I've always had an easier and deeper connection to animals than to humans. Animals have no hidden agendas and as someone else said, they're easy to read because of that; it's always clear where you stand with an animal.
They also read us and respond accordingly. Animals respond instinctively to people who feel positively toward them, and the positive feelings come out subconsciously in the form of relaxed body language that animals can sense, and even a different smell (the old cliche of "smelling fear" is real). Animals can actually read muscle tone well in other animals including humans, even though we're clothed, because muscle tone transfers into to micro-postures. They can see tense muscle tone in a way we can't in each other or them. If you are relaxed there's a natural attraction and a reciprocating relaxation that gets started.
While I can have cordial and even loving connections to humans, if this suddenly became a world without humans tomorrow, I would be absolutely fine -- as long as there were still animals. I couldn't live without animals in my life. Which is why I think it's brutal and punitive when landlords or property managers and owners have "no pets" clauses. Having an animal to love and care for can be a psychological life saver for some people, but unfortunately one can't always pick and choose a pets-allowed place, for economic reasons and if you live in a city with a crisis housing-wise, as I do. I also think anyone with autism of any level should get to have an emotional support animal if they want to have one. The UK is way behind on this, especially concerning housing and allowing an animal.