Bare Feet: Why So Warm (Download Great Podcast)

Bare Feet: Why So Warm

By Eric Sonstroem

Posted April 12, 2012

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What keeps penguin's feet from freezing? Penguins' feet don't freeze because of the blood circulating in them.

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Photo: Bruce McAdam (Flickr)

The circulatory system of a penguin's legs and feet has evolved to lose as little heat as possible.

What keeps penguin’s feet from freezing?
Penguins’ feet don’t freeze because of the blood circulating in them.

The circulatory system of a penguin’s legs and feet has evolved to lose as little heat as possible, while keeping the penguin’s feet just above freezing. One way a penguin’s feet hold onto heat is by restricting the flow of blood in really cold weather. Actually, humans can do this too. That’s why your hands turn whiter in cold weather, there’s less blood in them.

Also, the tops of penguins’ legs work like a kind of natural heat-exchanger, cooling the blood from their bodies on the way to their feet, and heating the blood as it returns to their bodies. The arteries and veins here become very fine and interwoven. That way the feet only get pre-cooled blood, so there’s less heat to lose.

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Antarctica at Risk from Human Activities

 

 Penguins nest. (Credit: © Goinyk Volodymyr / Fotolia)

ScienceDaily (July 12, 2012) — The continent of Antarctica is at risk from human activities and other forces, and environmental management is needed to protect the planet's last great wilderness area, says an international team of researchers, including a Texas A&M University oceanographer, in a paper published in the current issue of Science magazine.

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Mahlon "Chuck" Kennicutt II, professor of oceanography who has conducted research in the area for more than 25 years, says Antarctica faces growing threats from global warming, loss of sea ice and landed ice, increased tourism, over-fishing in the region, pollution and invasive species creeping into the area. One of the longer-term concerns that may present the greatest threat overall is the potential for oil, gas and mineral exploitation on the continent and in the surrounding ocean, the authors note.
Kennicutt says the Antarctic Treaty System that governs the continent has worked well since it was established in 1962 and that 50 countries currently adhere to the treaty, but it is under pressure today from global climate changes and the ever-present interest in the area's natural resources, from fish to krill to oil to gas to minerals.

"Many people may not realize that Antarctica is a like a 'canary in a coal mine' when it comes to global warming, and Antarctica serves as a sort of thermostat for Earth," he points out. "The polar regions are the most sensitive regions on Earth to global warming, responding rapidly, so what happens in Antarctica in response to this warming affects the entire Earth system in many ways that we barely understand," Kennicutt explains. "Antarctica contains over 90 percent of the fresh water in the world, locked up as solid water in its massive ice sheets. Research that develops fundamental knowledge and understanding of these complex systems conducted in and from Antarctica is critical to understanding many of the challenges facing Earth today."

In addition to conducting research in the area, Kennicutt is also president of the Scientific Committee for Antarctic Research (SCAR), formed in 1958 to coordinate international research in the region.
More than twice the size of the United States, Antarctica has no cities, no government and no permanent residents. All who go to Antarctica are short-time visitors, whether they are scientists, personnel that support scientists or tourists. Antarctica is the coldest, driest and windiest location on Earth and is the only continent with no time zones.

"The Antarctic Treaty has worked well for the past 50 years, but we need to rethink how best to protect the continent from a range of growing of threats," Kennicutt adds.

"The treaty forbids oil or gas development, but it's possible that could be challenged in the years to come. Until now, energy companies have shown little interest in exploring the southern reaches of our planet because of the harsh conditions, the distance to market and the lack of technologies make it a very expensive commercial proposition.

"In the 1960s, most believed that drilling on the North Slope of Alaska was not economical, and in less than 30 years, it became one of the world's major sources of oil. Deep-water drilling today is practiced worldwide and subfloor completion technologies are rapidly advancing, so barriers in the past may soon be overcome increasing the threat to Antarctica in the not-so-distant future."
Another problem -- melting ice from several areas of Antarctica -- is a very real concern today, Kennicutt adds.

"A report in the news last week shows that sea-level rise on the east coast of the U.S. is occurring much faster than predicted," he notes.

"As the planet warms and the massive ice sheets break apart and melt, sea levels could continue to rise dramatically, not only in the U.S. but around the world. The ice sheets of Antarctica are known as the 'sleeping giants' in the ongoing debates about climate change and sea level rise. Scientists have only rudimentary understanding of how and when these 'giants' will contribute to sea level in the future."

He adds that the first explorers to Antarctica more than 100 years ago would be surprised to see how things have changed in the region.

