Shark Embryos Cannibalize Their Siblings * Does Antimatter have Anti-gravity? * Humpbacks Take Fishing Tips From Friends * My Beloved Brontosaurus * Question Period - Moon's Moons

Listen

OK, Imagine a dinosaur.  Nope, you're wrong.  That's pretty much the lesson from a our guest today who's written a new book which examines why much of the popular image of dinosaurs is outdated, and hasn't kept up with the latest scientific understanding of these magnificent beasts.  Plus we'll hear how a single humpback whale might have changed the feeding habits of hundreds of others;  we'll learn how a Canadian scientist is trying to figure out  whether antimatter falls up or down; and we'll find out if the moon can have its own moon.  But first, Jaws - the very early years.

 

play-icon.jpg Listen to the whole show (pop up player) or use this link to download an mp3.



Shark Embryos Cannibalize Their Siblings

sand_tiger_shark.jpg
Sand tiger shark, copyright Jeff Kubina.
Sand Tiger Sharks are found in coastal regions all over the world.  On average, they are about 2 1/2 metres in length, but can grow much larger.  The females mate with several males and will carry as many as a dozen embryos, divided between two uteri.  However, only one from each uterus will survive.  The reason is that the the most advanced embryos - those who develop eyes and teeth first - cannibalize all of their siblings.  New research by Dr. Demian Chapman, an Assistant Professor from The School of Marine and Atmospheric Science at Stony Brook University in New York, has determined that shark pup survival may be related to order of mating.  Also, DNA analysis shows that 60 percent of the time, the surviving pups come from the same father.  As a result of their cannibalistic behaviour, the pups are 1 metre in length when hatched, making it easier for them to survive in the wild.

Related Links


play-icon.jpgListen to this item (pop up player) or use this link to download an mp3.




Does Antimatter have Anti-gravity?

alpha_apparatus.jpg
ALPHA apparatus, courtesy CERN

Antimatter has many strange properties, but one thing we don't know about it yet is whether gravity affects it in the same way it does normal matter.  In other words, does antimatter fall up or down?  This is a difficult question to answer, since we can only study antimatter in tiny amounts - atoms at a time - and because of its tendency to blow up whenever it touches normal matter.  Researchers have been trying to study this with the ALPHA experiment at CERN, the home of the Large Hadron Collider.  Dr. Robert Thompson, a professor of physics at the University of Calgary, and his colleagues, have been studying anti-hydrogen atoms they've trapped, and have devised an experiment to see if this anti-hydrogen behaves like regular hydrogen under gravity.

Related Links


play-icon.jpgListen to this item (pop up player) or use this link to download an mp3.




Humpbacks Take Fishing Tips From Friends

lobtailing_whale.jpg
A humpback whale lobtailing.   Photo: Jennifer Allen & Ocean Alliance.

Humpback whales normally hunt by swimming below a school of prey, blowing air bubbles, then lunging upwards toward the bubbles, taking in as many fish as possible.  The bubbles make the fish swim in a tighter school.  But in 1980, a lone humpback in the Gulf of Maine was observed adding a new element to that routine.  It preceded those foraging steps by slapping its tail on the water several times - a behaviour known as lobtail feeding.  It may be related to a change in the availability of herring, the humpback's favourite prey, at that time.  New research by Jenny Allen, a Marine Mammal Biology student at the University of St. Andrews in Scotland has found that, over the years, that behaviour has spread throughout that population.  Just as these whales are known to transmit songs from one to another, it is thought that lobtail feeding is a similar example of cultural learning in humpbacks. 

Related Links


play-icon.jpgListen to this item (pop up player) or use this link to download an mp3.




My Beloved Brontosaurus

beloved_brontosaurus.jpg
 
Many people have wonderful childhood memories of their favourite dinosaur, especially the magnificent Brontosaurus. The only problem is that scientists have known for more than a century that there is no such thing as a Brontosaurus. It is actually an Apatosaurus that was mistaken for a new species.  Correcting the dinosaur myths of our childhood has become a bit of an obsession for Brian Switek. The American science writer and self-described dinosaur fanatic says that popular culture has not kept up with the rapid pace of scientific discovery. And we may have to let go of many of our most cherished childhood dinosaur beliefs.  Brian Switek's latest book is called, My Beloved Brontosaurus: On the road with old bones, new science and our favourite dinosaurs.

Related Links



Listen to this itemplay-icon.jpg (pop up player) or use this link to download an mp3.



Quirks Question Period - The Moon's moon

This is another episode of our occasional feature, the Quirks & Quarks Question Period.  You think of a question, and we'll ask a Canadian scientist to tell us the answer.  And today's question comes from Ed Feuer of Winnipeg.  He wanted to know if a moon can have its own orbiting moon, and if so, are there any examples in our Solar System?  To help us answer this question, we contacted Dr. Vicky Kaspi from the Department of Physics at McGill University in Montreal.  She says a moon might have a temporary asteroid orbiting it, but it wouldn't last - due to the gravitational pull of the planet.

Listen to this itemplay-icon.jpg (pop up player) or use this link to download an mp3.




Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0