Toxins as a defense strategy are well documented in the reptile and insect worlds. However, this New York Times article discusses the many instances where mammals have evolved a chemical strategy of their own. Take for instance the African crested rat. It is big and sports a flamboyant coat of black and white fur. It is also poisonous. This giant rat takes advantage of a convenient local resource for its chemical arsenal: the Acokanthera tree. By chewing the bark of the tree, the African crested rat builds up a potent chemical in its system that is toxic to predators. Moreover, the crested rat wants to be seen and its fur coat, visible even in low light, is a warning to predators. A video clip from Is That Skunk? is featured in the article. Watch the full episode of Is That Skunk? online.
Analyzing the mitochondrial DNA of horses from all over the world, scientists are developing a clearer picture not only as to their history, but also the history of human domestication of horses. Mitochondrial DNA is a sort of clock in which mutational changes can be traced back in time. What horse DNA reveals is that modern horses evolved from a common ancestor between 130,000 and 160,000 years ago. However, around 10,000 years ago, 18 separate mitochondrial DNA lineages emerged. Scientists believe this relatively sudden branching indicates that horses were being domesticated by humans in separate groups in different regions of Asia and Europe.
Read more at Discovery.
Because owners of exotic pets, such as python snakes, often discard them into the wild, Florida has a big problem. In the areas where these former pet Burmese pythons have established themselves, they are killing small mammals to the point of local extinction. According to the researchers, “observations of raccoons have crashed by 99.3 per cent, opossums by 98.9 per cent and bobcats by 87.5 per cent. Rabbits have vanished completely.” It is believed that because pythons are a recently introduced species, many animals in the areas affected, including predators, have not developed strategies to avoid them. The federal government has recently banned the importation of Burmese pythons, but that measure may be too late for some locations in Florida.
Read more at New Scientist.
Watch the full episode of PBS Nature’s Invasion of the Pythons which addresses the issue of pythons in the Everglades.
The technology of genetic sequencing has become cheaper and faster. This has enabled paleontologists to analyze more ancient human remains, more quickly, in their quest for genetic markers that shed light on our ancestry. Scientists now believe that modern humans and their Neanderthal cousins interbred and that non-African human DNA is about 2.5% Neanderthal. Even more striking, after analyzing a pinky finger from the 40,000-year-old human remains in a Siberian cave, scientists conclude that a third group, which they call the Denisovans, also contributed to the DNA of modern humans. As much as 5% of the genome of people from Oceana (South Pacific) contains Denisovan DNA.
Read more at New York Times.
NASA has weighed in again on the continuing controversy over climate change. A new study looked at the solar activity between 2005 and 2010. Even though solar activity during that period was lower than usual, the earth warmed nevertheless.
Read more at Red Orbit.
They may just be young teenagers, but the Shank brothers, ages 9 to 16, have already made an impressive contribution to the study of nature. They waited over a week to photograph a rare albino ruby-throated hummingbird. The brothers utilized several cameras and took numerous photographs of the bird in August 2011. Of course, their inspiration probably runs in the family. Their father, Kevin Shank, publishes the Nature Friend Magazine in Virginia.
See images at Global Animal.
The “Cross River Gorilla” is the world’s rarest, with a population of only about 300. In an effort to determine how sustainable its habitat is in west central Africa, between Nigeria and Cameroon, conservationists resorted to high resolution satellite imaging of the areas the gorilla is known to frequent. The scientists examined satellite images pixel by pixel and also relied on ordinary survey work to estimate the amount and quality of the gorillas’ remaining habitat. The good news is that the situation is better than expected. Assuming that vital corridors between mating areas can be kept open and protected, there is ample suitable habitat for these gorillas at the present time.
Read more at Red Orbit.
Research into epilepsy has allowed scientists some insight into a region of the brain that appears to be hard-wired to react to images of animals, and only animals. The amygdala is the part of the human brain that is thought to control emotions and basic responses, such as fight or flight. Epilepsy patients were being treated with electrodes implanted in their brains. When they were showed a group of pictures, a small number of neurons in a specific portion of the right amygdala responded to images of animals. The remainder of the patients’ brains showed no reaction. The development has led to speculation about the evolutionary roots of the amygdala and the importance of animals in the lives of our ancestors.
Read more at Scientific American.
An article in Scientific American makes available a slide-show of fish that have been x-ray photographed. The slide-show is based upon an exhibit at the Smithsonian National Museum of Natural History. “X-ray Vision: Fish Inside-Out,” will be on display until August, 2012.
Read more at Scientific American.
From 1998 to 2005, international cooperation and tough enforcement led to an encouraging fall in the production and sale of ivory products in Egypt. Unfortunately, recent unrest as well as new demand from abroad may be the undoing of elephants. The first part of this two-punch assault derives from civil unrest, which has markedly decreased enforcement of Egypt’s ivory protection laws. The second is from increased demand. A marked uptick in illegal ivory sales has been detected in major cities in Egypt. Demand from Chinese buyers, especially, is driving a new surge of ivory sales and its concomitant encouragement of illegal elephant pouching. According to the article on TRAFFIC’s website, “One ivory vendor told the investigators that Chinese buyers would sometimes spend USD 50,000 on ivory during one bargaining session.”
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
In the rivers and caves of Sierra de El Abra, Mexico, cave fish that never see the light of day have evolved without eyes or pigmentation. These fish are believed to “have had at least five separate evolutionary origins from these two ancestral stocks.” What is puzzling, however, is why the sightless cave fish maintain their sightlessness despite the fact that interbreeding with normal cousin surface fish is common. According to scientists at NYU’s Cave Biology Group, cave fish maintain their genetic predisposition for sightlessness, despite interbreeding, because there must exist some adaptive advantage to remaining sightless in a dark world.