For instance, it has been proven there are more than 300 sub-glacial lakes in Antarctica, some of them as big as the Great Lakes, and the huge ice sheets in the area flow like rivers to the ocean. He adds that growing tourism in the area and numerous scientific expeditions suggest that the prospect of permanent human settlements is not out of the question.

"All of these concerns pose serious challenges to conservation and protection efforts in Antarctica," Kennicutt notes.

"The bottom line is that we need to make sure that existing agreements and practices that address and respond to these threats are robust enough to last for the next 50 years, and that they truly provide the necessary protection of Antarctica that we all wish for and that we owe to future generations."

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Story Source:

The above story is reprinted from materials provided by Texas A&M University, via Newswise.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. S. L. Chown, J. E. Lee, K. A. Hughes, J. Barnes, P. J. Barrett, D. M. Bergstrom, P. Convey, D. A. Cowan, K. Crosbie, G. Dyer, Y. Frenot, S. M. Grant, D. Herr, M. C. Kennicutt II, M. Lamers, A. Murray, H. P. Possingham, K. Reid, M. J. Riddle, P. G. Ryan, L. Sanson, J. D. Shaw, M. D. Sparrow, C. Summerhayes, A. Terauds, and D. H. Wall. Challenges to the Future Conservation of the Antarctic. Science, 13 July 2012: 158-159 DOI: 10.1126/science.1222821

Texas A&M University (2012, July 12). Antarctica at risk from human activities. ScienceDaily. Retrieved July 13, 2012, from ­source

Fossil Egg Links Dinosaurs to Modern Birds

Researchers have discovered a series of dinosaur eggs with a unique characteristic: they are oval in shape. The discovery supports the theory that birds and non-avian theropods, dinosaurs from the Cretaceous Period, could have a common ancestor. (Credit: Image courtesy of Universitat Autònoma de Barcelona)

ScienceDaily (July 12, 2012) — Researchers have discovered a series of dinosaur eggs with a unique characteristic: they are oval in shape. The discovery supports the theory that birds and non-avian theropods, dinosaurs from the Cretaceous Period, could have a common ancestor.

Before her death in December 2010, Nieves López Martínez, palaeontologist of the Complutense University of Madrid, was working on the research of dinosaur eggs with a very peculiar characteristic: an ovoid, asymmetrical shape. Together with Enric Vicens, palaeontologist of the Universitat Autònoma de Barcelona, the two scientists conducted an exhaustive analysis of their discovery, recently published in the journal Palaeontology.

The new type of dinosaur egg has been given the scientific name of Sankofa pyrenaica. The eggs were discovered in the Montsec area of Lleida, in two sites located on either side of the Terradets pass in Spain.

The South Pyrenean area is rich in dinosaur egg sites, most of which correspond to sauropod eggs from the upper Cretaceous, dating back more than 70 million years ago. During that period, the area was a coastal area full of beaches and deltas which won land from the sea through sediment accumulation. Sand and mud from that period gave way, millions of years later, to the sandstone and marl where dinosaur remains now can be found. On the beach ridges and flat coastal lands is where a large group of dinosaurs laid their eggs.

The sites where the discoveries were made correspond to the upper Cretaceous, between the Campanian and Maastrichtian periods, some 70 to 83 million years ago. The fossils found belong to small eggs measuring some 7 centimeters tall and 4 cm wide, while the eggshell was on average 0.27mm thick. Most of the eggs found were broken in small fragments, but scientists also discovered more or less complete eggs, which can be easily studied in sections. The eggs found at the sites all belong to the same species. The main difference when compared to other eggs from the same period is their asymmetrical shape, similar to that of chicken eggs. The more complete samples clearly show an oval form rarely seen in eggs from the upper Cretaceous period and similar to modern day eggs.
Their shape is a unique characteristic of theropod eggs from the upper Cretaceous period and suggests a connection with bird eggs. Non avian dinosaur eggs are symmetrical and elongated.

Asymmetry in bird eggs is associated to the physiology of birds: they take on this shape given the existence of only one oviduct which can form only one egg at a time. In this case the isthmus, the region in the oviduct creating the eggshell membrane, is what gives the egg its asymmetrical shape.

Thanks to this shape, the wider end contains a bag of air which allows the bird to breathe in the last stages of its development. This evolutionary step was still relatively underdeveloped in dinosaurs.
Thus, the egg discovered by UCM and UAB researchers may represent the missing link between dinosaurs and birds. Only one other egg, discovered in Argentina and corresponding to a primitive bird from the same period, has similar characteristics. The discover supports the theory that non avian theropods, the dinosaurs of the Cretaceous period, and birds could have had a common ancestor.

