For cats: my youngest miss Penelope was a ferel rescue, she seems to have adapted fine to being an indoor cat. She LOVES to look out the window, but she has never tried to escape out the door when someone goes out, happily. I think she likes knowing where her next meal is coming from... I've had cats my whole adult life, so far maybe I've just been lucky, but they've been pretty adaptable for all that cats ALSO think they rule the world.... we had a dog when I was a kid, but I so much prefer cats.