Wednesday, April 4, 2018

A Swim With A Greenland Shark

Image result for greenland shark

Environmental & Science Education
Edward Hessler

Greenland sharks have the potential to live a long life, the longest of all living vertebrates.

This short video is about an encounter with one. If you've not seen this shark before it may surprise you. It is not a fast predator and appears sluggish.

However, beware of age claims in press reports. You will notice that the shark being filmed is reported to be 512 years old. Tain't necessarily so.

In a study of 28 female Greenland sharks, scientists reported an age probability range, from at least 272 years old to "could probably be 512 years old." The video was embedded in a fuller story by M. R. O'Conner in the New Yorker. Read it if you want to know more about the details of the study as well as the behavior of the shark.

One phrase I don't like in O'Conner's essay is "In theory...". Theories are much richer and more complex than this simple statement. I'd much have preferred mention of evidence but that would have added a few more words to the story.

Image result for greenland sharkThe glossary of Understanding Evolution, a website at the University of California-Berkeley defines theory as "A broad explanation for a wide range of phenomena. Theories are concise, coherent, systematic, predictive, and broadly applicable. They usually integrate many individual hypotheses. A scientific theory must be testable with evidence from the natural world. If a theory can't be tested with experimental results, observation, or some other means, then it is not a scientific theory."

Still this is a lovely film about a critter that is hard to study, seldom seen and which has a life history that remains very incomplete.

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