In the months before a raccoon attempted to push its way through her kitchen ceiling, Irizarry says she’d seen others lurking around on the fire escape outside of her living room.

This is mainly developmental – a young dog will experience distress in the moment: “I’m on my own and I don’t like it.” As it gets older, Firth says, “it will start to worry that it’s going to have that horrible feeling – worry about worrying, which is essentially what anxiety is.