How did primate brains get so big?

Top and bottom views, respectively, of the virtual brains of Notharctus tenebrosus (A, B, C, E and F), Adapis parisiensis (G and H) and Smilodectes gracilis (bottom two rows) within transparent renderings of their skulls.

Virtual brains reconstructed from ancient, kiwi-sized primate skulls could help resolve one of the most intriguing evolutionary mysteries: how modern primates developed large brains.

University of Florida paleontologists found clues in the remarkably preserved skulls of adapiforms, lemur-like primates that scurried around the tropical forests of Wyoming about 50 million years ago. Thought to be a link between primitive and advanced primates, their fossil skulls were the best evidence available for understanding the neuroanatomy of the earliest ancestors of modern primates. But there was just one problem -- the brain cavities of the fragile skulls contained only rock and dust.

That is, until Arianna Harrington, then a UF undergraduate student and later a master's student at the Florida Museum of Natural History on the UF campus, used CT technology to create the first virtual 3-D brain casts of the early primates. The eight virtually reconstructed and dissected brains -- the most ever created for a single study -- show an evolutionary burst including improved vision and more complex neurological function preceded an increase in brain size, said Harrington, now a Duke University doctoral student. Details of the findings are described online in the Journal of Human Evolution.

"It may be that these early specializations allowed primate brains to expand later in time," said Harrington, the study's lead author. "The idea is that any patterns we find in primate brain evolution could lead to a better understanding of the early evolution that led to the human brain."

Scientists have long debated whether primates have always had big brains compared to body size, or if this was a trait that appeared later. The new study's findings are consistent with previous endocast studies of Australopithecus afarensis, the oldest hominid known, and Victoriapithecus macinnesi, an early Old World monkey, which showed brain size increase followed brain specialization in early hominids and monkeys.

Adapiforms, which are not directly related to humans, evolved after the earliest primate ancestors, called plesiadapiforms, which lived about 65 million years ago. Harrington and colleagues created virtual endocasts for three different species of adapiforms: Notharctus tenebrosus and Smilodectes gracilis from the middle Eocene Bridger formation of Wyoming and a late Eocene European specimen named Adapis parisiensis.

Adapiforms' skulls differ from the earlier plesiadapiforms in a few ways including having more forward-facing eyes. Thanks to the new virtual endocasts, scientists were able to take a closer look at anatomical features which revealed that, while adapiforms placed relatively less emphasis on smell more similar to modern primate brains, the relative brain size was not so different from that of plesiadapiforms, said study co-author Jonathan Bloch, curator of vertebrate paleontology at the Florida Museum.

"While it's true humans and other modern primates have very large brains, that story started down at the base of our group," Bloch said. "As our study shows, the earliest primates actually had relatively small brains. So they didn't start out with large brains and maintain them."

Read more at Science Daily

New, Nearby Earth-Like Planet Discovered

The Hubble Space Telescope captured this image of our nearest star, Proxima Centauri.

Scientists are preparing to unveil a new planet in our galactic neighborhood which is "believed to be Earth-like" and orbits its star at a distance that could favor life, German weekly Der Spiegel reported Friday.

The exoplanet orbits a well-investigated star called Proxima Centauri, part of the Alpha Centauri star system, the magazine said, quoting anonymous sources.

"The still nameless planet is believed to be Earth-like and orbits at a distance to Proxima Centauri that could allow it to have liquid water on its surface -- an important requirement for the emergence of life," said the magazine.

"Never before have scientists discovered a second Earth that is so close by," it said, adding that the European Southern Observatory (ESO) will announce the finding at the end of August.

The report gave no further details.

Contacted by AFP, ESO spokesman Richard Hook said he is aware of the report, but refused to confirm or deny it. "We are not making any comment," he said.

NASA has announced the discovery of new planets in the past, but most of those worlds were either too hot or too cold to host water in liquid form, or were made of gas, like our Jupiter and Neptune, rather than of rock, like Earth or Mars.

Last year, the U.S. space agency unveiled an exoplanet that it described as Earth's "closest-twin."

Named Kepler 452b, the planet is about 60 percent larger than Earth and could have active volcanoes, oceans, sunshine like ours, twice as much gravity and a year that lasts 385 days.

But at a distance of 1,400 light-years away, humankind has little hope of reaching this Earth-twin any time soon.

In comparison, the exoplanet orbiting Proxima Centauri, if confirmed, is just 4.24 light-years away.

This is a mere stepping stone in relation to the scale of the universe but still too far away for humans to reach in present-generation chemical rockets.

Read more at Discovery News

'Flamboyant' New Sea Slug Needs a Name

A "photogenic and flamboyant" new species of sea slug has been found in waters off North Western Australia, according to the Western Australian Museum.

The discovery shows that even very distinctive animals can go undiscovered over long periods, particularly if they live in more remote or less-traveled locations.

In this case, Nerida Wilson, a senior research scientist at the museum, first noticed the nudibranch while diving. That was 16 years ago. It's taken this long to scientifically confirm that the colorful creature is a new species.

Now the race is on to name the new marine species, and the public is asked to help.

The museum, along with Radio Nation's "Off Track" program, is holding a contest to determine the second part of the slug's name. The genus for the new nudibranch species is Moridilla, so they are looking for Moridilla x, with you filling in the "x." (Scientists use the letters "sp" in place of the "x" when referring to a species that hasn't been fully named yet.)

Below are some examples of what common complete scientific names look like:

Humans = Homo sapiens; Domestic cats = Felis catus

Some pretty awful entries have come in so far. One media outlet suggested something like Moridilla mcslug. You can do better! The competition closes at the end of Sunday, Aug. 14, U.S. ET time (23:59 Australia time on Monday, Aug. 15).

In addition to the honor of naming the nudibranch, the winner will also receive two flights to Perth, Australia, hotel and transportation -- plus a private tour of the museum to see the specimen.

"Off Track" and the museum recently released the first ever video of the animal:

They have also shared a list of factoids to consider when coming up with the name. They include:

•     If threatened, the nudibranch has an amazing flashing display, which involves whipping its cerata (orange-tipped appendages) in and out. This creates a colorful and "scary" warning to predators that eating this thing might be dangerous.
•     The cerata will regenerate over time if they're lost in an accident.
•     It is a hermaphrodite and its sex organs are near what we might think of as its neck.
•     It can grow to about 4 inches long.
•     This species appears to be very active, and does not spend as much time hiding in crevices as other nudibranchs do.
•     It moves via a snail-like foot that is cream-colored.
•     Its oral tentacles are orange and tap in front of the sea slug as it moves, sensing the way by touch.
•     It has chemically sensitive organs known as rhinophores that stand up alert like feathery rabbit ears.
•     The nudibranch breathes through its skin.

