Neanderthals Still Captivate and Confuse.
The more closely scientists compare H. sapiens and Neanderthal DNA the more confusing things seem to become. It is clear that modern humans of European and Asian ancestry carry significant traces of the same DNA that has been found in Neanderthal fossils. This could mean that the two interbred after modern humans migrated to the Middle East and Europe 60,000 years ago. In fact, some scientists theorize that Neanderthals weren’t so much exterminated by modern humans as they were absorbed into our gene pool. This is supported by the fact that modern indiginous Africans have viturally no Neanderthal DNA. On the other hand, hard to explain facts such as a larger percentage of Neanderthal DNA in Asian and South American natives could mean that the genes are reflecting a more distant relationship: that humans and Neanderthals had a common ancestor dating much further back in time.
More at National Geographic.
Expeditions to uncover dinosaur fossils are time consuming, expensive and sometimes unnecessary. University of Chicago paleontologist Paul C. Sereno did not have to go very far at all to re-discover an important fossil. It was hiding in plain sight in Harvard’s Natural History Museum. Already in the possession of the museum, albeit in a backroom, was a spectacular specimen of Pegomastax africanus, a new species of dinosaur that had been waiting for scientific attention since the 1960’s.
More at The Crimson.
The 25 Most Endangered Primates.
Recently released research by the International Union for Conservation of Nature (IUCN) finds that 25 primate species are on the brink of extinction. Of those, six species live on the isolated island of Madagascar. In one of the most extreme cases, a species of lemur native to Madagascar is believed to be represented by only 19 remaining individuals. But hope is not yet lost. Madagascar, with international help, has set up multiple animal reserves and sanctuaries.
More at Red Orbit.
Dinosaur DNA Lost Forever.
Scientists in Australia have worked out a more precise timeline for DNA deterioration. They based their estimates using the rate of DNA decay that they have documented for the now extinct moa bird, using specimens from 600 to 8,000 years old. The calculations suggest that fossil-encased DNA is completely destroyed after 6.8 million years. That means that the dinosaur DNA, wistfully recovered and reconstituted in Jurassic Park, will remain the stuff of science fiction. Still, since they estimate that fossil DNA can be sufficiently intact after 1 million years, there is still reason to believe that the remaining DNA in woolly mammoth aged fossils might eventually lead to cloning.
More at Discovery.
Left-eyed Finches Make Mating Miscues.
An experiment in which male Gouldian finches had their right eye covered with a patch found that they suffered mating miscues when forced to use only their left eye. These finches come in three varieties: yellow-heads, red-heads and black-heads and usually pursue potential mates of the same head color. With their right eye covered, however, the male finches became indiscriminate about the individuals they wooed, and were more awkward and ineffective in their mating routines as well. When the experimenters switched the patch to the left eye, the male finches resorted to their more typical mating behavior. Brain side bias is common in birds and has been detected in lizards and fish as well.
Drunk Zebra Finches Sing Off-key.
When given water laced with alcohol, Zebra finches sang their songs with more discordant notes. In the experiment, the birds were given enough alcohol to reach the equivalent of .08 percent blood alcohol — which happens to be legal limit for driving in most states. And when younger birds were given even less alcohol, experimenters found that their ability to learn songs from older finches was negatively impacted and possibly permanently so. Fortunately, there are no plans to observe the mating behavior of Gouldian finches who have their right eye covered while drunk.
More from New Scientist.
Wolf Coat Color Offers a Genetic Trade-off.
In Yellowstone Park the ratio between black-coated and grey-coated wolves is 50/50. Yet, it is well documented that grey-coated wolves have significantly greater reproductive success (more live births) than do black-coated wolves. What’s going on? Well, although greycoated wolves have a higher percentage of live births, black-coated pups have a higher survival rate. Scientists believe that the gene for black coats entered the grey wolf population thousands of years ago through mating with black dogs. It persists because it represents a trade-off between reproductive success and fitness to survive.
More at The Wildlife News.
For Jumping Spiders Even Eyes Come in Eights.
Jumping spiders (Salticidae family) have eight eyes and they put them to good use. With 360 degree panoramic vision, the spiders don’t miss much. In fact, nature’s heavy investment in vision makes these animals especially curious. In an article for Discovery News, Jennifer Viegas describes how these spiders are curious about people, videos and even attack a pulled thread just like a house cat would.
New Video of Bright Orange Sea Horse.
In the coastal waters of West Africa lives a colorful seahorse. It is overfished by local fishermen and yet poorly understood by scientists. This video of the seahorse in its native habitat is one of the rare occasions when it has been scientifically documented. Conservationist organizations are working with the Senegalese government to restrict the trade in these interesting but vanishing creatures.
More at National Geographic.
Re-cycling Exotic Animals.
The problem of exotic pets released into the wild is a serious one for some states. Florida, for instance, has been overwhelmed by pets, such as the burmese python, that have been discarded into the wild, reproduced in large numbers and have become a threat to native species. The Florida Fish and Wildlife Conservation Commission has come up with a possible solution. Residents can drop off their unwanted exotic pets to a commission office where it will be examined by a veterinarian and then shipped off to an organization that specializes in caring for the particular species of animal. The commission does not accept domestic pets, such as cats and dogs.
More at The Ledger.
“The Dirt: This Week in Nature” curated and written by Robert Raciti.
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