One thing about lifespan I think we need to make clear is “sample bias”.
I’m left-handed, and I was quite aghast a few years ago when I read that left-handed people live on average nine years less than right-handed people! I wondered, how is that possible?
So I recently looked it up, and the answer was in the way the study had been made. It came from a study decades ago, when they had looked up 2000 dead people, contacted their relatives and asked if the dead person was left- or right-handed.
And what they found, was, like I said, left-handed people live on average nine years less.
But they had made a mistake, in that they had forgot to consider something.
Long ago, in the first half of the last century and before, it was not acceptable to be left-handed. Children were forced to use their right hand in school (this happened to my grandfather), and in severe cases, their left hand was tied behind their backs. So they became right-handed.
So in that study, any people that were left-handed would have HAD to have died young, because before, there *were* almost no left-handed people. So “left-handed people live nine years less” is false.
This is how I see the current discussion on orca lifespan.
Orca captivity is 50 years old this year.
50-60 years is considered average lifespan for females, and maximum lifespan for males. Neither male nor female has had any chance of reaching their maximum lifespan yet, and females have barely had enough time to reach their average.
So how could we possibly compare the captive population with wild whales that are 50, 60, 70 and more years old? How can anyone possibly think that’s fair? There is going to be a huge “sample bias”.
What I would be interested in, is if we would count only wild whales born since the 60s or 70s (captivity in those days was very poor so I don’t see that as really fair either), and then still, the captive population is really small.
So skip all the wild whales born before the 60s or 70s (there are no and were never any captive whales born before then), and only use as many (random) wild whales as there are captive examples.
Then I think we would get a much more *honest* calculation.
(Also, remember that, according to the document “Conservation Plan for Southern Resident Killer Whales”, life expectancy at birth is as low as 29 for females and 17 for males - and that is raised to 50-60 for females and 29 for males once they reach adolescence, which means many wild orcas die young.)