Read more at Discovery News

Study Draws New Map of Human Passage into Americas

The first people to reach the Americas could not have passed through the ice sheet-cleaving inland corridor long thought to be the entry point of humans to the continents, according to a study published Wednesday.

More likely, the New World pioneers of our species -- probably some 15,000 years ago -- inched along a Pacific coastline free enough of ice to support life-sustaining flora and fauna.

The exact route and timing of this maiden migration remains conjecture, the researchers said.

But what is certain, according to findings reported in the journal Nature, is that the textbook version of that passage is wrong.

For decades, scientists favoured a scenario something like this.

About 14,500 years ago, a 1,500-kilometre (900-mile) north-south corridor opened up between the Cordilleran ice sheet -- which covered roughly what is today the Canadian province of British Colombia -- and the much larger Laurentide ice sheet, which smothered the rest of Canada.

The Ice Age was slowly giving way, but still held the region in its grip and -- draining the oceans by dozens of metres -- forged a land-bridge between Eurasia and Alaska.

So far, so good.

About a thousand years later, according to this theory, the first Ice Age humans moved through this elongated inland gateway to found new cultures to the south.

Among them was the Clovis people, who first show up in the archaeological record more than 13,000 years ago.

This storyline presumes, of course, that these path-breaking early people found sustenance along the way.

And that's where the theory falls apart, according to Mikkel Pedersen, a researcher at the Centre for GeoGenetics at the University of Copenhagen, and lead author of the study.

"The earliest point at which the corridor opens for human migration is 12,600 years ago," he told AFP.

While the passage may have been free, "there was absolutely nothing before this date in the surrounding environment -- not plants, not animals."

Nothing, in other words, that would have allowed humans to feed themselves during a long, hard slog between towering cliffs of ice.

Other research showing that humans might have arrived in the Americas at least 14,500 years ago -- and perhaps a couple of thousand years before that -- had already begun to undermine the ice sheet corridor hypothesis, forcing experts to look more closely at the possibility of a coastal route.

Pedersen and colleagues now appear to have closed the door on the inland route for good.

The innovative methods they used for reconstructing the late Ice Age ecosystem were crucial.

Rather than hunt for DNA traces of specific plants or animals buried in sediment -- the standard approach -- Pedersen's team used what is called a "shotgun" method, cataloguing every life form in a given sample.

"Traditionally, we have been looking for specific genes from a single or several species," he explained.

"But the shotgun approach really gave us a fantastic insight into all the different trophic" -- or food-chain -- "layers, from bacteria and fungi to higher plants and mammals."

The researchers chose to extract sediment cores from what would have been a bottleneck in the inland corridor, an area partly covered today by Charlie Lake in British Columbia.

The team did radiocarbon dating, and gathered samples while standing on the frozen lake's surface in winter.

Read more at Discovery News

Our ancestors: More gorilla than chimp

The StW352 partial right calcaneus (top) and images of a rendering (bottom) generated from high resolution CT scans.

A new study that for the first time examined the internal anatomy of a fossil human relative's heel bone, or calcaneus, shows greater similarities with gorillas than chimpanzees.

The study, titled: Trabecular architecture in the StW 352 fossil hominin calcaneus and published in the Journal of Human Evolution, was undertaken by a team of international researchers from the University of the Witwatersrand in South Africa, Duke University, University of Southern California and Indiana University in the US.

The team examined the internal anatomy of our human relative, the StW 352 Australopithecus africanus fossil, from South Africa's rich fossil record in the Cradle of Humankind World Heritage Site, some 40km from Johannesburg.

They analyzed the structure and orientation of trabecular struts -- the spongy material inside a bone -- in the fossil from Sterkfontein Member 4, demonstrating greater similarities between it and the heel bone of gorillas rather than humans or chimpanzees.

In doing this, the team revealed new insights into how our ancestors moved through and interacted with their environment approximately 2-2.5 million years ago. Similarities between the fossil from Sterkfontein and gorillas indicate that Australopithecus africanus, the species of human ancestor (or hominin) also represented by the Taung Child, or at least this individual member of the species, exhibited gorilla-like levels of joint mobility and structural reinforcement.

Results of the new study were surprising because other recent studies of the australopithecine calcaneus, focusing on its external anatomy, have emphasised similarities with chimpanzees or humans.

However, since the organisation of trabecular bone is determined in part by how an animal interacts with its environment during its lifetime, the gorilla-like features observed in the present study are particularly compelling in revising how we view behavioural reconstructions of our australopithecine ancestors.

Lowland gorillas are generally regarded as less arboreal than chimpanzees -- they spend less time in trees and generally less time climbing -- although it is important to remember that even gorillas depend on arboreal resources for their survival. Thus, the gorilla-like features in the Australopithecus africanus calcaneus substantiate claims that our hominin ancestors depended on arboreal resources for their survival, but importantly, it provides evidence that gorilla-like foot function should be considered more frequently when discussing the evolution of human feet and how they functioned within the environment.

Read more at Science Daily

Greenland Shark Lives at Least 272 Years

This Greenland shark has just been tagged and is swimming toward Uummannaq Fjord in northwestern Greenland.

There is a shakeup in the list of the world's longest-lived animals, as researchers have just determined that Greenland sharks live to be at least 272 years old, making them the vertebrates -- animals with a backbone or spinal column -- with the longest-known life expectancy.

Like an Olympic race for longevity, the Greenland sharks now exceed other incredibly long-lived animals, such as bowhead whales and tortoises. The findings, reported in the journal Science, indicate that the large, carnivorous sharks could even live much longer than 272 years.

Julius Nielsen, a doctoral student at the University of Copenhagen and the Greenland Institute of Natural Resources, told Discovery News: "We report the oldest shark to be at least 272 years (old). In more technical terms, it is with 95% certainty between 272 and 512 years old."

He added that the shark most likely died at around 390 years old, but due to the noted age range, he and his team stuck with the lower and more conservative figure for the paper.

It has long been suspected that Greenland sharks live ultra-long lives, but figuring out just how long has stumped marine biologists for decades. Usually the age of sharks and rays can be determined by counting seasonally deposited growth layers in hard calcified structures, such as fin spines. Greenland sharks, however, lack these hard structures.

To get around the problem, Nielsen and his team analyzed the eye lens nucleus of 28 female sharks sampled as accidental by-catch during the Greenland Institute of Natural Resources' annual fish and shrimp surveys. The research project is nicknamed Old and Cold, referring to the sharks' chilly environment and advanced ages.

