We’re really there for the turtles, but the students are crazy about the manatees.”

The Manatees aren’t the only thing that gets in the way. There’s a densely growing grass at the bottom of the lagoons and rivers that Hauge feels may be pressing the Musk Turtle for space, thusly forcing their population to move closer to the water’s surface for food.

“The vegetation is changing, so the species that interact with the vegetation are changing,” Hauge says of the shifting environment in the Springs, one of the most densely populated with freshwater turtles in the world.

A poster outside Hauge’s office evangelizes passersby on the importance of turtle population as an indicator of a regional ecosystem. The Auburn University graduate and the six Pirate student scientists, as well as two Western Washington University Huxley college students, noticed that the Musk Turtle in particular may be in decline.

“That’s something my students and I are going to try to get a handle on,” Hauge said. “We’re going to take data from all the way back from 2000 until now, and look at the number of captures over that given period of time to document that the numbers are lower. Because they are definitely lowering for the Musk Turtle.”

The pilgrimage to turtle mecca is an annual one for Hauge. He’s been taking students to Central Florida for the research project for many years. The site is one of many for the NAFTRG. Others include freshwater turtle habitat in Pennsylvania, Tennessee, and Texas.

Even Doctors have heroes. Hauge meet with long- time mentor and confessed role model when it comes to turtle research, John Iverson, professor of biology at Earlham University, Indiana. “This is a perfect op- portunity, a perfect location in which we can do turtle research,” Iverson mentioned to the ‘Orlando Sentinel.’

Thursday, 27 April 2017

Conservationists call for moratorium on logging to save endangered Leadbeater’s possum

Victorian government asked to ‘completely prohibit logging’ on more than 100,000 hectares of the state’s mountain ash forest

Calla Wahlquist
 

Monday 24 April 2017 23.16 BST Last modified on Tuesday 25 April 2017 00.40 BST

Conservationists have called for a moratorium on logging more than 100,000 hectares of Victoria’s remaining native forest estate to protect the critically endangered Leadbeater’s possum.

Environmental Justice Australia, acting on behalf of volunteer organisation Friends of the Leadbeater’s Possum, wrote to the Victorian environment minister, Lily D’Ambrosio, on Monday requesting she implement an interim conservation order to “completely prohibit logging within the critical habitat of the Leadbeater’s possum” in order to ensure the survival of the species, which is at risk of dying out within the next 40 years.

The critical habitat area is made up of 171,345 hectares of mountain ash forest in central Victoria, according to recent research.

According to lawyer Danya Jacobs, about 101,400 hectares of that habitat is currently available for logging.

The proposal would see state-owned logging corporation VicForests lose access to almost a quarter of its remaining 490,000-hectare native production forests, leaving it unable to meet already reduced logging quotas.

The majority of Victoria’s native forest logging reserves are in the mountain ash forests of central Victoria and Gippsland, an area that overlaps with Leadbeater’s possum habitat.

In a letter provided to Guardian Australia, Jacobs argues that existing protections in place for the species are “inadequate and not working” and that the possum was at “very high risk of extinction if additional areas of its habitat are not protected”.



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Japan to exceed bluefin tuna quota amid warnings of commercial extinction

Conservationists call on Japan to abide by fishing agreements after reports annual quota will be exceeded two months early

Justin McCurry in Tokyo

Monday 24 April 2017 13.19 BST First published on Monday 24 April 2017 12.21 BST

Conservation groups have called on Japan to abide by international agreements to curb catches of Pacific bluefin tuna after reports said the country was poised to exceed an annual quota two months early – adding to pressure on stocks that have already reached dangerously low levels.

Japan, by far the world’s biggest consumer of Pacific bluefin, has caused “great frustration” with its failure to abide by catch quotas intended to save the species from commercial extinction, said Amanda Nickson, the director of global tuna conservation at Pew Charitable Trusts.

“Just a few years of overfishing will leave Pacific bluefin tuna vulnerable to devastating population reductions,” Nickson said in Tokyo on Monday. “That will threaten not just the fish but also the fishermen who depend on them.”

Decades of overfishing have left the Pacific bluefin population at just 2.6% of its historical high, and campaigners say Japan must take the lead at a summit in South Korea this summer.

