> It is not a matter of opinion that orca whales, bottlenose dolphins and beluga whales die prematurely when kept in captive settings, but rather a potent and recurring reality. Marino & Frohoff (2011) show that this is especially and most dramatically seen in the orca whale, with males living on average 29.2 years in the wild with an observed maximum of 60 years, and females living 50.2 years on average with an observed maximum of 90 years. Their naturally extensive lifespan is shortened severely when they are placed in captive environments, with few orcas living past the age of 20 in captivity (p. 3)
> Many cetaceans in captivity develop stereotypies, or unnatural, often purposeless behaviors that can be a manifestation of poor mental health. Such behaviors include repetitive pacing, swaying, head-bobbing or circling, and bar-biting (Cetacean Inspiration, 2011). One of the most prominent stereotypies noticed in these whales is an activity known as slide outs. The whale will slide out of the water and sit motionless, sometimes for 10 minutes at a time (Cetacean Inspiration, 2011). This creates safety issues for the guests of marine mammal parks like SeaWorld. If a whale did this in the wild for too long of a time the weight of the whale could crush its own internal organs (Cetacean Inspiration, 2011).
See also the Blackfish documentary (which seem to have left Netflix sadly). Almost all captive male orcas have a floppy dorsal fin, that is a definite sign of ill health and seldom happens in the wild.
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.
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.
Ric O'Barry, former trainer of the dolphins used for the 'Flipper' TV show (now animal rights activist) tells a story in the documentary 'The Cove' how one of the dolphins swam up to him one day, looked him in the eye, took a last breath and then sank to the bottom of the tank and died [1]. Given that dolphins have to make a conscious choice for every breath they take gives some indication for a conscious decision for suicide.
Eh. . . . yeah? I'm not sure that's a very strong criticism. We're much more similar to other mammals than we are different from them, so our understanding of human behavior provides a very strong basis for understanding other animals' behaviors.
> Many cetaceans in captivity develop stereotypies, or unnatural, often purposeless behaviors that can be a manifestation of poor mental health. Such behaviors include repetitive pacing, swaying, head-bobbing or circling, and bar-biting (Cetacean Inspiration, 2011). One of the most prominent stereotypies noticed in these whales is an activity known as slide outs. The whale will slide out of the water and sit motionless, sometimes for 10 minutes at a time (Cetacean Inspiration, 2011). This creates safety issues for the guests of marine mammal parks like SeaWorld. If a whale did this in the wild for too long of a time the weight of the whale could crush its own internal organs (Cetacean Inspiration, 2011).
https://blogs.umass.edu/natsci397a-eross/the-detriments-of-c...