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Story Source:

The above story is reprinted from materials provided by Universitat Autònoma de Barcelona.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Nieves López-Martínez, Enric Vicens. A new peculiar dinosaur egg, Sankofa pyrenaica oogen. nov. oosp. nov. from the Upper Cretaceous coastal deposits of the Aren Formation, south-central Pyrenees, Lleida, Catalonia, Spain. Palaeontology, 2012; 55 (2): 325 DOI: 10.1111/j.1475-4983.2011.01114.x

Universitat Autònoma de Barcelona (2012, July 12). Fossil egg links dinosaurs to modern birds. ScienceDaily. Retrieved July 13, 2012, from source­ 

King Penguin Colony Getting Used to Humans

Jeanna Bryner, LiveScience Managing Editor

The researchers aren't sure if the king penguins are acclimating to humans and so don't get stressed when in their presence or if human presence weeded out those stress-sensitive penguins, leaving the copers behind. CREDIT: Vincent Viblanc View full size image

 
Updated Wednesday, July 11

Scientists studying king penguins on a sub-Antarctic island, along with tourists, may be stressing the waddling, flightless birds, new research suggests. However, it seems the penguins are getting used to their human visitors.

The new study reveals how more than 50 years of human presence, or the time since a permanent research station was set up, on Possession Island, has impacted a major colony of breeding king penguins (Aptenodytes patagonicus), called the "Baie du Marin" colony. Research reported last year on these penguins found that flipper tagging was linked with fewer chicks and a lower survival rate for the birds compared with untagged king penguins.


Turns out, according to the new study, penguins that are used to humans being around didn't get too upset by noise and human-presence stressors, though capturing these penguins for scientific measurements did cause a stress surge, according to the study published this week in the journal BMC Ecology.


"A central question for ecologists is the extent to which anthropogenic disturbances (e.g. tourism) might impact wildlife and affect the systems under study," lead researcher Vincent Viblanc of the University of Lausanne in Switzerland said in a statement. "One of the major pitfalls of such research is in forgetting that, from the perspective of the wildlife studied, tourism and scientific research are not two worlds apart."

In some ways, this island is perfect for studying stress in penguins. That's because some parts of the Baie du Marin colony have been exposed more intensely to humans than others, Viblanc told LiveScience. In disturbed parts of the colony scientists and tourists, sometimes in groups of tens, come into the presence of the penguins. A small number, about 50 birds, in this area are captured and handled by scientists one to five times each year. Meanwhile, another part of the colony is relatively undisturbed, Viblanc said, with one to two visits per week by scientists.

 

The king penguins come ashore on the sub-antarctic island to breed each year. Hundreds of the penguins waddle onto land to find a mate, and hopefully, make some chicks.
CREDIT: Pierre Bize

Viblanc and his colleagues compared 15 breeding penguins in these disturbed areas with 18 undisturbed penguins. All of the penguins were brooding a chick between 2 days and a month old.
To get a sense of the penguins' stress levels, the researchers measured their heart rates in response to three stressors: two low-intensity stressors that included a human approach to about 33 feet (10 meters) and a loud noise, meant to mimic tourists, scientists and noises from machines operating on the outskirts of the colony. The high-intensity stressor involved capturing a penguin to simulate what happens when scientists take direct measurements.

Compared with penguins from undisturbed areas, the disturbed penguins were less stressed by noise and approaching humans; the increase in heart rate above resting levels was much lower, 81 percent and 74 percent lower, in birds used to humans when they heard stressful sounds and saw humans approaching, respectively.

However, following capture, the human-acclimated penguins' maximum relative heart rate increased 42 percent higher than it did for undisturbed birds, though it recovered faster afterwards.
"Penguins habituate to the distant presence of human observers in disturbed areas, whereas they do not habituate to being captured," Viblanc wrote in an email to LiveScience. "This makes sense, as from an adaptive perspective, stress responses enable the organism to deal with life-threatening situations. Captures may indeed be assimilated as predation events from the birds, whereas the distant presence of observers poses no immediate threat."

Their findings can't tease out whether the lower heart-rate numbers in the highly disturbed areas are a result of penguins becoming habituated to human presence or if they are the result of a selection process. For instance, have penguins whose "animal personalities" are more susceptible to stress deserted these areas, leaving behind those that are better at coping, the researchers wonder.

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'Depraved' sex acts by penguins shocked polar explorer

 

9 June 2012  

  

By Matt McGrath Science reporter, BBC World Service

Scientists now understand the biological reasons for behavior Dr Levick considered to be "depraved"

Accounts of unusual sexual activities among penguins, observed a century ago by a member of Captain Scott's polar team, are finally being made public.

Details, including "sexual coercion", recorded by George Murray Levick were considered so shocking that they were removed from official accounts.

