Anything can be explained away depending on which variables you take into account.

Some people like heated toilet seats. Maybe most dogs like some warm sunhine on their behinds while pooping.

Or maybe they want to face upwind for other reasons.

If predators attack with the sun behind them then shouldn’t dogs look into the sun to protect themselves?

Dogs look to their pack for protection while doing their business. If your dog stares at you while he's pooping, this is why. It's also why he might follow you into the bathroom... to keep you safe while you do your business.

But dogs are descended from wolves, which I think are apex predators, and were domesticated by humans, another apex predator.

> Predators even don't like the sun in their eyes, that's why they attack with sun behind them, if they can.

While I have no doubt that predators don't like having the sun in their eyes, they would obviously still prefer to attack with the sun behind them even if they didn't care. It's very advantageous, because the prey doesn't like having the sun in its eyes.

Attacking with the sun behind you is to prey with eyes what attacking from downwind is to prey with noses.

Dogs are predators. We've domesticated a lot of that out of them, sure, but they've got the eyes facing forward and carnivore digestive tract. What would be higher to a wild dog or wolf in the wild?

Actually dogs & wolves have jaws and digestive tracts consistent with omnivores which are significantly longer than that of carnivores.

Correct. They can digest quite a bit of plant matter.

Cats, on the other hand, are carnivores.

I had a cat who liked tomato. It was weird.