Co-author Christopher Bronk Ramsey, a professor of archaeological science at the University of Oxford, told Discovery News, "The eye lens in all large animals forms during the initial development of the animal, and so dating this gives the age of the animal. Other body parts typically grow, or at least the carbon overturns over time. This is not possible for the lens because it has no internal blood supply."

The scientists measured the radiocarbon content of the Greenland shark eye lenses. Then, they estimated the age of the individuals by matching and calibrating the data using data representing radiocarbon changes in the northern North Atlantic marine food web the past 500 years.

The study marks the first time that scientists have applied a radiocarbon approach on eye lenses to date the longevity of a fish, which sharks are. Ramsey indicated that even he is in awe of the fact that the Bayesian statistics behind some of his and his colleagues' work were formulated in the 18th century, when the oldest of the sharks in the study were alive.

"This perhaps puts quite nicely into perspective how long the lives of these animals are, and conversely, how much humans have achieved within the lifetime of one of these sharks," he said.

A Greenland shark in the icy waters of Disko Bay, western Greenland.

The researchers estimate that the long-lived Greenland sharks do not reach sexual maturity until around 156 years of age. Ramsey suspects that, since females have to attain a certain size to keep the developing shark embryos within their bodies, they cannot begin to mate until they reach that size. Their growth rate is incredibly slow.

As for why this rate is so slow, and why the sharks live such long lives, Ramsey said these characteristics are probably due to "low metabolic rate, cold temperatures and limits to food supply. The shark is a very slow moving, cold-blooded species."

Researchers like Michael Keane of the University of Liverpool are studying long-lived animals to determine if they possess special genes or other features that help to safeguard them against age-related diseases, particularly cancer. Such research is still in its relative infancy, so more revelations about nature's own 'fountain of youth' are yet to come.

Ramsey said at least one commonality seems to apply to all of the long-living species: a very low metabolic rate.

Read more at Discovery News

Perseid Meteor 'Outburst' Could Be Awesome

All predictions suggest there's going to be a spectacular meteor shower, so get outside and look up!

It's that time of the year when dust from Comet Swift-Tuttle rains down on our atmosphere, producing the famous Perseid Meteor Shower.

The shower, which peaks around Aug. 12 every year, rarely disappoints and is known to generate its fair share of bright meteors, colloquially known as "shooting stars." The Perseids are a favorite among amateur astronomers, particularly in the Northern Hemisphere as the warmer nights and (if you're lucky) clear summer skies allow comfortable and extended viewing sessions.

Also, as with every meteor shower, no specialist equipment is needed. You just need a comfortable spot, warm clothes (yes, even in the summer, as sitting and lying still for long periods can sap body heat) and patience.

But this year holds some extra excitement -- there's going to be an outburst... probably.

As a comet orbits the sun, it deposits ice and dust particles as a trail through interplanetary space called a meteor stream. You can imagine these streams as the contrail produced by aircraft; meteor streams trace out the paths the comets have taken during their various orbital circuits. Every year at around this time, the Earth passes into Comet Swift-Tuttle's dusty trail.

Over the tens to hundreds to thousands of years after being deposited in space, these meteor streams are influenced by the gravities of the planets (particularly Jupiter) and it just so happens that this year, three different meteor streams are coinciding as Earth orbits through them.

"This year Jupiter's influence has moved the 1079, 1479, and 1862 streams closer to Earth, so all forecasters are projecting a Perseid outburst with double double normal rates on the night of August 11-12," Bill Cooke, Head of NASA's Meteoroid Environment Office, told EarthSky.org.

So what does this mean for us? It could mean that we see up to 200 meteors per hour. But these are meteors and just because there's a statistically higher chance of seeing more meteors than usual, it's by no means a sure bet. Still, the models strongly suggest there will be an outburst, so don't miss it -- get outside and watch for those streaks of light.

Though the peak is likely to be observed from the night of Aug. 11 to the pre-dawn morning of Aug. 12, it's worth taking a look tonight (Aug. 10) as activity will be picking up. Just go outside, look for the Perseid "radiant" (the location in the sky the meteors appear to originate), which is the constellation of Perseus and get comfortable.

Want to find out more about the Perseids and chat with astronomy amateurs and professionals? Be sure to follow #MeteorWatch on Twitter and across other social media platforms to join in!

"The Perseid Meteor Shower will be at its most active over the next few days and I will be doing my yearly #MeteorWatch for it," Adrian West (@VirtualAstro), astronomer and organizer of the MeteorWatch.org website, told Discovery News. "I'm trying my best to make astronomy more popular and accessible and the Perseids are always a winner."

Read more at Discovery News

Did Meteorite Impacts Sterilize Subsurface Mars Life?

The sites of meteorite impacts on Mars are often considered to be good places to look for life. After all, it's most likely that if any trace of life (past or present) ever took hold on the Red Planet, it would most likely be preserved under the bedrock of Mars' harsh surface. Should there be a recent impact, could we search the debris to seek-out this recently excavated pristine rock for life?

Alas, in new research, this kind of impact crater search could be a fool's errand; the energy of the impact likely sterilized any material we'd consider organic and related to life.

Researchers from Imperial College London carried out simulations of meteorite impacts in the lab to see how organic compounds fared when exposed to the kinds of impact pressures they could experience on Mars.

What they found wasn't very promising if we hope to find evidence of life inside impact craters. For example, organic compounds associated with basic microbial and algal life (known as long chain hydrocarbon-dominated matter) were destroyed by the pressure of impact. On the other hand, other organic compounds associated with plant life (known as aromatic hydrocarbons) were chemically altered, but, according to a press release, "remained relatively resistant to impact pressures."

Meteorites often contain organic chemicals not related to life that are resistant to the pressures of massive impacts.

So far, there has been little evidence of organics found that would suggest any kind of life has ever existed on Mars, but this new research provides an insight to what could be a previously overlooked complication in that search for life.

"We've literally only scratched the surface of Mars in our search for life, but so far the results have been inconclusive," said Mark Sephton of Imperial College London. "Rocks excavated through meteorite impacts provide scientists with another unique opportunity to explore for signs of life, without having to resort to complicated drilling missions. Our study is showing us is that we may need to be nuanced in our approach to the rocks we choose to analyse."

Rather than relying on computer simulations of meteorite impacts, the researchers used a piston cylindrical device to recreate the pressures and temperatures associated with a range of impact energies on various materials. They will continue to carry out these lab tests to see what energies give hypothetical Mars life the best chance of leaving their biological signature and which will pulverize their biology into oblivion.

Read more at Discovery News

Galápagos faces first-ever bird extinction

This is an adult male Galápagos Vermilion Flycatcher on Isabela Island, Galápagos. This species of Vermilion Flycatcher is not extinct, unlike its close relative, the San Cristóbal Island Vermilion Flycatcher.