In 2015, Japan and other members of the Western & Central Pacific Fisheries Commission agreed to curtail catches of immature bluefin, halving the catch of fish under 30kg from the average caught between 2002 and 2004.



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Paleontologists identify new 507-million-year-old sea creature with can opener-like pincers


Discovery points to origin of millipedes, crabs and insects among other species

Date: April 26, 2017
Source: University of Toronto

Paleontologists at the University of Toronto (U of T) and the Royal Ontario Museum (ROM) have uncovered a new fossil species that sheds light on the origin of mandibulates, the most abundant and diverse group of organisms on Earth, to which belong familiar animals such as flies, ants, crayfish and centipedes. The finding was announced in a study published today in Nature.

Limited gene flow between two Bengal tiger populations in the western Himalayan foothills


Connectivity could be maintained by relocating villages, and banning sand and boulder mines 

Date: April 26, 2017
Source: PLOS
 
The flow of genes between Bengal tigers in two reserves of the Terai Arc Landscape in western Himalayan foothills is too low, according to a study published April 26, 2017 in the open-access journal PLOS ONE by Surendra Prakash Goyal from Wildlife Institute of India, India, and colleagues.

Tigers are endangered partly due to habitat loss, which can fragment populations and reduce gene flow among them. Gene flow between populations can maintain genetic variation and spread beneficial gene alleles, so understanding the gene flow of isolated tiger populations i.e. in western Himalayan foothills is crucial in developing management strategies for conserving these big cats. Goyal and colleagues analyzed DNA from 71 samples of tissue, blood or scat from Bengal tigers to assess their gene flow in an 1,800-square-kilometer region of the western Himalayan foothills. The region has two main subpopulations of tigers, one in the Rajaji Tiger Reserve and the other in the Corbett Tiger Reserve.
 

Wednesday, 26 April 2017

This caterpillar could be the key to biodegradable plastic


April 25, 2017

by Chuck Bednar

A species of caterpillar that typically consumes honey and the wax from beehives may be the answer to the growing problem of plastic waste, as new research has revealed that it can easily devour a commonly used type of the material and cause it to return to a useful compound.

As Spanish National Research Council (CSIC) scientist Federica Bertocchini and her colleagues reported Monday in the journal Current Biology, the larvae of the greater wax moth (or Galleria mellonella) is capable of causing polyethylene, a type of plastic used in shopping bags and food packaging, to biodegrade into a substance that can be used in various consumer products. Bertocchini discovered that the caterpillars, which are also known as wax worms, had a taste for plastic while removing them from beehives, Sky News and the Los Angeles Times explained. As she extracted them, she placed them in plastic bags, and later found those bags full of holes.

Following that discovery, she and her colleagues observed wax worms placed on a polyethylene film and found that in as little as 40 minutes, the insects had already started boring holes through the plastic material. In fact, each worm was consuming it at a rate of roughly 2.2 holes/hour, and a team of 100 caterpillars consumed 92 milligrams of a plastic shopping bag in 12 hours.

To further test the wax moth larvae, they created a slurry of worms and placed it on polyethylene films, the Times said. Fourteen hours later, 13 percent of the plastic’s mass had degraded, and the research team discovered that the worms had left behind ethylene glycol – a compound used as a coolant, a heat transfer agent, and in the manufacturing of polyester fibers and plastic bottles.

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Baby whales 'whisper' to mothers to avoid predators: study


April 26, 2017 by Valerie Dekimpe

Newborn humpback whales and their mothers whisper to each other to escape potential predators, scientists reported Wednesday, revealing the existence of a previously unknown survival technique.

"They don't want any unwanted listeners," researcher Simone Videsen, lead author of a study published in Functional Ecology, told AFP.

"Potential predators such as killer whales could listen to their conversations and use that as a cue to locate the calf and predate on it."

Whales are known for their loud calls, congregating fellow members of the pod. Male humpback whales also emit reverberating sounds to attract females during the mating season.

But this is the first time scientists have observed a unique, intimate form of communication between humpback mothers and calves.

Researchers from Denmark and Australia tracked each of eight calves and two mothers for 24 hours in Exmouth Gulf, Western Australia, a breeding ground for Antarctic humpback whales seeking warmer waters to mate and give birth.

