it was a lean young cat of indifferent character, somewhat whorish
I adore that the cat is described as somewhat whorish!

The sloth did come to love Jack eventually I feel, given that it would curl up on his knee. Of course, the sloth was also very heavily bribed...

Maybe it's because, unlike Stephen, Jack doesn't really love animals? He likes them, and respects them and recognises they are useful, but he's not really very interested in them as personalities.