Scientists have discovered a new species of colorful songbird in the Galápagos Islands, with one catch: it's extinct. Researchers from the California Academy of Sciences, San Francisco State University (SFSU), the University of New Mexico (UNM), and the San Francisco Bay Bird Observatory (SFBBO) used molecular data from samples of museum specimens to determine that two subspecies of Vermilion Flycatchers, both found only in the Galápagos, should be elevated from subspecies to full species status. One of these newly recognized species -- the characteristically smaller San Cristóbal Island Vermilion Flycatcher -- hasn't been seen since 1987 and is considered to be the first modern extinction of a Galápagos bird species. The findings were published online earlier this May in the journal Molecular Phylogenetics and Evolution.

"A species of bird that may be extinct in the Galápagos is a big deal," says Jack Dumbacher, co-author and Academy curator of ornithology and mammalogy. "This marks an important landmark for conservation in the Galápagos, and a call to arms to understand why these birds have declined."

The study examined the complex evolutionary history of Vermilion Flycatchers by using advanced genetic techniques. In the absence of living tissue, the team turned to the California Academy of Sciences, which houses the largest collection of Galápagos bird specimens in the world. Specimens collected and preserved over 100 years ago allowed the team to carry out DNA sequencing and piece together an evolutionary history of the species.

Vermilion Flycatchers exhibit a complex evolutionary history having branched from an ancestral population into twelve recognized subspecies with ranges that span across the Americas and the Galápagos Islands. This study compares their evolutionary history against the way scientific authorities currently classify the species (and subspecies) to look for any inconsistencies.

"Access to museum collections such as the Academy's for pursuing these types of studies is invaluable," says Christopher Witt, study co-author and associate professor of biology at the University of New Mexico. "Preserved specimens can provide the crucial links needed to better understand how life on Earth evolved."

Two subspecies of the Vermilion Flycatcher, both found only in the Galápagos, were determined to be so genetically distinct that the team elevated them to full species status: Pyrocephalus nanus (throughout most of the Galápagos) and Pyrocephalus dubius (only on the island of San Cristóbal). The latter -- significantly smaller and subtly different in color from the other species -- is commonly known as the San Cristóbal Vermilion Flycatcher and hasn't been seen since 1987.

"Wouldn't it be great if the San Cristóbal Vermilion Flycatcher weren't extinct? No one is looking, I'm pretty sure of that," says Alvaro Jaramillo, study co-author and biologist at the San Francisco Bay Bird Observatory. Searches for the San Cristóbal Vermilion Flycatcher have turned up no evidence so far of its existence on the easternmost island of the archipelago, the only place on Earth it is known to have existed. But Jaramillo claims we shouldn't be so quick to give up on future sightings. "At the very least, this discovery should motivate people to survey and see if there are any remaining individuals of the species hanging on that we don't know about."

What exactly drove the San Cristóbal Vermilion Flycatcher to extinction remains unknown, but two invasive threats to the archipelago likely played a part: rats and parasitic flies (Philornis downsi). Rats often climb into nests to eat bird eggs, while the parasitic fly can kill growing chicks. These invasive species are severely impacting the remaining populations of Vermilion Flycatchers in the Galápagos, with some islands no longer hosting populations that once thrived there.

The Galápagos have been renowned for their species diversity since Charles Darwin -- an honorary Academy member inducted in 1872 -- described the islands' biodiversity in vivid detail through his writings. Despite the lasting connection between Darwin's landmark work on evolutionary biology and the iconic islands, conserving Galápagos biodiversity remains a challenge.

Read more at Science Daily

Specialized life forms abound at Arctic methane seeps

This image shows a chemosymbiotic worm (Siboglinidae) from Bjørnøyrenna crater field. The siboglinids are dependent on microbes for their nutrition. This successful symbiosis relies on the microbes to convert the methane to organic material that provides energy for the worms.

Cold seeps are places where hydrocarbons, mostly methane, emanate from the sea floor. Unlike the hydrothermal vents, the fluids and bubbles are no hotter than the surrounding seawater, thus the name.

But like the hydrothermal vents, cold seeps can support high densities of specialized life forms through a process called chemosynthesis.

These seeps can dramatically influence many aspects of the overall seabed community, even in the frigid and dark Arctic Ocean, new study featured in Marine Ecology Progress Series shows.

"For the first time, we have documented that methane seepage clearly influences faunal communities on the bottom of the ocean in high Arctic areas around Svalbard Archipelago." says CAGE PhD candidate Emmelie Åström who is the lead author of the study.

Plenty but not diverse

Many cold seeps have recently been discovered and mapped on the Arctic shelf of Western Svalbard and Barents Sea. These are connected to melting of methane hydrate, an ice-like substance that forms, and is stable, under the sea floor in cold temperatures and under high pressure.

The study found that methane seeps have a strong localized influence on the abundance and diversity of benthic organisms. The total biomass at seepage sites was significantly higher around the cold seeps compared to non-seepage sites nearby.

"However even though there was a lot of life around those seeps, most of it was composed of a few species that are highly tolerant of the difficult, methane-rich environments, or even more specially adapted to thrive on methane as an energy source. This led to a substantially lower diversity of species at the cold seeps," says Åström.

Chemosynthesis -- a successful life strategy

Åström and colleagues discovered dense fields of chemosymbiotic worms, so-called Siboglinids, around the cold seeps. These are cousins to the dramatic and huge hydrothermal vent worms.

The siboglinids are dependent on microbes for their nutrition. This successful symbiosis relies on the microbes to convert the methane to organic material that provides energy for the worms.

"Our study shows that the effect of these Arctic methane seeps on life at the sea bottom can be strong but is highly localized, reflecting strong gradients associated to the focused methane emission. This means that the environment changes quickly. The organisms living here have to be flexible and tolerate large changes." Emmelie Åström points out.

Cold seeps can be difficult to spot in contrast to dramatic black smokers of hydrothermal vents. But the observations of specialized -- life forms surrounding them may give scientists an indication on location and the amount of methane release.

Read more at Science Daily

Stone age hunters really did hunt well by throwing stones

Previous research has suggested that the spheroids were used as percussive tools for shaping or grinding other materials; however most of the objects analysed by the team had weights that produce optimal levels of damage from throwing, rather than simply being as heavy as possible. This suggests that they could have been selected by Stone Age hunters to be used as projectile weapons.

Stone objects collected by prehistoric hunters were effective as throwing weapons to hunt animals, research at Leeds Beckett University reveals.

