We are getting ready to lay the bathroom floor and are going to put a claw foot tub in. I have done floors before but never under a clawfoot. I am thinking there has to be something special I have to do to distribute the weight and using smaller tiles, probably ceramic vs. natural stone? Thanks!

That's the floor that you are laying the tile on? Is it a basement bathroom with existing concrete, or it it on a second floor with a plywood construction floor? Is it a newer house with plywood or is it an older home with floor boards? If it's wood, how thick? Is there any sign of water damage? What are the floor joists like and what is the spacing?

J&D is right about asking a lot of questions. There's a lot of point load under a claw foot tub so your floor system needs to be strong enough for the tile you intend to use.
If the plan is to use a natural stone, the floor system really needs to be brought up to spec for that type of tile.
Natural stone is generally very weak with fissures and veining. This is why the floor needs to be as deflection free as possible. The additional problem of the point loads of the feet compounds this situation.