However, scientists now understand the biological reasons behind the acts that Dr Levick considered "depraved".
The Natural History Museum has published his unedited papers.

Mr Levick, an avid biologist, was the medical officer on Captain Scott's ill-fated Terra Nova expedition to the South Pole in 1910. He was a pioneer in the study of penguins and was the first person to stay for an entire breeding season with a colony on Cape Adare.

He recorded many details of the lives of adelie penguins, but some of their activities were just too much for the Edwardian sensibilities of the good doctor.

He was shocked by what he described as the "depraved" sexual acts of "hooligan" males who were mating with dead females. So distressed was he that he recorded the "perverted" activities in Greek in his notebook.

Graphic account

  On his return to Britain, Mr Levick attempted to publish a paper entitled "the natural history of the adelie penguin", but according to Douglas Russell, curator of eggs and nests at the Natural History Museum, it was too much for the times.

"He submitted this extraordinary and graphic account of sexual behaviour of the adelie penguins, which the academic world of the post-Edwardian era found a little too difficult to publish," Mr Russell said.

Pages from Dr Levick's notebook with some sections coded in Greek

 

The sexual behaviour section was not included in the official paper, but the then keeper of zoology at the museum, Sidney Harmer, decided that 100 copies of the graphic account should be circulated to a select group of scientists.

Mr Russell said they simply did not have the scientific knowledge at that time to explain Mr Levick's accounts of what he termed necrophilia.

"What is happening there is not in any way analogous to necrophilia in the human context," Mr Russell said. "It is the males seeing the positioning that is causing them to have a sexual reaction.
"They are not distinguishing between live females who are awaiting congress in the colony, and dead penguins from the previous year which just happen to be in the same position."

Sexual coercion

  Only two of the original 100 copies of Mr Levick's account survive. Mr Russell and colleagues have now published a re-interpretation of Mr Levick's findings in the journal Polar Record.
Mr Russell described how he had discovered one of the copies by accident.

"I just happened to be going through the file on George Murray Levick when I shifted some papers and found underneath them this extraordinary paper which was headed 'the sexual habits of the adelie penguin, not for publication' in large black type.

"It's just full of accounts of sexual coercion, sexual and physical abuse of chicks, non-procreative sex, and finishes with an account of what he considers homosexual behavior, and it was fascinating."
The report and Mr Levick's handwritten notes are now on display at the Natural History Museum for the first time. Mr Russell believes they show a man who struggled to understand penguins as they really are.

"He's just completely shocked. He, to a certain extent, falls into the same trap as an awful lot of people in seeing penguins as bipedal birds and seeing them as little people. They're not. They are birds and should be interpreted as such."

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Antarctic moss lives on ancient penguin poo

5 July 2012
By Victoria Gill
 Science reporter, BBC Nature


Moss plants that survive the freezing conditions of Antarctica have an unusual food source, scientists say.

The vibrant green plants take nutrients from the poo left behind by penguins that lived in the same area thousands of years ago.

Scientists made their discovery whilst testing the plants to find out how they manage to survive in the icy landscape.

The findings were presented at the Society for Experimental Biology's annual meeting in Salzburg, Austria.

Prof Sharon Robinson, from the University of Wollongong in Australia, has been studying Antarctica's plants for 16 years.

She explained that she was interested in where the plants get their nutrients, because the Antarctic soil on which they grow is so poor.

"Plants need water, sunlight and nutrients; there's plenty of sunlight in the summer and as long as the ice melts there's water," she told BBC Nature.

"But the soil is basically sand and gravel."

To find out where the plants were getting the food they needed to grow, Prof Robinson and her team used a technique that allowed them to see all of the chemicals that made up a moss plant.

This "chemical signature" revealed nitrogen that had passed through a marine predator.

"Nitrogen that's gone through algae, krill and fish and then penguins has a characteristic 'seabird signature'," Prof Robinson told BBC Nature.

Since no penguins live on the elevated lakeside site in East Antarctica, the researchers had to work out where the mysterious seabird poo came from.

They realised that their moss beds were growing on the site of an ancient penguin colony.

"Between 3,000 and 8,000 years ago, on the site where the moss is now growing, there used to be [Adelie] penguins," said Prof Robinson.

"There's fossil evidence to support that, and the little pebbles that the penguins use to make their nests are actually still there.

"The other thing that's still there is the penguin poo.

 Six different species of moss live on the islands of East Antarctica studied by the scientists
"And because Antarctica is so cold, those nutrients have just stayed frozen in the soil; they're now feeding this moss."