Using tags attached to the animals, the team of scientists recorded their faint squeaks and grunts.

"These signals between mother and calf are more quiet than those of normal adult humpback whales," Videsen said, noting they were 40 dB lower than the singing of males in the area.

While a male's cry can resound over an area covering several kilometres, the pairs in the study could only hear each others' calls within a distance of less than 100 metres (330 feet), she added.

Read more at: 

Researchers identify genes that help trout find their way home

April 26, 2017 by Robin A. Smith
 
Scientists have identified genes that enable rainbow trout to use Earth’s magnetic field to find their way back to the streams where they were born. Credit: Eric Engbretson, U.S. Fish and Wildlife Service

In the spring when water temperatures start to rise, rainbow trout that have spent several years at sea traveling hundreds of miles from home manage, without maps or GPS, to find their way back to the rivers and streams where they were born for spawning.

In a study published April 26, 2017 in Biology Letters, researchers have identified genes that enable the fish to perform this extraordinary homing feat with help from Earth's magnetic field.

Generated by the flow of molten metal in its core, the Earth's magnetic field ranges from a mere 25 microteslas near the equator to 65 microteslas toward the poles—making it more than a hundred times weaker than a refrigerator magnet.

Diverse animal species can detect such weak magnetic fields and use them to navigate. First identified in birds in the 1960s, this sense, called magnetoreception, has since been documented in animals ranging from bees and salamanders to sea turtles.

But despite more than half a century of research, the underlying molecular and cellular machinery remains a mystery.

To work out the genetic basis, Duke University postdoctoral associate Bob Fitak and biology professor Sönke Johnsen and colleagues investigated changes in gene expression that take place across the rainbow trout genome when the animal's magnetic sense is disrupted.

In a basement aquarium on the Duke campus, they randomly scooped up one fish at a time from a tank into a small holding container, and placed the container inside a coil of wire. The coil was connected to a capacitor, which discharged an electric current to create a split-second magnetic pulse inside the coil, about 10 times weaker than the magnetic field generated by an MRI machine in a hospital.

Next the researchers sequenced all the gene readouts, or RNA transcripts, present in the brains of 10 treated fish and 10 controls to find out which genes were switched on and off in response to the magnetic pulse.

Read more at: 

When Hunting Pythons, It Helps to Dance Like a Monkey—and Carry a Sledgehammer - via Herp Digest


Florida’s Everglades are crawling with nonnative giant snakes, and authorities have hired an elite corps of hunters to track them down; ‘you juke left, you juke right’

By Arian Campo-Flores, Wall Street Journal, April 21, 2017 

THE EVERGLADES, Fla.—For people who prefer to avoid large, scary snakes, Tom Rahill’s routine won’t be of much use.
 
Anyone desiring to get acquainted with a python deep in the wild, though, would do well to learn his “scalded-monkey dance.”
 
That’s the shimmy Mr. Rahill does when he hunts down a fat Burmese python in the Everglades—a bob-and-weave boogie he uses to avoid the snake’s strikes until he can subdue and grab it.
 
“The attractive thing about this,” he said of snake-hunting, “is it’s very primal.”

There are multiple ways to catch a python, and Mr. Rahill employs a good number of them as a member of an elite squad of hunters the South Florida Water Management District pays to track down these interlopers, which biologists estimate to number in the tens of thousands.

The nonnative serpents have spread through the Everglades, gobbling birds and mammals. They grow as thick as telephone poles and as long as 20 feet. They aren’t venomous, killing by coiling around an animal and suffocating it before gulping. There have been reports abroad of pythons swallowing humans.

“I’m feeling good about this,” said Mr. Rahill one morning last month, trudging through dense brush while swatting mosquitoes and avoiding poisonwoods that can trigger rashes.
Mr. Rahill is the 59-year-old founder of Swamp Apes, a group that takes military veterans into the wilderness for various activities including snake hunting. He said it has bagged more than 400 pythons.

“This is perfect python habitat,” he said, approaching an elevated hardwood hammock. He looked for telltale signs—matted grass, shed skin—jabbing his walking stick into crevices.
He sniffed the air for python poop. “Acrid,” he explained, “more biting than gator” variety.

