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Past Shows
December 13, 2008
 Download an MP3 of the entire program (22MB).
Red Men, Green Women
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Male or Female? courtesy M. Tarr.
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If you happen to notice that the men you know tend to be a bit redder than the women, and the women tend to be a bit greener, it's not because of sunburn and bad seafood. Dr. Michael J Tarr, a professor of Cognitive and Linguistic Sciences at Brown University in Rhode Island, has discovered that we are, in fact, gender-specifically tinted. What's more, we subconsciously know it, and use this colour perception as part of the repertoire of things that helps us tell males from females.
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Spider Size Doesn't Matter
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A female redback spider (above) with a smaller male, courtesy M Kasumovic
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There is perhaps no better testament to the male sex-drive than the perseverence of the male redback spider. Not only will male redbacks court females for several hours for a chance to mate, they do it despite the fact that copulation is lethal for them -- female redbacks dine on their mate once they have been fertilized. However, that's no deterrent; males still clamour to get a mate. In fact, Dr. Michael Kasumovic, a Canadian post-doctoral fellow at the University of New South Wales in Sydney, Australia, has discovered an interesting competitive behaviour in redback males. Dr. Kasumovic found that when there are plenty of females in a spider population, young redback males will actually cut their physical development short, in order to go on the prowl for a mate. This means that they tend to be a lot smaller than fully-developed males. However, the head start gives them a competitive edge, despite their smaller size.
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Captive Elements
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There's been a long-standing debate about whether zoos are a good thing or not for elephants. On one hand, captive animals don't have to deal with food shortages, disease or drought; on the other hand, they're often separated from their family group, put in a relatively confined space and moved from one zoo to the next. But until now, this simply hasn't been studied rigorously enough to draw any concrete conclusions. However, Dr. Georgia Mason, Canada Research Chair in Animal Welfare at University of Guelph, has recently completed a study that does just this. Her conclusion: that zoos are, indeed, detrimental to elephants' well-being. When Dr. Mason compared the life span of elephants in zoos across Europe to those in protected reservations in Kenya and Myanmar, she found that often the captive elephants lived only about half as long as their wild kin. The most likely causes for captive elephant's shortened lives? Most likely obesity and stress, says Dr. Mason.
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Mandible Mayhem
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Termite soldier, courtesy J. Niven
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Termites are mild-mannered little creatures, hiding away in their mounds, peacefully chewing up wood. They do have to defend themselves, though, and it turns out they're very good at it. Dr. Jeremy Niven, a research scientist in Zoology at the University of Cambridge in England, working at the Smithsonian Tropical Research Institute, has discovered that the termite uses its mandibles in a unique way to deliver a blow capable of killing an ant or invading termite in a single strike. They snap their jaws at a speed of up to 250 km/h, striking with a speed unequaled by any other animal.
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Disturbed Birds
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Dr. Isabelle-Anne Bisson was interested in whether human activity in their habitat was bad for small songbirds, so she designed an experiment to basically ruffle their feathers. By tracking the birds and monitoring their heart-rate as researchers chased them through the woods, made noise near their nests and woke them at night, Bisson and her team were able to determine if human disturbance alarmed the birds and caused them to use too much energy. To her surprise, she discovered that the birds quickly adapted, and ignored the human disturbance, once they realized it represented no real threat. Dr. Bisson is a Canadian postdoctoral fellow in the department of Ecology and Evolutionary Biology at Princeton University.
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Sipping Snakes
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Sea snakes had been thought, like other sea animals, to drink sea water when thirsty. No so, according to Dr. Harvey Lillywhite, a professor of Zoology at the University of Florida. Sea snakes may not have mastered the trick of filtering salt from seawater as marine mammals have done, and so must find fresh water, even when at sea. Dr. Lillywhite thinks that one significant source of water for them may be the thin layer of fresh rainwater that exists on the surface of the ocean, before it has a chance to mix with the salt water below.
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Theme music bed copyright Raphaël Gluckstein. Creative Commons License by-nc-nd-2.0
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