The research, published in the latest edition of Scientific Reports, shows that stone objects collected by prehistoric humans could inflict considerable damage to large animals over distances of up to 25 metres.

The researchers, led by Dr Andrew Wilson, an expert in perception, action and embodied cognition at Leeds Beckett, alongside Associate Professor Qin Zhu from the University of Wyoming, Professor Lawrence Barham and Professor Ian Stanistreet from the University of Liverpool, and Professor Geoffrey Bingham from Indiana University, analysed a sample of 55 spheroids (ball-shaped stone objects found in African archaeological sites) from the Cave of Hearths in the Makapan Valley in South Africa.

Using research on the perception of affordances (the possibility of an action on an object or environment) for maximum distance and therefore maximum speed and damage throwing, the researchers simulated the projectile motions the spheroids would undergo if thrown by an expert. These simulations were then used to estimate the probability of these projectiles causing damage to a medium-sized prey animal such as an impala. The researchers found that 81% of the stones analysed could have inflicted worthwhile damage over distances of up to 25 metres.

Previous research has suggested that the spheroids were used as percussive tools for shaping or grinding other materials; however most of the objects analysed by the team had weights that produce optimal levels of damage from throwing, rather than simply being as heavy as possible. This suggests that they could have been selected by Stone Age hunters to be used as projectile weapons.

Dr Andrew Wilson explained: "Whilst other animals have been known to throw objects on occasion, none can match the speed, accuracy and distances that a trained human can achieve. Humans are uniquely specialised for throwing, both anatomically and psychologically. Throwing has played a vital role in our evolutionary past, enabling us both to hunt prey and to compete with other carnivores to scavenge carcasses. The ability to damage or kill prey at a distance not only expands the range of foods available, but also reduces the risk of close confrontation with dangerous prey.

"Before the development of throwing spears, our ancestors were faced with the task of finding and using objects suitable for hunting and defence. Imagine a human, searching for an object to throw so as to cause the most damage possible to a prey animal or a competitor. Their job is to find an object of an optimum size and weight: large and heavy enough to fly far and cause damage, but not too large or heavy as to interfere with producing the high speed throw required for distance and damage. This is a perceptual task: the person needs to perceive throwing-relevant affordance properties of objects and be able to discriminate between objects that vary in those properties. Other research has shown modern humans to be exceptionally good at this task.

"This study applies research about how modern humans perceive the throwing affordances of objects, to provide a mathematical analysis of the stones found at the Cave of Hearths and evaluate the of these objects as projectiles for throwing."

Professor Larry Barham, Department of Archaeology, Classics and Egyptology at the University of Liverpool, added: "Archaeologists have long puzzled over what these round stones were used for -- they're about the size of a tennis ball but much heavier. This study shows that they are good hunting weapons when thrown overhand, and we know early humans could throw with power and accuracy. [Their upper body anatomy was much like ours.] The artefacts in this study were carried to the cave which suggests these people selected the stones for their size, shape and weight. Our modelling shows that these stones could have been used for hunting and that's an important piece of information given these ancestors lived before the invention of spears or the bow and arrow."

Read more at Science Daily

Origin of the long body of snakes

This image shows a snake embryo.

For many years, researchers have been trying to understand the origin of the exceptionally long trunks that characterize the body of snakes. This is a mystery in terms of animal development that can shed light on the mechanisms controlling the tissues that form the trunk, including the skeleton and the spinal cord. A research team led by Moisés Mallo from Instituto Gulbenkian de Ciência (IGC, Portugal) now discovered the key factor that regulates trunk development in vertebrates and explains why snakes have such a strikingly different body. These findings, published in the latest edition of Developmental Cell and highlighted in its cover, may open new avenues to the study of spinal cord regeneration.

Despite obvious differences in size and shapes observed among different vertebrate animals, they all have bodies with a head and neck, a trunk and a tail. It is the relative size of each of these body sections what makes a large part of the body differences among these animals. Still, all vertebrates develop by consecutive phases, forming each region of the body in a specific order, from head to tail. The development is guided by genetic instructions that inform the beginning and the end of each body region's formation. Moisés Mallo's laboratory has been trying to crack the genetic code that controls trunk and tail development in vertebrates. In order to achieve it, they studied mice that had particularly long or especially short trunks. "We thought that the analysis of these animals could give us the key to unveil the code of trunk formation," says Moisés Mallo.

Their experiments led to the surprising finding that the key controller of trunk development was the Oct4 gene, one of the essential regulators of stem cells. Since many other vertebrates also have Oct4, this gene could play similar roles in other animals and might even be responsible for the exceptionally long trunks of snakes. Rita Aires, first author of this study, explains: "We had found that Oct4 is the switch that leads to trunk formation, still we couldn't explain the different trunk length observed in vertebrates, particularly in snakes. Therefore, we tested if this switch was being turned on or off during different periods of embryonic development in snakes compared to mice."

The researchers discovered that the Oct4 gene was indeed kept active during a longer period of time in snakes when compared to other animals. They also showed that this resulted from changes in the snake genome that happened during reptile evolution, which placed the Oct4 gene next to a DNA region that keeps this gene in an "ON" state during long periods of embryonic development.

"The formation of different body regions works as a strong-arm contest of genes. Genes involved in trunk formation need to start ceasing activity so that the genes involved in tail formation can start working. In the case of snakes, we observed that the Oct4 gene is kept active during a longer period of embryonic development, which explains why snakes have such a long trunk and a very short tail," says Rita Aires.

Read more at Science Daily

Tracing the evolution of bird reproduction

Birds' reproductive strategies have gone through a series of stages, from dinosaurs to today.

What really did come first -- the chicken or the egg? Birds' reproductive biology is dramatically different from that of any other living vertebrates, and ornithologists and paleontologists have long wondered how and when the unique features of bird reproduction originated. A new Review in The Auk: Ornithological Advances examines answers from three sources -- modern birds, fossils of primitive birds, and fossils of the dinosaurs from which birds are descended -- to shed new light on the subject.

All modern birds share certain reproductive features, such as a single functional ovary and the practice of incubating their eggs through direct contact. Analysis of the bird family tree also suggests that early birds built simple, open nests on the ground and that their young were "precocial," meaning they were well-developed and almost ready to fend for themselves when they hatched. Those dinosaurs close to the ancestry of birds shared some of these traits, but they had two functional reproductive tracts, and their eggs were smaller relative to their body size and more elongated than those of modern birds.

Fossils of primitive birds and eggs from the Mesozoic era place them midway between their dinosaur ancestors and their modern descendants, with eggs between those of pre-avian dinosaurs and modern birds in term of size and shape. In this way, David Varricchio and Frankie Jackson of the Montana State University are able to trace the evolution of bird reproduction through a series of distinct stages, from pre-avian dinosaurs to the birds of today.