Read more at Science Daily.
The forests of southeast Germany lost their wolf population to human predation. Ten years ago, a pair of wolves from the Sudeten Mountain region of Poland traveled to this region. Since then, the fertile couple has been singly responsible for re-populating the German forests in this region. Named One-eye and Sunny, the pair had been radio-tagged years ago, so that their movements have been carefully watched by scientists. The wolf is a protected species in Germany, and it is believed that the large populations of deer in the area could support hundreds of wolf packs.
Read more on Global Animal.
A 33,000 year old wolf fossil from Siberia is lending support to the theory that the domestication of wolves took place over a long period of time and occurred at multiple locations simultaneously. In this case, the fossil indicates a wolf that was in the early stages of domestication, which is typically marked by a shortening of the snout and crowding of teeth. A similar fossil, found in Belgium, was in approximately the same stage of semi-domestication. Since these particular individuals were unlikely to have survived the last glacial event, it underscores the recurrent nature of human/wolf domestication.
Read more at Red Orbit.
A recent publication in the Royal Society Biology Letters announces the discovery of iridescent moles. With the exception of the eyes of nocturnal animals, no other mammals display iridescence. But this poses a question: why would iridescence occur in animals such as moles, which are blind? It is true that moles evolved from sighted ancestors, but that does not explain the benefit to maintaining their sparkling coats. On the other hand, since iridescence may simply be the byproduct of the geometrical structure of the layered fur, it might not play a significant evolutionary role at all.
Read more at Yahoo.
Utilizing DNA analysis from some 600 horses representing several regions and continents, scientists believe they have determined the original horse that conferred special speed on its descendants. To obtain the proper DNA, the scientists had to extract it not only from live horses, but also from the bones of dead thoroughbreds, and even “from 40 donkeys and two zebras.” The founder speed horse was a mare that likely lived in Britain some 300 years ago. In modern times, a variant of the “speed gene” developed, and can be traced back to two well-known champions, Nearctic and his son, Northern Dancer.
Read more at University College of Dublin.
In Scientific American, a controversial new theory posits that bonobos became a calmer, more domesticated version of chimps because their environment permitted a longer maturation period. According to Brian Hare of Duke University, the region south of the Congo region is where bonobos ancestors lived – chimpanzee ancestors lived on the north side of the river. Because the bonobos faced fewer threats from predators than did chimpanzees, Hare believes that they evolved more domesticated features and behaviors. Indeed, bonobos are considerably less aggressive than chimps, are smaller, mature more slowly and have shorter fangs. Hare also points out that domestication of dogs by humans produced similar traits. Other bonobo experts do not buy Hare’s theory, however, and in fact proving it may be very difficult.
A study carried out by the Andrew Higginson of Bristol University’s School of Biological Sciences reveals that the amount of fat different animals carry is a function of the optimal ratio of fat to muscle for that particular animal’s behavior. For example, more fat would allow the animal to avoid starvation in difficult times, but also would cause it to become slower and more vulnerable to predators. The study’s author summed up the findings this way: “Bats fly and so have high costs of carrying extra weight, whilst carnivores spend much of their time resting and so will use less energy than busy scurrying rodents.” Unfortunately, none of this sheds much light on the human struggle with weight.
Read more at Discovery.
At the Lawrence Berkeley National Laboratory scientists are using a cryo-electron microscope to take photographs of individual proteins in 3-D. The machine, which costs $1.5 million, operates at the temperature of liquid nitrogen. This low temperature allows soft matter, such as protein, to be imaged in 3-D for the first time. Multiple images of the protein must be taken in order to create the 3-D effect.
Read more at Berkeley Lab.
Using sophisticated electron microscope techniques, scientists believe they have discovered additional proof that Archaeopteryx, the much photographed winged dinosaur, had black feathers. Why is that important? Apparently, in modern birds, pigmented structures in the feathers not only provide color but actually give the wing the additional strength it needs for flight. These pigmented cells, called melanosomes, could be seen in significant number in Archaeopteryx’s fossilized feathers using the new microscopy technique. While this does not prove that the creature could fly, it adds to the ever growing body of proof that it could.
Read more at the Daily Mail.
Known as the Kwamalasamutu expedition, researchers looking for new species of animals near Kwamalasamutu, Suriname, South America, seem to have hit the jackpot. The new species include many new fish, frogs and insects. The links below are a treasure trove of new pictures and videos about the finds.
Read more at Red Orbit.
http://www.pbs.org/wnet/nature/wp-admin/edit.php
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
The Australian Research Council’s Centre of Excellence for Coral Reef Studies has announced that it conducted research on the increased levels of CO2 in ocean water and its effect on fish. The results indicate that increased CO2 levels disrupt the neurochemistry of fish brains, which causes significant interference with their behavior and sensory abilities. Specifically, fish show impaired ability to hear and are less able to evade predators when CO2 levels are elevated. Worse, the scientists think that the interference in systemic and physically affects the entire fish brain.
Read more at Physorg.com.
Hidden in the New Guinea forests is a frog so small that it appears more like an insect than a vertebrate. The new species, Paedophryne amanuensis, is approximately a quarter of an inch long. It eats, not surprisingly, very small insects. The frogs hide in moist leaf litter on the forest floor. It is not yet known which predators feed on the tiny frogs, but it is suspected that they are prey for scorpions.
Read more at bbc.