Prof Robinson said that the hardy plants, which grow just 2-3mm per year, create "luxuriant green beds" that are home to some of the insects and other miniature creatures that manage to live in this frozen desert.

Prof Robinson hopes to learn exactly how they adapt to this extreme environment.

The mosses are able to "freeze-dry" in order to survive the winter and produce sunscreen compounds to protect themselves from UV rays.

"It's amazing that the plants can do [these things], but it's also interesting to know which compounds they use," said Prof Robinson.

Learning the molecular mechanisms behind plants' abilities to dry out but remain viable could help researchers to develop ways to store food or even medicines for long periods.

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Newly Discovered Dinosaur Implies Greater Prevalence of Feathers in Dinos Not Related to Birds

Caption: Skeleton of Sciurumimus as found on a limestone slab. (Credit: H. Tischlinger\Jura Museum Eichstatt)

Newly Discovered Dinosaur Implies Greater Prevalence of Feathers; Megalosaur Fossil Represents First Feathered Dinosaur Not Closely Related to Birds

ScienceDaily (July 2, 2012) — A new species of feathered dinosaur discovered in southern Germany is further changing the perception of how predatory dinosaurs looked. The fossil of Sciurumimus albersdoerferi,which lived about 150 million years ago, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds.

The fossil is described in a paper published in the Proceedings of the National Academy of Sciences on July 2.

"This is a surprising find from the cradle of feathered dinosaur work, the very formation where the first feathered dinosaur Archaeopteryx was collected over 150 years ago," said Mark Norell, chair of the Division of Palaeontology at the American Museum of Natural History and an author on the new paper along with researchers from Bayerische Staatssammlung für Paläontologie und Geologie and the Ludwig Maximilians University.

Theropods are bipedal, mostly carnivorous dinosaurs. In recent years, scientists have discovered that many extinct theropods had feathers. But this feathering has only been found in theropods that are classified as coelurosaurs, a diverse group including animals likeT. rexand birds. Sciurumimus -- identified as a megalosaur, nota coelurosaur -- is the first exception to this rule. The new species also sits deep within the evolutionary tree of theropods, much more so than coelurosaurs, meaning that the species that stem from Sciurumimus are likely to have similar characteristics.

"All of the feathered predatory dinosaurs known so far represent close relatives of birds," said palaeontologist Oliver Rauhut, of the Bayerische Staatssammlung für Paläontologie und Geologie. "Sciurumimus is much more basal within the dinosaur family tree and thus indicates that all predatory dinosaurs had feathers."

The fossil, which is of a baby Sciurumimus, was found in the limestones of northern Bavaria and preserves remains of a filamentous plumage, indicating that the whole body was covered with feathers. The genus name ofSciurumimus albersdoerferirefers to the scientific name of the tree squirrels,Sciurus, and means "squirrel-mimic"-referring to the especially bushy tail of the animal. The species name honours the private collector who made the specimen available for scientific study.
"Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton," said co-author Helmut Tischlinger, from the Jura Museum Eichstatt.

Sciurumimusis not only remarkable for its feathers. The skeleton, which represents the most complete predatory dinosaur ever found in Europe, allows a rare glimpse at a young dinosaur. Apart from other known juvenile features, such as large eyes, the new find also confirmed other hypotheses.

"It has been suggested for some time that the lifestyle of predatory dinosaurs changed considerably during their growth," Rauhut said. "Sciurumimus shows a remarkable difference to adult megalosaurs in the dentition, which clearly indicates that it had a different diet."

Adult megalosaurs reached about 20 feet in length and often weighed more than a ton. They were active predators, which probably also hunted other large dinosaurs. The juvenile specimen of Sciurumimus, which was only about 28 inches in length, probably hunted insects and other small prey, as evidenced by the slender, pointed teeth in the tip of the jaws.

"Everything we find these days shows just how deep in the family tree many characteristics of modern birds go, and just how bird-like these animals were," Norell said. "At this point it will surprise no one if feather like structures were present in the ancestors of all dinosaurs.

The study was financed by the Volkswagen Foundation and the American Museum of Natural History.

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Story Source:

The above story is reprinted from materials provided by American Museum of Natural History.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Oliver W. M. Rauhut, Christian Foth, Helmut Tischlinger, and Mark A. Norell. Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany. Proceedings of the National Academy of Sciences, July 2, 2012 DOI: 10.1073/pnas.1203238109

American Museum of Natural History (2012, July 2). Newly discovered dinosaur implies greater prevalence of feathers; Megalosaur fossil represents first feathered dinosaur not closely related to birds. ScienceDaily. Retrieved July 3, 2012, from ­http://www.sciencedaily.com­ /releases/2012/07/120702210225.htm