I realize you can just answer, “mysterious aliens beyond our understanding,” but why would a space probe have a mandate of either talk to a whale for 30 seconds or destroy Earth and disable everything in its path on the way to Earth?
Why? What does that achieve?
I haven’t been following closely, but the last couple of potential sightings I’ve read about have been unconfirmed and certainly nobody’s captured one or even a picture of one sufficient for a positive ID lately.
Its status is officially “functionally extinct” which does not necessarily rule out that some individuals may remain somewhere, but researchers are pretty much agreed that however many might be left in hiding (if any) probably aren’t enough to sustain any kind of ongoing population.
As Granny Weatherwax famously observed, just one of anything doesn’t work. If you only have e.g. one dolphin left, maybe it’s not technically extinct, but that doesn’t do you any good without a mate. Same deal if there are enough of them in nooks and crannies to theoretically breed but they’re all geographically disparate and can’t reach each other.
Or if you prefer:
Yeah, even Wikipedia goes with “probably extinct.” How sad.
Anyway, it’s an amazing book. There was also a radio series which is decent (I believe you can get it on the Internet Archive) and Stephen Fry did a follow-up TV series around 15 years go.