An article in Scientific American discusses the possible links between head crests and mutual sexual selection in dinosaurs and pterosaurs. The size and variety of the crests seem to indicate that they were sported by both males and females, and part of their purpose may have been to select the most fit individuals for mating. The authors further suggest the possibility that the evolution of feathers displaced the role of crests as a vehicle for mutual sexual selection. Modern birds, of course, rely upon their excellent color perception to assess potential mates based upon their colorful plumage. Dinosaurs, which also are believed to have had excellent color vision, may have evolved feathers for that same reason.
Read more at Scientific American.
For 165 years, slides and fossils collected by paleontologists, including Charles Darwin himself, had been languishing in a wooden cabinet in the British Geographical Survey Headquarters in Britain. Now, a serendipitous re-discovery of the cache is proving to be an exciting surprise for scientists. One scientist said that the first slide he looked at was from Darwin’s famous expedition to the Galapagos Islands aboard the Beagle and signed by Darwin himself. The entire collection has been photographed and is now online.
Read more at RedOrbit.
When a boa constrictor has an animal in its grasp it needs a foolproof way to know when it’s dead. Scientists have now discovered that boas feel the heartbeat of their prey and squeeze until it fades away. Even when experimenters used a fake beating heart in dead prey, the snakes continued to squeeze well past what is normal. Moreover, the skill appears to be innate. It may seem to be ‘overkill’ to have developed this system for mammals, for which a crushing squeeze quickly leads to death. However, the experimenters surmise that because reptiles, which also serve as boa dinner, have such slow heartbeats and can withstand considerable crushing, there was an evolutionary advantage for boas in measuring the heartbeat of all prey.
Read more at Live Science.
Airliners are not alone in wanting to optimize fuel efficiency. It appears that the wandering albatross, as well as other birds, are taking full advantage of the increase in wind speeds in the Southern Ocean. Because climate change seems to increase wind speeds over oceans, birds are getting to their foraging and nesting destination faster than usual. That means more successful breeding and healthier animals. Scientists warn, however, that this may be a short term advantage because much higher winds in the wrong direction may one day become a distinct disadvantage for the birds.
Read more at Audubon Magazine.
For the 54th consecutive winter, a team of specialists moves into Isle Royale, a frozen island wilderness surrounded by Lake Superior. As they do every year, the team documents the relationship between moose and the wolves that prey on them. In this New York Times article, the author describes the exceptionally harsh winter conditions that face the inhabitants of the island. Temperatures can get so low that trees can split open in the night. A chart showing the changing interconnection between moose and wolf populations is an interesting example of natural balance.
A new species of lemur has been identified in Madagascar. Microcebus gerpi is about the size of a hamster and lives in the rainforests of eastern Madagascar. It has been apparently hiding in plain sight among other lemur species. Unfortunately, the lowland regions that compromise this lemur’s natural environment are not protected and the threat of human incursion will put pressure on the lemur’s survival.
Read more at Discovery.
The surprising answer seems to be: not long at all. In an experiment carried out by scientists at the University of Minnesota, single cell yeast were grown under conditions that favored those yeast cells that fell to the bottom of the flask. In just a few weeks, more and more yeast cells were ending up at the bottom on the flask, indicating that they were adapting to the experiment. When the surviving yeast cells were examined under a microscope it was discovered that the yeast had transformed itself from single cell organisms to multi-cell organism that grew together in a snowflake like form. One scientist, Richard Lensky of Michigan State University, commented on the results: “It shows that a major transition in evolution — going from unicellular to multicellular life forms — might not be as hard to achieve as most biologists have long thought.”
Read more at New York Times.
Australian male bower birds construct elaborate bowers from twigs, bones and rocks. Because the bower is constructed in a tunnel-like manner and it and the male are inspected by interested females from one end of the tunnel, optical illusion plays an important role. If done properly, the male bower’s legerdemain will make him appear larger and more virile than he might otherwise be. In addition, the more interesting the illusion, the more time the female will spend observing it, which in turn increases the chances of mating. Not surprisingly, it was determined that males which produced the best illusions more often than not got the girl.
Read more at Live Science.
An “absent minded professor” from San Francisco State University may have stumbled upon the cause of the calamitous colony collapse disorder that has threatened bee colonies in the United States and elsewhere. Biology professor John Hafernik had collected dead bees in a vial and intended to investigate their demise when he absent-mindedly left the vial on his desk for a period of time. When he finally got around to re-examining them, he saw that the bee bodies were covered with pupae from a parasitic fly. Apparently, the fly lays eggs on the bodies of bees, which turns the bees into fly nurseries, killing the host in the process. Now researchers have found evidence of this parasitic fly in almost 80% of the bees hives in California’s Bay area.
Read more at nature.com. Watch the full PBS Nature film, Silence of the Bees.
Operation Migration is an effort by a private/governmental organization to reestablish a “flyway” for whooping cranes between Wisconsin and Florida. This migratory flyway has not been used by the cranes for since the 1800’s, when the population of cranes that used it died off. With only one other flock of cranes left (which use a different flyway) the operation is intended to ensure that at least one flock of the remaining Whooping Cranes will survive. Using the principle of imprinting, humans dressed as whooping cranes are the first thing young cranes see when hatch. The cranes then follow the human crane parents, who use a small plane that also resembles a crane. The birds then follow the plane along the intended flyway, thus teaching them a new route for migration. Unfortunately, the operation was temporarily suspended when it was revealed that the pilot lacked a commercial pilot’s license, which is necessary because he was paid by the group.
Read more at Global Animal.
Several new species of marine creatures discovered miles beneath the sea in the Caribbean are stranger than easily imagined. The fact that the creatures thrive in temperatures that are multiples of the boiling point of water is difficult to explain or comprehend. However, this gallery of photos is guaranteed to impress.
More at Mongabay.
