But they're still bears, right? They're not turning into seals, or puffins, or lemmings (or cats).

Of course they're not - why would they? A bear turning into a cat would magic, not evolution. As for half-creatures etc, this is a creationist straw an argument. Every living thing is at some evolutionary point, there are not quantifiable fractions.

Methinks you're on a windup here Iona.