"Reproduction in modern birds is distinct among living vertebrates. Many aspects of this reproduction mode trace their origin to theropod dinosaurs such as Oviraptors and Troodontids, but not really beyond them to more distantly related dinosaurs," according to Varricchio. "Interestingly, reproduction in the most common group of Mesozoic birds is very similar to that of these dinosaurs, and so still differs from modern birds. Consequently, modern birds stand apart from Mesozoic birds, and perhaps this contributed to their surviving the end-Cretaceous extinction event."

From Science Daily

Researchers find brain's 'physics engine'

The location of the 'physics engine' in the brain is highlighted in color in this illustration.

Whether or not they aced the subject in high school, human beings are physics masters when it comes to understanding and predicting how objects in the world will behave. A Johns Hopkins University cognitive scientist has found the source of that intuition, the brain's "physics engine."

This engine, which comes alive when people watch physical events unfold, is not in the brain's vision center, but in a set of regions devoted to planning actions, suggesting the brain performs constant, real-time physics calculations so people are ready to catch, dodge, hoist or take any necessary action, on the fly. The findings, which could help design more nimble robots, are set to be published in the journal Proceedings of the National Academy of Sciences.

"We run physics simulations all the time to prepare us for when we need to act in the world," said lead author Jason Fischer, an assistant professor of psychological and brain sciences in the university's Krieger School of Arts and Sciences. "It is among the most important aspects of cognition for survival. But there has been almost no work done to identify and study the brain regions involved in this capability."

Fischer, along with researchers at Massachusetts Institute of Technology, conducted a series of experiments to find the parts of the brain involved in physical inference. First they had 12 subjects look at videos of Jenga-style block towers. While monitoring their brain activity, the team asked the subjects either to predict where the blocks would land should the tower topple, or guess if the tower had more blue or yellow blocks. Predicting the direction of falling blocks involved physics intuition, while the color question was merely visual.

Next, the team had other subjects watch a video of two dots bouncing around a screen. They asked subjects to predict the next direction the dots would head, based either on physics or social reasoning.

With both the blocks and dots, the team found, when subjects attempted to predict physical outcomes, the most responsive brain regions included the premotor cortex and the supplementary motor area -- the brain's action planning areas.

"Our findings suggest that physical intuition and action planning are intimately linked in the brain," Fischer said. "We believe this might be because infants learn physics models of the world as they hone their motor skills, handling objects to learn how they behave. Also, to reach out and grab something in the right place with the right amount of force, we need real-time physical understanding."

In the last part of the experiment, the team asked subjects to look at short movie clips -- just to look; they received no other instructions -- while having their brain activity monitored. Some of the clips had a lot of physics content, others very little. The team found that the more physical content in a clip, the more the key brain regions activated.

"The brain activity reflected the amount of physical content in a movie, even if people weren't consciously paying attention to it," Fischer said. "This suggests that we are making physical inferences all the time, even when we're not even thinking about it."

The findings could offer insight into movement disorders such as apraxia, as it's very possible that people with damage to the motor areas of the brain also have what Fischer calls "a hidden impairment" -- trouble making physical judgments.

Read more at Science Daily

First Bell Beaker earthwork enclosure found in Spain

The newly discovered circular earthwork enclosure La Loma del Real Tesoro II (near Carmona).

Archaeologists from the Tübingen collaborative research center ResourceCultures have discovered an earthwork enclosure in southern Spain dating from the Bell Beaker period of 2,600 to 2,200 BCE. The complex of concentric rings may have been used for holding rituals; such earthwork enclosures have previously only been found in the northern half of Europe.

In a ResourceCultures field study, researchers sought information on how the inhabitants of southern Spain dealt with their region's resources during the Copper Age and what effects that had on society, trade relations and migration in the area. Archaeologists have known since the middle of the nineteenth century that today's Valencina de la Concepción outside Seville was at the heart of an important Copper Age settlement. In 1860, the Dolmen de la Pastora -- a long megalith tomb -- was first identified; it was described by archaeologists in 1868. It was the region's first big find from the Copper Age or Chalcolithic, which preceded the Bronze Age.

The nearby settlement of Valencina was supported by farming and stockraising on the fertile coastal plain. It is Spain's largest known Copper Age settlement -- of over 400 hectares. Grave goods found at the site show that the people of Valencina traded with Copper Age cultures far away: items include exotic luxury wares such as elephant tusks from Africa and the Middle East, and amber beads from northern Europe.

In return, it is likely they traded copper ore from the mountains behind Valencina. It is uncertain to what extent the city traded with areas further inland and exactly where trade routes and migrations ran. Tübingen archaeologists headed by Professor Martin Bartelheim plan to carry out fieldwork which will shed light on these little-researched issues.

The archaeologists discovered the earthwork enclosure some 50 kilometers east of Valencina. Sur-veying the land in August 2015, they found circular earthworks enclosing about six hectares. Exca-vations at the site yielded bones, sherds and jewelry; radiocarbon dating and comparative analysis confirmed the site was used during the Bell Beaker Culture (2,600 to 2,200 BCE). The Bell Beaker Culture is named after the characteristic shape of the vessels it produced.

Just what the site was used for is still a mystery. It consists of several circular trenches with entrance-like openings at regular intervals. In the center was a deep, circular hole some 19 meters wide. In it, the archaeologists found large clay bricks with burn marks on it which may have served a ritual purpose. But they did not find human remains or indications of continuous settlement after the Copper Age -- suggesting the site was used intensively for a relatively short period.

The researchers believe this circular earthwork enclosure, so unusual for the region, could have been used for religious purposes. Doctoral candidate in the CultureResources group, Javier Escudero Carrillo, says "the structure is very unusual for Spain, other circular earthworks like this are only found north of the Alps; but most are more than a thousand years older than this site. The stony ground here is not good for farming, but the site is strategically located near an ancient fort on the Guadalquivir River near the ore-rich Sierra Morena mountains, where copper and other valuable minerals were mined. Trails link the site with the fertile plain of Carmona, so that we may assume it was used by many passing through. That fits well with the interpretation of a site used for religious purposes."

Read more at Science Daily

Moving the Earth's Prime Meridian

Tourists visiting the Airy meridian at the Royal Observatory in England (dotted line) stand on the historic location of the prime meridian, but improving technology reveals its actual location lies to the east (solid line).

Tourists who want to take photographs at the prime meridian often stand at the Royal Observatory in Greenwich, England. But improved technology reveals that the actual site of the imaginary north-south line that cuts the Earth in half at zero degrees longitude lies 334 feet (102 meters) east of the historical marker. The increased accuracy means that many historical coordinates are sometimes off by significant distances.

