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Past Shows
Past Shows
November 22,
2003
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Monarch Troubles
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Monarch
butterflies - Courtesy Dr. Karen
Oberhauser |
Every year, millions of Monarch butterflies
make the migration from Canada and
the North-East United States, down
to Mexico. And once they're there,
the Monarchs settle on a small number
of mountain tops to overwinter. But
these wintering sites are changing,
due to global climate change. Dr.
Karen Oberhauser is an assistant
professor at the University of Minnesota.
She says that, in fifty years, the
mountain tops will probably be uninhabitable
for Monarchs.
Related Links
Amphibious Accents
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What
part of the pond are you from?
- Courtesy of the BBC |
As Henry Higgins discussed in the
musical, My Fair Lady, depending on
where you're from, your accent will
change. Now it turns out that humans
aren't the only creatures to show
vocal regional differences. Julia
Wycherley, a Ph.D. candidate at
the University of Sussex, has shown
that frogs have different accents,
too. In the pond frog of Europe, she's
found three distinct accents. These
accents show where the amphibians
originated, and how they've migrated
to their current homes.
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Baboon Heirarchy
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Baboon
females - Courtesy Dr. Dorothy
Cheney |
Humans seem almost unconsciously aware
of social rank. Whether it's a club,
a family or the workplace, we seem
to know where everyone fits into the
hierarchy. And we seem to understand
how important any changes to the hierarchy
are. After all, a change in rank in
a family might lead to hurt feelings,
while a change in rank between two
rival clans might lead to warfare.
Well, it turns out that humans aren't
the only primates who pay attention
to rank. The same is true of baboons.
Dr. Dorothy
Cheney, a biology professor
at the University of Pennsylvania
in Pittsburgh, studies these monkeys.
She's shown they pay close attention
to any changes that occur in their
social structure, and are able to
decide how important any rank changes
are to the whole troop.
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Links
Blind, Naked and Feeling
no Pain
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Painfree Mole-rat - Courtesy
Dr. Tom Park |
Naked mole-rats are very odd creatures
in many ways, but the strangest thing
about them might be the discovery
that they don't feel pain through
their skin. Dr.
Tom Park, a professor of
biology at the University of Illinois
at Chicago, has discovered that these
rodents are missing a critical neurotransmitter
that all other animals have. This
chemical normally communicates pain
signals from the skin to the central
nervous system. The animals otherwise
seem to have normal sensation in their
skin. It's an evolutionary mystery
why the mole-rats have lost this ability,
but studying them may help us understand
pain better.
Related
Links
It's Lonely at the
Top
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The
bigger, the more likely to face
extinction |
When you're a carnivore, bigger is
better - to a point. Dr.
Blaire Van Valkenburgh,
from UCLA, has studied the history
of dogs in North America. She's found
that species tend to evolve into larger
and larger dogs as time passes. But
these larger dogs end up with specialized
diets, and are more vulnerable to
environmental change. Which means
the species end up dying out sooner
than smaller dogs. It seems that getting
to the top of the food chain is a
death warrant for canine carnivores.
Related
Links
Question of the Week:
Egg and Sperm Size Variations
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Jay Ellenbogen in Ottawa writes:
"I've been told that the eggs of mammals
vary in size according to species.
Do sperm also vary in size?"
For the answer, we go to Dr. Peter
Flood who is an emeritus professor
at the Western College of Veterinary
Medicine.
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