Whale Shark Littering

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Whale Shark Littering Photo courtesy Jennifer Schmidt, copyright University of Illinois Board of Trustees

Whale sharks are found in oceans all over the world, including the Atlantic, Pacific and Indian. They are normally 12 to 13 metres in length, but can be as long as 20 metres, making the whale shark the world's biggest fish. Despite its size, it is elusive and therefore difficult to study. That's why, when Dr. Jennifer Schmidt, from the Department of Biological Sciences at the University of Illinois in Chicago had the chance to study frozen embryos from a female that had been caught in 1995, she was very surprised to discover it had been carrying 304 embryos, an astounding number. The embryos were in various stages of development, and genetic analysis revealed they were all from the same father. This suggests that the female whale shark stores sperm from a single mating, then fertilizes her own eggs as she sees fit.

(A radio interview I did for a Canadian science show called Quirks & Quarks was broadcast a couple weeks ago, and the podcast is on-line at their site: http://www.cbc.ca/quirks/episode/2010/10/02/october-2-2010/ )