We live in Florida in a house that is at least 20 years old. There is a loud snapping sound coming from the attic area several times each hour. The owner who we rent from says he never noticed it and has no clue what it could be. I don't know how he could have helped but notice it. It actually makes me jump when it happens. I asked him if maybe the house was haunted, and he didn't like that. The noise is making me crazy!

Cats, squirrels, birds, mice or rats ? Does it have a automatic exhaust to vent the attic that may be coming on and getting louder ?

Greetings from Sarasota, Let's go through the "could be's"
Could be critters up there. (I had tree rats in my attic years ago.)
Could be a vent stack expanding and contracting against a stud or rafter. **OR**
Could be you rented a haunted house.
Your choice, your pleasure. Cheers, Tom

I am going with expansion of the roof and rafters. Why not grab a flashlight and go sit up there for a few minutes to see if you can narrow down the source.