* Snakes in the 'Glades * Launching the Little Ice Age * Super-sizing Mammals * Arrival of the Arctic Killers * Levitating Flies * The Long and Fast of It *



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Snakes in the 'Glades
python_everglades.jpg Burmese python in the Everglades (Wikimedia Commons)

The Burmese python is native to Southern and Southeast Asia. It is a constrictor and one of the largest snakes in the world. Burmese pythons became popular pets in the United States decades ago. Since then, their release into the wild has created a huge ecological problem throughout Florida's Everglades National Park. In the rich Everglades the pythons bred like rabbits, and ate like wolves.  A new study by Dr. Michael Dorcas from the Department of Biology at Davidson College in North Carolina has revealed the extent of that problem for the first time.  The pythons' prey, mid-sized mammals and birds, seem to be crashing catastrophically. The raccoon population has decreased by 99%, opossums by 98% and the bobcat population is down 87%.  Rabbits and foxes have effectively disappeared. Several of the birds being preyed on by the python are already on the endangered list, and their fate is unknown. The overall ecological health of the Everglades is threatened because at present there is no way of controlling the Burmese python population.
          
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Launching the Little Ice Age

iceage-medium.jpg (University of Colorado Boulder)
The Little Ice Age put Europe in a deep freeze for hundreds of years, up until the early 19th century.  However, researchers have never agreed on the cause and the exact time of onset for this long cooling trend in the Northern Hemisphere.  New research by Dr. Gifford Miller, a professor of geological sciences at the University of Colorado, Boulder, and the Institute of Arctic and Alpine Research, and his colleagues, may have solved the puzzle. They have dated recently exposed frozen plants from under retreating ice caps on Baffin Island. Those plants turn out to have been frozen in just as the Little Ice Age was starting. The abruptness of the cooling that froze them led to a scenario in which multiple volcanic eruptions at the end of the thirteenth century cooled the north, and triggered a feedback loop that kept things cold for half a millennium.      

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Super-sizing Mammals

800px-Indricothere_CAS.jpg LIfe-sized model of Indricotherium, a horneless rhino that was the largest land mammal that ever lived (WolfmanSF/Wikimedia Commons)
During the Age of Dinosaurs, all mammals were small. But after the dinosaurs died out, some mammals -- including certain lineages of elephants, rhinos and whales -- grew to gargantuan proportions. An international team of scientists, including Dr. Jessica Theodor of the University of Calgary, recently compiled a database of the largest mammals through the ages to learn how these size changes evolved. They found that on average, it took at least 24 million generations for a land mammal to go from mouse-sized to elephant-sized, but the same size change took just half that number of generations for marine mammals such as whales. The researchers also found that mammals can go from super-sized to small again 10 times as fast as they grew, as in the case of some island-dwelling dwarf mammoths and elephants. Dr. Theodor provided some insights into the reasons for these trends and explained why size matters.

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Arrival of the Arctic Killers

Walrus_Hunters_1999-04-03.jpg Inuit hunters like these help scientists with 'traditional ecological knowledge.' (Wkimedia Commons)
The declines in seasonal Arctic sea ice has opened northern waters to killer whales or orcas, who have recently increased their range into areas where they were previously rare or unknown.  However, the hunting and dietary habits of orcas in the north are not well understood, so estimating the impact on other wildlife of this fearsome predator has been a challenge. Dr. Steven Ferguson, a marine biologist from the Department of Fisheries and Oceans and the University of Manitoba, enlisted the help of over 100 Inuit hunters and elders, whose knowledge of arctic ecosystems has been honed by generations of life on the land, sea and ice, to help fill in the picture of killer whale behaviour in the North. The Inuit described killer whales eating  ringed, harp, bearded and hooded seals, as well as other whales, including narwhal, bowhead and beluga. It is hoped that this combination of scientific knowledge and traditional observation can be a powerful tool in understanding changes in the Arctic.

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Levitating Flies



Fruit flies can be levitated right off the floor of their container and kept weightless for weeks, right here on Earth. In a recent study, Dr. Richard Hill of the University of Nottingham and his colleagues used a superconducting magnet and a technique called diamagnetic levitation to create a controlled, weightless environment on Earth. They say the levitated flies behaved just like a group of fruit flies did when they were sent into space. This suggests their levitation technique could be used for long-term research on the effect of zero gravity on living organisms that might help prepare us for longer journeys in space.

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The Long and Fast of It

800px-Sprinter_at_starting_block.jpg Sprinter at a starting block (Wikimedia Commons)
The foot bones and ankle structure of sprinters are different from those of non-sprinters. In fact the foot and ankle construction in the fastest among us is similar to that of animals known for their speed, including cheetahs and greyhounds.  According to a new study by Josh Baxter, a graduate student in the Department of Kinesiology at Penn State University, sprinters have a long fore-foot (the part in front of the ankle) and reduced leverage in the Achilles tendon. These characteristics permit sprinters to generate greater contact force between the foot and the ground and to maintain that force for a longer time. Over a shorter distance like a sprint, this provides an advantage. It is not clear whether we are born with these traits or if they are result of training, but it is hoped that understanding this mechanism in sprinters can be applied to those who have difficulty walking.   
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0