Teams of scientists from MIT, Washington State University and the University of Iowa, have been exploring a theory that ties the Permian extinction event to volcanism in the Siberian Traps — a highly volcanic region of Siberia. The Permian extinction was earth’s most severe, wiping out some 90% of marine species and some 70% of terrestrial species. So far, the results indicate that huge amounts of sulfur, chlorine and fluorine (all capable of creating destructive acids) were released toward the end of the Permian extinction event. Whether this association will prove to be a causal factor in the extinctions awaits further research.
Read more at msnbc.
Anyone with a lawn knows that insects can eat plant roots. However, scientists in Brazil have found a plant, Philcoxia minensis, that gets its nutrients by attacking worms below the ground. In this case, most of the plant’s leaves grow beneath the surface where they attach themselves to small worms. Scientists were led to the plant’s unusual feeding technique when they questioned why evolution would favor subterranean leaves that could not conduct photosynthesis. They soon realized that the leaves had adapted to a different purpose – drawing nutrients from worms.
Read more at Red Orbit.
A species of tortoise, C. elephantopus, from the Galapagos Islands had been considered extinct since the 19th century. However, bones collected from tortoise remains and kept in museums were recently analyzed for DNA. The result has surprised scientists. The DNA of C. elephantopus has been found in the bones of these other tortoises. That means they are hybrids and must have bred with C. elephantopus over the past 15 years. Given the long lifespan of these tortoises, up to 100 years, there is hope that future expeditions can locate a surviving C. elephantopus individual.
Read more at Discovery.
Tourists enjoy close encounters with sharks, as long as they are not too close. In the Philippines, it has become common practice to throw food to whale sharks so that they come to the water’s surface and impress the tourists. In an article in Global Animal, the author explains why this practice may be far more threatening to the sharks than to the tourists. Among other reasons, habituating sharks to free meals makes them more likely to intentionally interact with large boats and the results can be deadly for the sharks.
The effect of rising temperatures on lizards has been a source of concern for some time. However, a recent study from scientists at the University of Sydney suggests that warmer incubation environments seem to result in smarter, more adaptable lizards. Compared with lizards raised in normal temperatures, the lizards which were raised in higher temperature environments had an enhanced ability to escape predators and to learn from experience. However, the scientists do not suggest that this enhanced cognitive functioning, derived from warmer incubation, can outpace the damage done to lizards from overall higher global temperatures.
Read more at Science.
A disease called epizootic hemorrhagic disease, or EHD, has killed an unusually large number of white-tailed deer this year in Montana. The disease is spread by biting insects – midges — and an animal can succumb to the resulting internal bleeding in just a few days. The outbreak is blamed on a warmer than average fall season, which caused the transmitting insects to thrive for longer than usual, and a harsh winter, which culled a large number of deer. While deer are losers, there are also winners. Cottonwood trees, long decimated by huge deer populations, now will most likely thrive with a greatly reduced deer population.
Read more at abc news.
Around 100 million years ago, an area stretching from around Boulder, Colorado to central New Mexico formed a wet coastal plain ideal for dinosaurs and crocodiles. So many dinosaur footprint fossils have been recovered from this area, that it has been dubbed a dinosaur freeway. The dinosaurs using this route traveled in herds and were probably migrating to new food sources.
Read more at msnbc.
The Mekong River area of Southeast Asia is threatened by deforestation and other human incursions into its ecosystem. In what amounts to another ‘just in time discovery,’ 208 new species of animals have been studied and documented in the area. In nearby Myanmar, one of the species is new to modern science but well-known to local residents. It is a monkey that sports an Elvis-like hairdo. How many of these “new” species will survive into the next decade is an open question.
Read more, and see a slideshow at Huffington Post.
An experiment conducted with lab rats was designed to measure the level of empathy rats feel for each other. In the experiment, free rats were able to see their buddies entrapped in a cage area that had a door. The trapped rats vocalized a distress call which the free rats seemed to act upon. In an obvious effort to free a comrade, rats consistently made repeated efforts to open the door. Even when treats of chocolate were used to distract the good Samaritans, the free rats spent most of their time opening the door and even left some of the chocolate for the escapees to enjoy. Scientists interpret these results as evidence that rats get significant satisfaction from engaging in empathetic behavior.
Read more at Global Animal.
Swimming the English Channel is an impressive feat. But how about swimming from New York to Sydney, Australia and back? Using a tracking device, the Wildlife Conservation Society has monitored the progress of Jackson, a male elephant seal, over the course of about 11 months. During that time period, the prodigious swimmer covered some 18,000 miles. The tracking program helps marine biologists understand the migratory patterns of elephants seals, which in turn informs their selection of marine regions are in need of ecological protection.
Read more at Red Orbit.
Footprints that have become fossilized over millions of years are studied by paleontologists because they reveal how ancient animals traversed the earth. Recent evidence, however, sparked by a study of African lungfish suggests that some of these footprints were most likely made by the fins of fish that walked on the sea floor. Lungfish are members of the Sarcopterygian fishes, which are believed to be the ancestors of four-legged animals that walked first on sea beds and then on land. A scientific team from the University of Chicago has produced a video that demonstrates the lungfish behavior, and makes the mix-up between ‘finprints’ and footprints easier to understand.
Read more at Science News.
About 260 million years ago, evolution’s early experiments with mammal-like creatures produced a fearsome specimen. Called a varanopid pelycosaur, this sleek dinosaur-era animal had a huge jaw and physically resembled modern monitor lizards. Paleontologists believe that the creature was mammal-like, and although it was not a direct ancestor of today’s mammals, it represents one step along that road. The razor-sharp teeth of the creature suggest that it was a hypercarnivore – an animal that consumes at least 70% of its calories from meat. It became extinct some 35 million years ago, and it took another 35 million years for nature to produce the real ancestors of mammals.