Mr. Rahill, a telecom administrator, is among 25 hunters the agency selected from more than 1,000 applicants to hunt down the beasts. The elite few include three Swamp Apes members and Dusty “The Wildman” Crum, 36, an orchid grower whose hunting team in a 2016 contest nabbed a 15-foot python.
 
The agency pays $8.10 an hour, $50 per python—must be delivered dead—and $25 for each foot over four.

The program is the latest in a string of attempts by state and federal agencies to eradicate the beasts, from deploying dogs trained to pick up their scent to releasing “Judas snakes” outfitted with radio transmitters to lure other pythons.

In January, the Florida Fish and Wildlife Conservation Commission and other parties hired two members of the snake-hunting Irula tribe in India, who the agency says captured 33 pythons over a two-month period.

They began each day with a sort of prayer and “would ask the powers that be for the vision to see these snakes,” said Joe Wasilewski, 64, a conservation biologist who helped arrange the effort.
 
Then they would light up thin Indian “bidi” cigarettes and head out, searching for faint signs of the serpents. “They’re so darn good at it,” Mr. Wasilewski said. “They’re like exterminators.”

None of the initiatives has done much to curb the Everglades-python population. Though the snakes can reach monstrous proportions, their camouflage and tendency to hide in holes and under leaves make them difficult to spot. “You can stand right on top of it in vegetation,” said Bryan Falk, 38, a U.S. Geological Survey research ecologist, “and you wouldn’t know it.”

Pythons, native to Asia, probably entered the Everglades decades ago when they escaped from, or were released by, people who bought them as pets, scientists say. They eat marsh rabbits and wading birds, robbing native predators such as panthers and alligators.

Bobby Hill, 65, whose job is to remove exotic species from land overseen by the water-management district, said he has found deer hoofs, alligator scales and a bobcat claw in pythons’ bellies. Years ago, along local highways, “you’d see road kill—raccoons, possums,” he said. “You don’t see that too much anymore.”
Hunters say the best time to find pythons is after a cold night when the sun begins to bake the ground where the reptiles head to bask. Most of the year, the steam-bath environment sends them searching for cover.

If a hunter locates one, the challenge is catching it. In dense foliage, Mr. Rahill yanks on the body to pull it toward a clearer spot where it can’t coil around anything. Then he tries to subdue it by the neck.

There are dangers at either end: strikes from its head and defensive sprays from its tail of musk and excrement. “They’ll fling white blobs of poop everywhere,” Mr. Rahill said.
Which is where the scalded-monkey dance comes handy. “You juke left, you juke right” to avoid strikes, he said, until the reptile is tired out and provides an opening to pounce.

Another Swamp Ape, he said, does more of a ballet movement. “He’s a joy to watch, so smooth and fluid.”

Mr. Hill prefers a simpler snake-subjugation tactic: He grabs his Winchester 12-gauge shotgun and fires at the python’s head. “A head shot is considered a humane way” to kill a snake, said Mr. Hill, who said he has been involved in capturing more than 700 pythons.

On the recent day in the Everglades, Mr. Rahill found no snake in the brush, so he tried a method he calls “road cruising.” He hugged the roadside in his black Chevy Cavalier—295,000 miles on the odometer, missing a hubcap—searching through the open window for that python-skin glisten.
He ended the day empty-handed, saying “the key to successful pythoning is perseverance.”

Novice hunters often don’t realize how difficult it is to pursue pythons, he said. “Some people think pythons are waiting on levees with signs saying, ‘Welcome to Florida.’ ”
Days later, farther north, he was tramping through brush and glimpsed a python pattern on a mound, he said. He lunged at it, grabbed at the snake midbody and pulled it into the open. The snake tried to strike him several times before he subdued and bagged it.

The 7-footer yielded a $125 bonus. “I earned that snake,” he said.
The snake earned a swift end dealt by Mr. Rahill’s sledgehammer.

