I think Crazy Rich makes a pretty good point, in that animals are generally far more easily approachable than people, especially if you're a introvert, and thus can be easier to help. Just like its easier to adopt a puppy or a kitten than it is to adopt a child- not to mention, a lot less paper work and red tape.
Probably why I'll live the rest of days my days with a couple cats and a dog, rather than a significant other.