"Most people stand on the stripe and have their picture taken, with the sundial in the background," said Ken Seidelmann, an astronomer at the University of Virginia. "If they stood there with their GPS receiver, it wasn't zero degrees."

Seidelmann learned that many people reported that their GPS devices listed the line of zero degrees longitude in a completely different location than at the landmark. He was part of a team of scientists who found that the prime meridian had shifted because of improved measurements rather than changes in the Earth's surface. Seidelmann presented the results at the American Astronomical Society's Division on Dynamical Astronomy in Nashville, Tennessee, in May.

GPS trumps the stars

In 1675, when England's Royal Observatory was founded, Earth was thought to be perfectly spherical. Later observations revealed that the planet, like most others, has a slight bulge around its center, which affects how gravity tugs at things across the globe. In 1884, the observatory's Airy Transit Circle, an instrument that measures star positions and determines local time, was set at what was then considered the calculated location of the prime meridian, and that's where most photographs are taken today.

To officially set the line of longitude, scientists relied on an instrument known as a photographic zenith tube, a telescope using the reflection of light off of mercury to determine the imaginary vertical line running toward Earth's core. But Earth's crust isn't perfectly flat; mountains and other terrain, along with the central bulge, affect the pull of gravity and distort calculations of the tug from the center of the Earth. The prime meridian, which sets the boundaries for time zones and the baseline for other lines of longitude around the globe, suffered from these variations.

Rather than using a basin of mercury, modern technology relies on precise measurements of the line running from the crust to the center of the Earth. To make those measurements, modern scientists incorporate variations in Earth's rotation, atomic clocks, lasers bounced from Earth to the moon and back, and GPS satellites.

"Better technology came along and phased out the optical methods," Seidelmann said.

In 1984, the International Time Bureau (BIH) redefined the location of the prime meridian based on refined measurements of the Earth's center. Thanks to satellites, the location of Earth's center of mass has been measured with an accuracy of about the size of a dime; in 1984, the accuracy was slightly less precise. Faced with the decision of whether to shift the longitudes of the Earth or its time zones to match modern measurements, the BHI chose to have its newly applied system shift the map rather than the time zones.

"They chose not to have a discontinuity in time and let the longitudes correct themselves," Seidelmann said.

Seidelmann's research was published in the Journal of Geodesy.

Disappearing telescopes

After determining why the prime meridian had shifted, Seidelmann and his colleagues investigated how longitudes around the world were affected by the change. After determining the locations of observatories in a variety of nations, as described in historical references, they sent colleagues around the world out to determine whether the longitudes of the antique instruments were all off by 334 feet.

Read more at Discovery News

Cardinals 'Super Suppressors' of West Nile Virus

Authors of a new study took a closer look at a puzzling circumstance in Georgia: low rates of human infection with the West Nile virus (WNV), even as about a third of Atlanta's birds carry the disease.

The same situation -- many infected birds, not so many infected people -- applied to the broader American southeast, a team of researchers from Emory University, Texas A&M, the University of Georgia and Georgia's department of transportation noted.

Indeed, they said, Georgia's WNV infection rate, over the last 15 years, was only about 3 people per 100,000.

To try to shed light on the discrepancy, the scientists spent three years testing birds and mosquitoes for WNV in Atlanta, analyzing the blood of the insects to determine on which birds they had fed.

The scientists were keeping a sharp eye for the number of American robin infections. They consider that species a "super spreader" of WNV, for its capacity to store enough of the virus in its blood to pass along to other mosquitoes.

While robins were certainly carriers, the researchers found a twist in the tale, one concerning a favorite of backyard birders everywhere: the cardinal.

"What we found is that, for some unknown reason, around the middle of July, mosquitoes in Atlanta seem to decide that they have had their fill of robins and they switch to feeding on cardinals," said the study's lead author, Rebecca Levine, in a statement.

"But cardinals, even though they can be infected with West Nile virus, are much less likely to have enough virus circulating in their blood to transmit the disease back to feeding mosquitoes," said Levine, now with the U.S. Centers for Disease Control and Prevention but at Emory University during the research. "That is why we called them 'super suppressors'."

Levine and her colleagues aren't sure yet why this sudden dietary change occurs in the insects, a shift that seems to be helping Atlanta's citizens.

Humans become infected with WNV through mosquito bites, which the insects pick up when they bite infected birds. According to the World Health Organization most infected humans don't even show symptoms, but in rare cases the virus can be fatal.

Many things could determine how WNV is passed between birds and mosquitoes, and whether that puts humans at greater or lesser risk, the researchers said.

Changes in how the birds roost, or defensive behaviors are potential factors, they said.

Read more at Discovery News

Most volcanic activity on Mercury stopped about 3.5 billion years ago

Enhanced color image of Mercury. The bright, circular deposit in the upper center of the image is an enormous effusive volcanic deposit, situated within the largest impact crater on the planet, the Caloris basin.

New research from North Carolina State University finds that major volcanic activity on the planet Mercury most likely ended about 3.5 billion years ago. These findings add insight into the geological evolution of Mercury in particular, and what happens when rocky planets cool and contract in general.

There are two types of volcanic activity: effusive and explosive. Explosive volcanism is often a violent event that results in large ash and debris eruptions, such as the Mount Saint Helens eruption in 1980. Effusive volcanism refers to widespread lava flows that slowly pour out over the landscape -- believed to be a key process by which planets form their crusts.

Determining the ages of effusive volcanic deposits can give researchers a handle on a planet's geological history. For example, effusive volcanism was active a few hundred million years ago on Venus, a few million years ago on Mars, and it still takes place on Earth today. Until now, the duration of effusive volcanic activity on Mercury, made of the same materials as these other planets, had not been known.

NC State assistant professor and planetary geologist Paul Byrne and colleagues determined when the bulk of Mercury's crust-forming volcanism ended by using photographs of the surface imaged by NASA's MESSENGER mission. Because there are no physical samples from the planet that could be used for radiometric dating, the researchers used crater size-frequency analysis, in which the number and size of craters on the planet's surface are placed into established mathematical models, to calculate absolute ages for effusive volcanic deposits on Mercury.

According to their results, major volcanism on Mercury stopped at around 3.5 billion years ago, in stark contrast to the volcanic ages found for Venus, Mars and Earth.

"There is a huge geological difference between Mercury and Earth, Mars or Venus," Byrne says. "Mercury has a much smaller mantle, where radioactive decay produces heat, than those other planets, and so it lost its heat much earlier. As a result, Mercury began to contract, and the crust essentially sealed off any conduits by which magma could reach the surface.

