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A comment on Canada to ban keeping whales, dolphins in captivity. Parent comment

Re:Canada to ban keeping whales, dolphins in captivity by marvin-83 on Tuesday June 11, 2019 @08:52AM (#20154913)
From the study that Marino & Frohoff (2011) cites for orca whale lifespan in the wild:

> Using data from between 1973-4 and 1987, females have a mean life expectancy of 50.2 yr

How is this possible? I don't understand how a 14 year observation window allows someone to observe an average life expectancy of 50 years.

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Re:Canada to ban keeping whales, dolphins in captivity by moate on Tuesday June 11, 2019 @09:28AM (#20155177)
Because they're able to tell how old the whale is when it died. They're not observing whales from birth to death in each instance. If you tried to do that, you'd be unable to speak on life expectancy on species with lifespans greater than like 10 years.
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Re:Canada to ban keeping whales, dolphins in captivity by marvin-83 on Tuesday June 11, 2019 @09:36AM (#20155233)
by autopsy? Or is there clear external physiology that indicates the age?
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Re:Canada to ban keeping whales, dolphins in captivity by moate on Tuesday June 11, 2019 @02:24PM (#20158108)
https://www.quora.com/How-do-biologists-tell-the-age-of-a-wh...

Quick and dirty: size is a pretty good indicator to approximate, but if you've got yourself a dead whale you can check the bones to get a better number.

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