It seems bizarre to framing this as something bears discovered about themselves, rather than something scientists discovered about bears. It's not like anybody actually asked bears what the bears know.
> Polar bear population discovered that [they] can survive without sea ice
But now I think it's supposed to be:
> Polar bear population [was] discovered that can survive without sea ice
The latter still seems awkward to me. Is it even grammatically correct?
the perils of headline-syntax