That is actually called the cancer paradox.
It’s not quite clear whyly, but it is to be assumed that large animals simply are better at dealing with cancer.
On very fascinating idea is that of metacancer. The amount of cancer that would kill a person won’t bother a whale much, so it can keep growing until the cancer may get cancer…
As In rapidly growing cells that compete with the tumor.
And that, in effect limits it’s growth to manageable level’s.
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