Monday, 24 April 2017

Tarantulas use their lateral eyes to calculate distance

Date: April 20, 2017
Source: FECYT - Spanish Foundation for Science and Technology
 
The tarantula species Lycosa tarantula ambushes its prey and lives in burrows around 20 cm deep topped by a structure, a kind of turret which the tarantula build from twigs, leaves and small stones, fastened with the spider's silk. From the turret, the tarantula surprises its prey and runs to pursue it, subsequently returning to the burrow from distances between 30 and 40 cm.

L. tarantula uses path integration to return to its burrow. With this mechanism, it does not follow the same path back to its burrow; instead, it moves as though it had followed the sides of a right-angle triangle, returning along the hypotenuse.

In 1999, a research team from the Autonomous University of Madrid discovered that these animals used polarised light from the sky to know their position with respect to their nest. In the new research, the scientists wanted to go beyond this, and have analysed the role of each pair of the tarantula's eyes (they have four pairs in total) in the process of distance measurement, or odometry.

"To calculate the distance it has travelled, the animal needs an odometer that registers the route, its location with respect to the finish point, which would be the burrow, and a 'compass' to track the direction of travel," according to Joaquin Ortega Escobar, lead author of a paper published in the Journal of Experimental Biology on the function of each eye in these processes.

The 'compass' would correspond to polarised light, which the median eyes use to measure the angle; direction is detected by the anterior lateral eyes. Through this research, the scientists have learned that it is principally the anterior lateral eyes (which until now had not been analysed), and to a lesser extent the posterior lateral eyes, that help tarantulas measures the distance to their nest.

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Recovering species must be celebrated or we risk reversing progress


Date: April 20, 2017

Source: University of Cambridge
 

A failure to celebrate conservation successes means we miss vital opportunities to convince the public of "real and practical solutions" they can engage with, says a leading conservationist.

Writing in the journal Oryx, Andrew Balmford, Professor of Conservation Science at the University of Cambridge, argues that any progress risks being reversed if we "let drift the many gains that the conservation movement is making."

Progress redefines what we consider normal, he says, as in the case of the smoking ban or rights for women. Such "positive shifting baselines" even extend to the green shoots of nature's recovery through conservation -- from birdlife in the UK's Avalon marshes to monkeys in Brazilian forests.

However, Balmford says conservation improvements can quickly get taken for granted. When combined with the seemingly endless torrent of bad news about nature, he believes the overall effect can render people hopeless.

"If we forget where we've come from, we risk allowing things to slip backwards," he writes, pointing to examples in the UK and US where early species recoveries have already led to official sanctioning of hunting and culling of partially restored populations.

In an effort to shift the balance towards celebrating and reinforcing success, Balmford and colleagues from the Cambridge Conservation Initiative are organising Cambridge University's contribution to a day of global action. #EarthOptimism will promote a much more positive outlook on the future of the natural world.



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Genetic evidence points to nocturnal early mammals

Date: April 20, 2017
Source: Stanford University


Our earliest mammalian ancestors likely skulked through the dark, using their powerful night-time vision to find food and avoid reptilian predators that hunted by day. This conclusion, published by Stanford researchers April 21 in Scientific Reports, used genetic data to support existing fossil evidence suggesting that our distant relatives may have adapted to life in the dark.

The team, led by Liz Hadly, professor of biology and senior author on the paper, examined genes involved in night vision in animals throughout the evolutionary tree, looking for places where those genes became enhanced.

"This method is like using the genome as a fossil record, and with it we've shown when genes involved in night vision appear," Hadly said. "It's a very powerful way of corroborating a story that has been, up to now, only hypothesized."



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Sea Urchins Launch Their Weird Mobile Jaws to Scare Predators

By Stephanie Pappas, Live Science Contributor | April 24, 2017 07:08am ET

A common and colorful sea urchin has some truly bizarre appendages that seem to move independently from its body, and now scientists know why: It shoots these tiny, venomous jaws into the water to deter predators.

These teensy, toothy jaws are called pedicellariae, and when scientists discovered them in the early 1800s, they thought the jaws were parasites because they seemed to move independently from the urchin. Now, researchers find that urchins use their pedicellariae not only to defend themselves when attacked, but also as a warning to fish and other sea creatures to "stay away!"

Tripneustes gratilla, otherwise known as the collector urchin, is a widespread species found in shallow waters in the Bahamas, the Indo-Pacific region and even the Red Sea.



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