* Smallest Giant * Maya Wall Calendar * Water Striders old Genes * The Nut-Cracker Chimps * White Dwarfs Snack on Planets * Geckos get in a Tailspin *


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The Smallest Giant

Dr. Victoria Herridge, a vertebrate paleontologist from the Natural History Museum in London, was combing through the basements of her museum when she found a fossil tooth discovered more than 100 years ago by pioneering explorer Dorothea Bate.  The tooth, discovered on the Greek island of Crete, had been originally identified as coming from a dwarf elephant.  Dr. Herridge realized that the tooth was, in fact, from a Mammoth.  She retraced the steps of Dorothea Bate to find the original dig in Crete, and found bones from the fossil, which turned out to be the smallest dwarf mammoth ever known - only a bit over a meter tall at the shoulder.  Dwarf pachyderms of several species, it turns out, inhabited islands all over the Mediterranean, one to three-and-a-half million years ago.
          
Related Links
  • Paper in Proceedings of the Royal Society:B
  • Natural History Museum release
  • Nature News
  • Discovery News
  • GRRL Scientist blog in The Guardian
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Maya Wall Calendar

The city of Xultun is an ancient Maya settlement, located in present day Guatemala.  A structure recently excavated there has revealed rare Maya paintings, as well as evidence of astronomical tables relating to various calendrical cycles, including those of the moon, Mars and Venus.  The paintings, found on the inner walls of the structure, depict a Maya King, as well as a scribe holding a stylus.  The astronomical tables - a series of hieroglyphic bars and dots arranged in columns - are also found on the inner walls.  The excavation was recently carried out by Dr. William Saturno, a Professor of Archaeology at Boston University.  He believes the early 9th century structure was the workshop of the scribe depicted in the painting.  These findings are the oldest-known Mayan astronomical tables, as well as the first known instance of Mayan art painted on the walls of a dwelling.
 

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Water Striders Old Genes

waterstrider_2.jpgMale (left) and female (right) Rheumatobates rileyi water strider antennae. Courtesy Science/AAAS
Male water striders always have their antennae out for potential mates, but not to detect them.  Their antennae are elaborately modified into grasping limbs, which are specialized for restraining struggling females during mating.  Dr. Ehab Abouheif, Canada Research Chair in Evolutionary Developmental Biology at McGill University, and his colleagues have worked out the genetic modification that drove the evolution of these complex antennae.  They were then able to "turn back the clock" by reducing the expression of the critical gene at the critical time.  They found males without the antennae elaboration were far less capable of mating than the fully elaborated males.   
  

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The Nut-Cracker Chimps

chimp.jpg© MPI f.Evolutionary Anthropology/Sonja Metzger
Three separate communities of chimpanzees, living the same area of a National Park in the Ivory Coast, have evolved a significant cultural difference.  Lydia Luncz, a PhD student from the Max Plank Institute for Evolutionary Anthropology in Leipzig, Germany, has recently studied each group's preferred method of cracking nuts.  The tool of choice for one group is rocks, while the other two use different sizes of hardwood branches, specifically shaped to hammer open the shell of the Coula nut.  It is believed all the chimps know how to use both tools, but stay with the method that have learned from a parent.  It is also known that when a young female leaves her group to mate with a neighbouring male, she will adopt the nut-cracking method of her mate.  The study shows that cultural differences can arise, even when the groups are genetically the same and in the same ecological niche.
 
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White Dwarfs Snack on Planets

white_dwarf_eating.jpgArtist's impression of a white dwarf surrounded by rocky dust cloud. 
As stars like our Sun age, they grow into Red Giants as they slowly exhaust their hydrogen and helium fuel.  Then, when the fuel is all gone, they blow off their outer shells and a super-dense, slowly cooling husk called a White Dwarf is all that remains.  Using the Hubble Space Telescope, Professor Boris Gänsicke of the Department of Physics at the University of Warwick, and his colleagues, have found four white dwarf stars that appear to be snacking on a continuous flow of dust.  The dust consists of oxygen, carbon, and metals like silicon, iron and magnesium, which are the primary constituents of terrestrial planets like the Earth.  Prof. Gänsicke suspects that gravitational disturbances due to the changing mass of the star may have caused collisions between the planets orbiting these stars, shattering them.  Now all that is left is the dust that the stars are slowly accreting.
 
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Geckos Get in a Tailspin

leopard_gecko.jpgLeopard Gecko, copyright Jerome66
The leopard gecko is common in the desert regions of Pakistan and Iran.  It is one of the larger geckos, measuring from about 20 to 28 centimetres in length, including its tail.  The gecko exhibits an unusual behavioural trait known as autotomy - voluntarily choosing to lose an appendage.  In this case, that appendage is the tail.  When a predator attacks, a combination of muscle spasms as well as a fracture in the tail-bone allow the tail to be jettisoned quickly.  The gecko is able to escape for a couple of reasons.  It is lighter and faster without a tail, but also because the tail is able to keep moving and create a distraction.  Dr. Anthony Russell, a professor of Biological Sciences at the University of Calgary, has discovered that electrical activity in the tail allows muscles to keep firing for up to 30 minutes.  As the tail jumps and flips and distracts the predator, the gecko is able to reach safety. 
 
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0