Read more at Discovery.
In the forests of Panama and Costa Rica lives a truly brainy spider. The creature, Anapisona simoni, weighs only 5 micrograms but spins complex webs – an endeavor that requires significant brain power. In order to pack that much brain power into such a tiny body, evolution has come up with an interesting solution. The spider’s ‘brains’ have migrated to other parts of its body in addition to its head. Indeed, some 80% of the spider’s head and thorax are made of neural cells, and these cells have even migrated to the spider’s legs.
Read more at New Scientist.
Humans differ from their ape cousins in many ways, not the least of which is the marked absence of a thick coat of body hair. However, we have not really lost the follicles. In fact, the follicle density of our bodies is roughly the same as other primates, but instead of thick hair we sprout mostly thin peach-fuzz. In a study published in Biology Letters, the authors believe that we retained our diminished fur coat because it remains useful. In an experiment, volunteers who shaved their arms were much less able to detect creepy-crawlies than those who had not shaved. Thus, our body hair may have gotten an evolutionary nod because it provides an excellent early warning system for bedbugs and other parasites.
Read more at Scientific American.
An insect’s exoskeleton, or cuticle, is a truly remarkable construct. Made of layers of chitin and protein, in a laminate that resembles plywood, the material is extremely light and yet extraordinarily strong, flexible and durable. Now, using the blueprint for insect cuticles, researchers at the Wyss Institute for Biologically Inspired Engineering at Harvard University have developed a material called “shrilik” that may someday replace plastics in many applications. The scientists are especially hopeful that the material will be useful in medical procedures where light-weight and resilient materials are needed for sutures and scaffolds for tissue regeneration. Even better, shrilik comes with a bonus – it’s biodegradable and inexpensive to manufacture.
Read more at Red Orbit.
The light that reflects off the petals of a buttercup flower appears eerily bright and intensely yellow. Analyzing the structural properties of a buttercup’s petals, scientists have uncovered its trick. It turns out that the flower petals have not one but two different surfaces that are separated from each other, causing light to be reflected mirror-like in different directions. A pigment in the petal absorbs the blue light waves, and since the remaining light is reflected through this pigment two times, from one surface to another before being reflected outward, the yellow color that results from the absence of blue is intensified. Of course, buttercups aren’t designed for our pleasure. The light that they reflect includes ultra-violet light, which is readily detected by bees.
Read more at Live Science.
An article in Wildlife News claims that ranching industry supporters, who favor reducing wolf populations in the west by hunting, are using fraudulent photographs to gain political favor. According to the article, photographs of large packs of wolves have been deliberately misidentified to suggest that they live near populated areas in the west, when in fact they are photos of wolves taken in isolated terrain in Canada. In another alleged trick, photographs of wolves that have been shot are manipulated so that the animals appear to be much larger than they are. This, supposedly, not only enlarges the egos of the hunters, but adds a little extra fright for people who are already afraid of wolves.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
Ecologist and bear biologist Chris Morgan shares his thoughts on a recent story discussing the increase in polar bears looking to their own kind as a food source:
I’ve been lucky enough to guide several polar bear viewing expeditions to Svalbard in the European high arctic. It is a wildly isolated and beautiful place. The amazing polar bear shots that Jenny Ross captured with her camera jolt us into thinking about the many hidden implications of climate change. So often we’re drawn to the big picture data, or the sweeping effects that our planet is undergoing – and rightly so. But I also like to dwell on the stories that bring climate change to life, through the eyes of individual animals and people. Each and every polar bear is facing increased every-day stress as a result of our warming planet. One year I saw a female and cubs on a chunk of ice the size of perhaps two football fields. It was the last ice of the season in a west coast inlet of Svalbard, and she was going to float it until it was gone.
Bottom line: polar bears need ice. And there is one reason for that – their prey need ice. Polar bears feed almost exclusively on seals, and those seals are what scientists call pagophilic (”ice-loving”). As the world’s frozen seas shrink, so do opportunities for polar bears to hunt these seals and make a living from a habitat that gets smaller every year. Some of them are forced to take extreme measures – in this case cannibalism. In 2006 I found the remains of a bear in Svalbard that could well have been the result of similar cannibalism (see picture) by desperate bears.
Polar bears elsewhere face similar pressures. Their future was never far from my mind when we filmed polar bears for Bears of the Last Frontier in northern Alaska. The Southern Beaufort Sea population is looking at a questionable future – sea ice will decline there by 6% per decade over the next 45 years. We stand to lose two thirds of the world’s polar bears by the year 2050 due to the effects of climate change. That’s 16,000 bears in 40 years, or an average of more than one bear every day. Although difficult when it comes to the future of the polar bear, I like to dwell on the side of optimism. This century’s polar bears will persist for longest in the high arctic archipelago of Canada and northern Greenland – a high latitude refuge for these super-specialists. They will exist in much smaller numbers than they do today, but my hope is that they will provide a constant reminder – as well as a beacon of hope – to do right by our environment, and ultimately to do right by ourselves.
Pictured: Chris Morgan with a polar bear skull in Svalbard. (Credit: Ellie Van Os)
Stories of animals fleeing an area well before an earthquake strikes have fascinated scientists and laymen alike. Rachel Grant, a biologist, was studying toad populations in a lake in L’Aquila, Italy. Just before the 2009 earthquake there, Grant noticed that the entire population of toads left their lake suddenly, even though there had been no discernible disruptions. She published a paper on the phenomenon. Meanwhile, NASA scientists had been studying recent measurements of the chemical changes that rocks undergo due to geothermal pressure just before an earthquake occurs. One of those scientists, Friedemann Freund, came across Grant’s paper describing the strange toad exodus. Now collaborating, the pair has theorized that pre-earthquake chemicals from molten rocks below the lake had suffused into the L’Aquila lake water and had been quickly detected by the highly sensitive toads and other amphibians. Whether the discovery will have earthquake predictive utility remains to be seen.