"These new results validate 40-year-old predictions about global cooling and contraction shutting off volcanism," Byrne continues. "Now that we can account for observations of the volcanic and tectonic properties of Mercury, we have a consistent story for its geological formation and evolution, as well as new insight into what happens when planetary bodies cool and contract."

Read more at Science Daily

How the Vikings started the worldwide distribution of gaited horses

Ambling Iceland pony during World Championship.

Some horses have special gaits, which are more comfortable for the rider than walk, trot or gallop. Now, a study by an international research team under the direction of the Leibniz Institute for Zoo and Wildlife Research (IZW) in Berlin revealed that these gaited horses most likely originated in the 9th century medieval England. From there they were brought to Iceland by the Vikings and later spread all over Europe and Asia. These findings were published in the current issue of the journal "Current Biology."

Walk, trot and gallop are the gaits which all horses can master. However, riders who want to sit in their saddle more comfortably while still making good time on long journeys would benefit from choosing gaited horses. They are able to perform special gaits, like the ambling or pacing, which are typical for Icelandic horses and allow for a smoother ride. Responsible for this ability is a mutation in the DMRT3 gene, which was recently shown by a study with over 4,000 horses from different breeds. To investigate the history of gaited horses the scientist analysed this mutation in the genome of 90 horses from the Copper Age (6000 BC) to the Middle Ages (11th century). They detected the mutation in samples of two English horses from 850 -- 900 AD and more frequently in Icelandic horses dating to the 9th -- 11th century. Most likely the first gaited horses appeared in medieval England and were then transported to Iceland by the Vikings. Horses have existed in Iceland since 870 BC. In contrast, no European (Scandinavia included) or Asian horse of the same period carrying the mutation for the alternative gaits was found.

It is improbable that the English and Icelandic gaited horse populations developed independently from each other in such a short time. "It is much more likely, that the first horses ever imported to Iceland already carried the mutation for alternative gaits. The Vikings recognised the value of the gaited horses and preferentially selected for this trait -- thereby laying the foundation for the worldwide distribution," explains Arne Ludwig, geneticist at the IZW. Historic sagas also suggest that Icelandic horses exhibited the ability for alternative gaits at a very early stage. Although the origin of the Icelandic horse is not fully resolved, the general assumption is that they came to the island together with the Vikings. However, since the mutation was not found in Scandinavian horses of the 9th century, horses from other regions must have been brought to Iceland as well.

Read more at Science Daily

Archaeology team makes world-first tool discovery

One of the stone tools (a blade that tested positive for rhino residue).

How smart were human-like species of the Stone Age? New research published in the Journal of Archaeological Science by a team led by paleoanthropologist April Nowell of the University of Victoria reveals surprisingly sophisticated adaptations by early humans living 250,000 years ago in a former oasis near Azraq, Jordan.

The research team from UVic and partner universities in the US and Jordan has found the oldest evidence of protein residue -- the residual remains of butchered animals including horse, rhinoceros, wild cattle and duck -- on stone tools. The discovery draws startling conclusions about how these early humans subsisted in a very demanding habitat, thousands of years before Homo sapiens first evolved in Africa.

The team excavated 10,000 stone tools over three years from what is now a desert in the northwest of Jordan, but was once a wetland that became increasingly arid habitat 250,000 years ago. The team closely examined 7,000 of these tools, including scrapers, flakes, projectile points and hand axes (commonly known as the "Swiss army knife" of the Paleolithic period), with 44 subsequently selected as candidates for testing. Of this sample, 17 tools tested positive for protein residue, i.e. blood and other animal products.

"Researchers have known for decades about carnivorous behaviours by tool-making hominins dating back 2.5 million years, but now, for the first time, we have direct evidence of exploitation by our Stone Age ancestors of specific animals for subsistence," says Nowell. "The hominins in this region were clearly adaptable and capable of taking advantage of a wide range of available prey, from rhinoceros to ducks, in an extremely challenging environment."

"What this tells us about their lives and complex strategies for survival, such as the highly variable techniques for prey exploitation, as well as predator avoidance and protection of carcasses for food, significantly diverges from what we might expect from this extinct species," continues Nowell. "It opens up our ability to ask questions about how Middle Pleistocene hominins lived in this region and it might be a key to understanding the nature of interbreeding and population dispersals across Eurasia with modern humans and archaic populations such as Neanderthals."

Read more at Science Daily

Floating 'Alien' Orb Spotted by Fisherman

A huge, floating orb — one that looks more like an alien object than anything typically found in the ocean — left a fisherman perplexed when he came across it in the waters off the coast of Australia. But despite its strange appearance, the bobbing monstrosity has an earthly explanation: Researchers said it's a bloated whale carcass.

Fisherman Mark Watkins spotted the ballooned carcass about 30 miles (50 kilometers) southwest of Bunbury, Australia. Watkins said he thought it could be another boat or a balloon, but as he got closer to the orb, a pungent odor revealed the object's true identity: whale.

The species of the whale was not officially identified, but the texture of its belly suggests it was most likely a humpback or southern right whale, reported Mother Nature Network.

And though whale carcasses may seem like an unusual sight, they are a challenging problem. Marine biologist Andrew David Thaler told National Geographic in 2014 that the bloat of a dead, beached whale comes from pent up gas released as the animal's internal organs and stomach contents decompose. (Thaler created the website Has the Whale Exploded Yet? to update people on the status of a 375,000-lb., or 170,000 kilograms, beached blue whale in Newfoundland, Canada.) When jostled or manipulated, a whale carcass can explode, spewing whale guts and emitting a punishing smell.

"Imagine a jar of bacon grease that you leave out in the sun for weeks. Now imagine that odor is so potent that it clings to everything you own. ... Decomposing whale is one of the worst smells in the world," Thaler told National Geographic.

Beached whales do pose a threat to coastal communities. In 2014, an unusually high number of Newfoundland blue whales died and washed ashore, including the specimen Thaler was monitoring, after being trapped in shifting ice patches. If ice shifts in such a way that whales can't surface, the animals are unable to breathe and they can suffocate, reported CTV News. One or two animals are typically trapped in this way each year, but the nine whales that washed up on the Newfoundland coast in the spring of 2014 made for a particularly dramatic year, according to CTV News.

Thaler said the best option in the event of a beaching is to bury the carcass on site and leave it to decompose.

But whale deaths in the ocean, like what Watkins observed, result in a much more natural process. Thaler said scavengers aren't usually able to puncture the whale's thick skin and blubber when the carcass is floating in the sea, and eventually the body will naturally deflate and sink, intact, to the seafloor.

Read more at Discovery News