He isn't neutered. If he was, they'd look like shriveled up grapes.
Depending on how old he is, neutering him might not change some of his behaviors. It's a hit or miss. Some dogs' behavior changes after, but the older they get, the more habits they keep. The male aggression is a more of a training issue rather than hormonal. The humping though, that can be attributed to the fact that he's intact.
If he isn't neutered, I strongly encourage you to have him neutered. No reason in the world to keep an intact dog if you're not a breed enthusiast who shows and breeds their dogs. That's how accidents happen and I'm sure you're aware of the dog over population problem.
But really, the shelter you got him from should be paying for his neutering especially if you entered into a contract that promised he'd be fixed.
