Just as much as any human that isn't me, as far as I can tell from all available evidence.
So, yes, I absolutely believe they grieve, just like I believe humans who aren't me grieve.
Thanks, stranger.
I'm old enough that I have experienced significant grief a few times in my life.
Given our mortality, we should welcome some degree of situational grief, as grief is the absence of a previous love that we were lucky enough to experience in the first place.
Of course, there are also profoundly unfair versions of grief (like the loss of a child) that I wish nobody (or no whale, for that matter) would ever have to experience.
It doesn't mean "I've never felt grief".
Here's an article about orcas: https://www.bbc.co.uk/news/science-environment-64559047
It seems that an orca invests so much in a son that it's like an all-or-nothing one way ticket to pass her genes on. (She might get second try later, but the probability is much lower.)
No, they really don't. The article says
> indicated an inherent, strong maternal attachment to the calf
Yeah, that's not grieving.