Well, to be honest, I wouldn't be able to tell if they actually mated, but she was less than 50 yards/meters away from where we released him, so it is possible. They aren't that rare around here as we see them most summers. In fact, we found another one a couple of weeks before, but it was dead when we found it. They usually live in the forrest and eat dead and decaying trees or fallen fruit. We have some wild berries around here so I'm sure they eat that too.
It was a great experience and I'm glad to have been able to learn about the Hercules Beetle along with my son. Thanks for the comment!
It does seem very likely that they found each other! I imagine that they have some sort of pheromones for that?