Read more at The Telegraph.
The ever-surprising intelligence of ravens, crows and magpies (Watch the full A Murder of Crows PBS NATURE episode) has a new chapter. Researchers now believe that ravens use their wings and beaks to communicate— similar to how we use our hands and arms. The researchers observed that the communication often took place as part of the mating ritual, with one partner presenting an object for the other to inspect, which often led to that partner looking at the object. Researchers believe this is the first observed instance of non-primate communication by gestures.
Read more at Live Science.
An encouraging surge in wildlife populations in Uganda’s national parks has been attributed to the reduction of hostilities by rebel forces in that country. The armed conflict between the rebels and government forces meant that for years poaching could not be enforced inside the national parks. Now, with a reduction in hostilities, poaching enforcement has led to a wildlife comeback. According to Global Animal, zebra, giraffe, impala and waterbuck have increased three-fold in the past decade.
Jaguars are large cats second in size only to lions and tigers. They are seen, if at all, in the jungles of Central and South America. Recently, however, there have been a handful of jaguar sightings in southern Arizona. Apparently, the animals have migrated north from Central America into Mexico and are crossing over the Arizona border. In an article in the New York Times, a professional guide who takes tourists to see mountain lions in Arizona described his surprising and hair-raising close encounter with a wild jaguar.
Genetic diversity is usually a necessary element to keep a species healthy and thriving within a particular environment. Normally, excessive inbreeding causes mutations and disease in a colony of insects leading to its eventual collapse. However, bedbugs prove to be an exception to the rule. According to the American Society of Tropical Medicine and Hygiene, bedbugs in urban centers have been able to use their tolerance for inbreeding to explode their populations. Since a single egg-laying female can produce many progeny, it would be a great advantage if those siblings could mate and produce an ever-growing colony of inbred bedbugs. In urban apartments in the United States, that is exactly the mechanism that is driving the recent bedbug infestations that can spread throughout an entire building. And, it should not come as any surprise that cockroaches enjoy the same inbreeding resistance.
For years, scientists have been looking for a way to clone a woolly mammoth. They have been tantalizingly close — recovered remains of the animals from the Arctic have yielded excellently preserved specimens. Still, the DNA of the preserved specimens has been incomplete, up until now. Enter global warming. The disappearance of ice in Siberia as a result of warmer temperatures there has led to the uncovering of new mammoth remains. Now, scientists have extracted organic material from the thigh bone of one of the new specimens that they believe contains intact DNA sufficient for cloning. The cloning will involve the use of an elephant egg which, after being denucleated, will have a mammoth cell nuclei inserted. If successful, the experiment will spawn the first mammoth to walk the earth in thousands of years.
Read more at Discovery.
If you are a fruit-eating bat, you might be able to out-compete your peers if you can sink your teeth into something harder than they can handle. The price, however, is a face which is, well, quite ugly. The Centurio senex bat is a member of the fruit-eating bat family. Scientists believe that in times of food scarcity, it evolved a skull and facial structure that is extremely wide and short, giving its jaws better leverage. In fact, although it clearly will win no beauty pageant, the evolved skull of this bat gives it a 20% stronger bite than its rivals.
Read more at BBC News.
Like all amphibians, Hellbenders are very sensitive to pollution and other changes in their ecosystem. These salamander-like creatures once thrived in the rivers of Missouri and Arkansas, but they have been in serious decline over the past few years with their numbers dropping to less than 10% of what was measured in a previous census. The St. Louis Zoo, however, has come to the rescue. Zoologists there have created streams and specially equipped rooms that provide ideal conditions for the Hellbenders to reproduce. This November, the zoologists were rewarded with the birth of 63 larvae that will hopefully mature and help repopulate the Hellbenders in the wild.
Read more at Discovery.
Cowbirds are infamous for their habit of laying eggs in the nests of other birds, expecting their chicks to be fed and cared for by their unwitting hosts. In fact, they often break open a few, but not all, of the host’s eggs to give their own offspring better odds of surviving. Here, the strategy is to leave enough host eggs so that the host parents do not completely abandon the nest. Mockingbirds have adapted to this predatory behavior by cowbirds with a peculiar strategy of their own. Rather than destroy the detected cowbird eggs, they ignore them. Why? It appears that leaving the cowbird eggs increases the likelihood that the next cowbird to visit the nest will destroy the previous cowbird’s eggs and leave at least some of the mockingbird eggs alone.
Read more at New Scientist.
Chris Funk is a biologist with Colorado State University’s Department of Biology. He and his team have carefully catalogued frogs in the Amazon basin, a region that includes parts of six different countries. What they found may be good news for conservationists. Twelve new species of tiny tree frogs were discovered in the expedition. In the past, many of the new species had been mistaken for closely related species. However, DNA analysis helped make the difficult distinctions. Extrapolating these results to other amphibians that also inhabit the same area, Funk believes that “as many as 1,900 new species could be unveiled.”
Read more at Colorado State University.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
Researchers from several countries have discovered the fossilized remains of some 80 whales. What makes the discovery so interesting is that they were found in the world’s most extreme dessert – the Atacama Desert in Chile. Several species of whales, as well as other ocean mammals, have been identified so far. The researchers must next determine the age of the fossils (present estimate is that they are around 8 million years old) and answer the question why so many whale fossils were collected in one place.
Read more at nature.com.
