I didn't see that coming

Why do dogs eat things that aren't food? I feel like dogs should instinctively know the difference between food and non-food and that non-food shouldn't be eaten. Is that asking too much?

We have two dogs. Dylan is a Pembroke Welsh Corgi from a breeder and Autumn is a one-eyed pit mix from the shelter. And they hate each other.

Dylan usually only eats food. He also likes paper products, like cardboard and toilet paper.

Autumn will eat anything. Maybe it's because she's younger? I don't know.

Here is an inexhaustive list of the non-food items she likes to eat: poop, grass and other plants, tennis balls, soccer balls, plastic flower pots, rubber dog toys.

About a week and a half ago, I got distracted and didn't watch her closely enough and she ate most of one of these. I was a little concerned because... well, because it was a rubber dog toy and not food.

A few days later she was out in the backyard and I looked outside to check on her just in time to watch her throw up. To keep her from eating it, I grabbed her and put her back in the crate. As I cleaned up the puke, I noticed that there were chunks of red rubber ball in it.

Gross. That's what she gets for eating it in the first place and that's what I get for not paying her enough attention.

Then about a week later, we took Autumn for a long walk along the river. There were some people having a drunken party and they asked if she was friendly and if they could pet her. Of course! She loves people and loves attention! But as the guy reached out to pet her, she decided it was time to puke up more red rubber ball.

He was repulsed and decided he didn't want to pet her after all.

"What? That red rubber ball tasted good. I couldn't help it."