A young woman sitting across from me on a nearly-empty F train catches my attention. She appears to be in her late teens or early twenties, and she’s absorbed in her phone, wireless headphones clamped over her ears. She’s dressed in loose-fitting ‘athleisure’ wear, and it’s her half-unzipped jacket that stands out: something is moving inside of it. My first assumption is that she has a tiny dog tucked inside her jacket – for this is by no means an uncommon sight in the subway. Could a dog be this small? Whatever it is, its movements aren’t enough to draw her attention away from her device, and it’s clear that whatever kind of creature is burrowing inside her jacket, its presence is something she’s used to. My attention drifts away as the train makes a few more stops and passengers enter and exit. In the long tunnel between East Broadway and my stop at York Street my eyes settle again on the young woman. Her jacket continues to show signs of movement, and then, finally, a pointy, furry nose pokes out of the open zipper: her pet is a large brown rat.