A researcher named Francesco Lacquaniti of the University of Rome has conducted an experiment to determine how humans and other mammals learn to walk. Although humans might think that they are unique in this area, it turns out that is not quite the truth. Using an electromyograph (EMG) to measure the use of muscles, Lacquaniti found that human newborns, as well as well as their four-legged newborn cousins, employed very similar muscle engagement and demonstrated essentially the same two phases of newborn walking development. They also had a similar four-phase progression of walking development into adulthood. Walking, it would seem, has a common evolutionary origin in the distant past.
Read more in New Scientist.
Last week, the American Museum of Natural History announced the discovery of several new species of bees. There are a total of 11 new species in the group, which includes four new species identified in New York City and its surrounds. One of the new species, Lasioglossum gotham, (yes, that’s gotham) apparently makes its living pollinating the diverse flowers found in the botanical gardens in New York City and its suburbs. What is most encouraging about the proliferation of bee species is that it may offset the well-publicized and still mysterious declines in bee populations elsewhere in the world.
Read more at Global Animal.
Counting snow leopards is not easy. These beautiful but reclusive cats prefer the most difficult and mountainous snow-covered terrain. So, in order to count them, researchers rely of inferred sightings, which include tracks, scat and even local residents’ accounts. Recent estimates of the snow leopard population in Central Asia were from 350 to 500, spread across several countries of the central Himalayas. However, after analyzing the genetic content of scat, the researchers found fewer than the expected number of snow leopards — the remaining genetic material was from different carnivores. Although this is disappointing news for the survival of the species, at least the genetic testing of scat in the future will probably yield much more useful information about genetic diversity of the remaining snow leopards.
Read more in Biology News. Learn more about snow leopards.
It may be an old joke that elephants are afraid of mice, but when it comes to bees, it’s no joke at all. Elephants avoid bees at all costs, and this natural fear has been put to good use by farmers in Kenya. In a clever exploitation of that fear, farmers are keeping elephants out of their crops, where they can eat prodigious amounts of food, by the use of bee hives. The hives are strategically situated and then connected by wires so that if the wires are disturbed by elephants, the hives vibrate and bees are quick to respond. Once the sound of buzzing bees is in the air, the elephants are in full retreat and even warn their comrades of the danger. And, since elephants’ memory is quite good, they don’t need to be reminded too many times. In fact, in the wild, elephants who are stung by bees from a particular tree will thereafter avoid that tree.
Thinking of dinosaurs, one imagines that a huge bone structure was vital to carrying the tremendous body bulk of these animals. It was, of course, but certain bones also served another purpose according to a recent study. Osteoderms are bones that are contained entirely within the skin. Two sauropod (plant eaters) specimens from Madagascar that contained half-football shaped osteoderms have led to a theory that the bones’ purpose was not structural but nutritional. The osteoderms contained high concentrations of phosphorus and calcium, necessary to the animals’ growth, egg laying, and the development of its structural bones. By storing these minerals in osteoderms, and re-absorbing them when feeding conditions were bad, the sauropods evolved something of a nutritional storehouse for ‘rainy days.’ Today, alligators and armadillos are among the modern animals that use osteoderms.
Read more at RedOrbit.
Why does a single species of frog come in such a varied assortment of colors and patterns? University of Montreal biologist Mathieu Chouteau has a theory based upon a recent experiment. Chouteau brought 3,600 plasticene painted models of frogs to the Amazon rainforest. The models varied in color and pattern. Some of them mimicked the two colonies of local imitator poison dart frogs. Each of the two colonies of frog has a distinct color and pattern. Local predators know that the poison dart frogs in their area are in fact poisonous and so they avoid attacking them. Using the two different sites, which were separated by only 10 kilometers, Chouteau deployed the model frogs to determine which ones would more likely be attacked by predators. The result at each site was that the model frogs that most resembled the local frogs were attacked the least, while the models that deviated the most from the locals color and pattern experienced the most attacks. Chouteau believes that the experiment shows that the same species of frog will evolve extremely local coloration and pattern changes in tandem with the local predators’ learning patterns.
Read more at Science Daily.
The much studied worm, C. elegans, was one of the first species to have its genome completely mapped. Now it has a new role—space traveler. As humans contemplate long-term trips to Mars and beyond, an unanswered question is how our DNA will hold up over prolonged periods to the many insults from outer space radiation. To find out, in 2006 scientists launched colonies of C. elegans into earth orbit as part of an automated experiment to measure how they would respond to long-term space exposure. So far the news is encouraging. After several years and multiple generations in space, C. elegans has prospered in earth orbit, which bodes well for the humans who might follow.
Read more at Space.com
Thus far, most robotic inventions have been modeled after creatures with internal skeletons. A team from Cambridge, Massachusetts has come up with a different idea. Rather than employing the weight and complexity of articulated joins and complex motors, they have modeled their robots on creatures without internal skeletons, such as squid and worms. The new “soft” robot uses plastic materials and pressurized gas to create a pneumatic approach to robotics. Although the inventors acknowledge that their robots cannot be used in every environment in which hard robots are used, the new breed might have the edge when flexibility is paramount.
Read more at nature.com. Watch the robot in action.
Invasive species transported around the world by international flights and cargo ships have received much attention over the years. In an interesting turnabout, studies show that some invasive species are disappearing from their new environment, even though they at first appeared to be successful. Take the Argentine ant, which found its way to New Zealand and seemed to be flourishing. The ant seemed to thrive on the climate and soil type, and its predilection for human habitats made it a most unwelcome pest. So after some 20 years of success, why is the Argentine ant beginning to disappear from New Zealand? Scientists believe that low genetic diversity is part of the problem, which makes sense if only a few individuals were in the pioneering group.
