I think he just loved being with the bears because they didn't make him feel bad. I get it too. When he was with the bears, they didn't care that he was kind of weird, or that he'd gotten into trouble for drinking too much and using drugs(which apparently he did a lot of). They didn't ask him a bunch of stupid questions about how he felt, or why he did what he did. They just let him be who he was.

Walter had never liked cats. They'd seemed to him the sociopaths of the pet world, a species domesticated as an evil necessary for the control of rodents and subsequently fetishized the way unhappy countries fetishize their militaries, saluting the uniforms of killers as cat owners stroke their animals' lovely fur and forgive their claws and fangs. He'd never seen anything in a cat's face but simpering incuriosity and self-interest; you only had to tease one with a mouse-toy to see where it's true heart lay...cats were all about using people

Animal companions come into your life for an infinite number of reasons, each one being in service to you, your current life experience, and moreover, your soul's growth and evolution.

I wish people were more like animals. Animals don't try to change you or make you fit in. They just enjoy the pleasure of your company. Animals aren't conditional about friendships. Animals like you just the way you are. They listen to your problems, they comfort you when you're sad, and all they ask in return is a little kindness.

You always fed strays and bent down to talk to the dogs you met on the street, looking straight into their eyes as if they were old friends. (Maybe they are, you said. From another life.) You liked to go to the pound and look at them. You tried to send them messages of comfort. I couldn’t go because I started crying the one time I tried. All those eyes and the barks like sobs.