Saturday January 19, 2008
Solving Syphilis, Squirrels Eating Snake Skin, Seal Sounds, Mistakes Were Made, Fact or Fiction: Too Cold to Snow
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Solving Syphilis
Columbus in the New World
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Medical historians have always assumed Christopher Columbus had more than the travel bug. It's long been thought he and his men brought back syphilis when they returned to Europe. It's a theory based on historical records, more than scientific evidence. However, Dr. Michael Silverman and his colleagues recently discovered genetic evidence that backs this up, while treating tropical diseases in Guyana. Dr. Silverman, an infectious diseases physician with the charitable organization Ve'ahavta and an Assistant Professor at the University of Toronto, noticed peculiar skin sores on the arms and legs of children he was treating in the remote Guyanese jungles. The sores looked like syphilis, but he thought it was rather strange they were on the limbs and not the genitals. It turns out the sores were caused by a disease called yaws, which is caused by a non-venereal bacteria related to syphilis. Genetic tests of the Guyanese yaws revealed that it's likely to be the evolutionary ancestor of the infamous venereal disease. Dr. Silverman thinks Columbus and his men picked up yaws during their amorous liaisons with the New World natives. The disease was carried back to Europe where it quickly evolved into the virulent venereal bug we know today.
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Related Links
Dr. Silverman's paper in the PLoS journal, Neglected Tropical DiseasesVe'ahavta, the medical charity Dr. Silverman works withCBC News story on Dr. Silverman's findingSquirrels Eating Snake Skin
Eating Snake Skin, courtesy B. Clucas |
When Barbara Clucas started her doctorate at UC Davis, her supervisor informed her of a strange phenomenon he'd observed. When California Ground Squirrels came across a spot where a rattlesnake had been lounging, the squirrel would start rubbing around and eating the grass where the rattler had been. Ms. Clucas wondered why ground squirrels would perform such maneuvers and decided to study this in more detail. Using discarded snake skins as bate, she was able to see ground squirrels chew up the skins, and then cover themselves in snake-scented saliva. Further research showed the squirrels were using the scent as a cloaking device to protect themselves from predatory rattlesnakes.
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Related Links
Ms. Clucas' WebpageMs. Clucas' paper in Animal BehaviourMs. Clucas' paper in Proceedings of the Royal Society BRelease from UC Davis on the ResearchSeal Sounds
A Weddell seal. Courtesy Michael Van Woert, NOAA NESDIS, ORA |
Just as you can tell whether someone comes from Brooklyn or Newfoundland by the way they speak, Weddell seals also have their own dialects. Dr. Jack Terhune, a biologist at the University of New Brunswick in Saint John, has been studying the vocalizations of Weddell seals off the coast of Antarctica. Dr. Terhune and his colleagues studied the sounds male seals make when they're defending their territory. Weddell seals make these sounds -- called trills -- by essentially humming incredibly loudly. Not only are trills loud (they can travel over 30 km underwater) and eerie, but they differ from region to region around the Antarctic continent. Dr. Terhune was surprised to find that even relatively close neighbors spoke different dialects, suggesting that the various seal clans don't do much social mixing.
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Mistakes Were Made
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The human mind has a built-in mechanism for helping us escape the painful psychological penalty of bad decisions - mistakes, in essence. The benefit of this is that we can make decisions without paralysis. The cost, on the other hand, is what psychologists Carol Tavris and Elliot Aronson explore in their new book, Mistakes Were Made (but not by me): Why we justify Foolish Beliefs, Bad Decisions and Hurtful Acts. They look at why human decision-making predisposes us to sometimes make mistakes even worse by mechanisms of self-justification and confirmation bias - which causes us to reinforce our decisions and beliefs (even mistaken ones) ever more strongly. The implications of this for our personal lives, as well as for social structure and politics, they say, are important to understand. We spoke with Dr. Tavris, an independent social psychologist and writer.
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Fact or Fiction: Too Cold to Snow
From time to time, we present a commonly held idea or popular saying - and ask a Canadian scientist to set us straight on whether we should believe it or not.
Today's popular aphorism: If the temperature outside is too low, it cannot snow.
With the answer is Dr. Glen Lesins at Dalhousie University's Department of Physics and Atmospheric Science.
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Theme music copyright Raphaël Gluckstein. Creative Commons License by-nc-nd-2.0
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