Read more at Live Science.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
It seems hawks can teach us a thing or two about flying. As reported first-hand by New York Times’ John Bishop, a new sport, “parahawking,” uses raptors as flight guides. The flights are conducted from a hill in Pokhara, a small Nepalese city within view of the Himalaya Mountains. The sport uses rehabilitated birds of prey that can no longer survive in the wild. Amazingly, the raptors have been taught to lead human paragliders (a small bribe of meat helps) to just the right updrafts for a scenic and no doubt unforgettable glide across some of the most beautiful terrain in the world. The operators hope that the parahawking school will help support efforts to save Nepal’s birds of prey from an anti-inflammatory drug, given to local cattle, that has been debilitating the raptor populations.
The pressing question of how cats manage to drink so neatly has been answered. It appears that cats don’t actually form a ladle with their tongues like dogs do. That would lead to a slobbery, messy chin – a situation no cat could tolerate. Instead, feline manners employ the principles of inertia. By dipping the tip of its tongue in the liquid at extremely high speed, too fast for the human eye to detect, and then retracting the tongue just as quickly, cats cause a column of the liquid to leave the surface directly above the tongue. Because the tongue is retracted so quickly, the column moves in the direction of the retracting tongue (inertia), where it momentarily defies gravity and neatly enters the cat’s mouth. The result: a refreshing drink and clean whiskers.
Read more at Global Animal.
An octopus or a squid can change their color within a fraction of a second. We know why they do it: to hide from predators. But why do they choose transparent camouflage for surface waters and red or black for the ocean bottom? Researchers now have an answer. It appears that a transparent camouflage makes any animal at surface level almost invisible. On the other hand, at the ocean bottom predators are known to use bio-fluorescence to search for prey. In that environment, a clear camouflage would make an octopus or squid light up. Instead, by turning dark red, the blue light of bio-fluorescence is absorbed and the creatures remain invisible.
Read more at Scientific American.
Every year, Olympus announces its Bioscape photography winners and honorable mentions. The photographs of microscopic life in the Olympus gallery for 2011 are a treat for the eyes.
Faster than the blink of a human eye, some bats can change the shape of their outer ears in order to fine tune their sonar reception. Bats send out ultra-sonic sounds which bounce off objects and return to their sensitive ears, thus mapping the space around them. Researchers studying the bats had to use high-speed, high-resolution equipment in order to detect the changes in the ear shape. The researchers believe that the high speed ear transformations are used in order for the bats to adapt to a specific environment, or to accomplish a particular sonar task.
Read more at ScienceDaily.
The New York Times reports that the confluence of efforts by many humane organizations is expected to put a stop to invasive chimpanzee medical research in the United States. Because they are so genetically similar to humans, chimps have been used for medical research that has successfully led to cures for several fatal human diseases. However, our closest cousins’ similarities to us are a double-edged sword. Many advocates for chimps and other primates have argued convincingly that subjecting near-humans to invasive biomedical research is immoral, despite the medical benefits. The matter is now in the hands of Congress. The Great Ape Protection and Cost Savings Act will, if passed, severely constrict the use of primates in medical research.
Just how do dragonflies perform their aerobatic maneuvers to catch insects in mid-flight? In order to find out, researchers are attaching a miniature electronic chip to the insects which will record in-flight information from attachments to 16 neurons in the dragonfly’s nerve cord. The information will then be transmitted wirelessly to electronic measurement devices that will hopefully give researchers some clues as to how the dragonfly uses what it sees in order to make almost instantaneous and precise flight maneuvers.
Read more at New Scientist.
A fossil of a moth that is some 47 million years old is allowing scientists to estimate the color of ancient moths and butterflies. Like other insects, moths and butterflies use coloration to camouflage themselves from predators and to announce that they contain toxins and would not be a tasty treat. Coloration rarely survives in fossils. However, moths and butterflies rely not on pigment, but on the surface structure of their wings to reflect light in just the right way to produce vibrant colors. With that in mind, the scientists made use of an electron microscope to study the minute variations in the fossil moth’s wing surfaces. Then, using what is known about modern moths and butterflies, they were able to extrapolate the color of the fossilized moth. The result was a green and blue color that is surprisingly brilliant, if not psychedelic.
Read more at Wired.
A recent study concludes that hundreds of orangutans are killed each year in the Kalimantan region of Borneo. Killing the animals has become easier with the ready availability of automatic weapons and explosives. The survey estimates that between 750 and 1,790 Bornean orangutans are killed each year in the Kalimantan region. That number exceeds the tipping point for extinction: it is estimated that no more than 1% of the females can be killed each year before the population can no longer recover.
Read more at National Geographic.
A team of scientists, including representatives from the Agricultural Research Service arm of the U.S. Department of Agriculture, has been exploring ways to safeguard milk production while reducing the amount of antibiotics fed to cows. They now believe there may be a cost-effective alternative to antibiotics in the form of citrus byproducts. Apparently, when cows are fed orange or similar citrus pulp, a natural antibiotic effect can be achieved. The cows seem to tolerate the taste of the citrus additives. And it seems to work. In a test done with sheep, a tenfold decrease in Salmonella was measured in the intestines of the sheep.
Read more at Red Orbit.
PCBs (pentachlorobiphenyls) are widespread in today’s environment and have long been suspected of harmful effects on human health. A new study on turtles establishes that exposure to the chemical stunts their growth and bone development. The study used water that contained no greater concentration of PCBs than what is normally found in urban waterways. After several months, compared to a population of control turtles, the PCB exposed baby turtles were smaller, had less bone density and were less developed. Because concentrations of chemicals such as PCB increase in concentration for animals higher up the food chain, the study raises further concerns about PCBs and human health.
Read more at Red Orbit.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
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