Like everywhere also here in the outside of Biosphere2 there are rattle snakes. We were warned by the guide and I just want to pass the warning further to you. Myself I haven't seen any during the whole trip through the Southwest of the States.
But to make it clear: There are NO snakes inside!
This huge "Biosphere 2" is set in the middle of nowhere in Oracle, Arizona. The University of Arizona spent over 150 million dollars to build it --- but the natural habitat remains the same around it to maintain the ecosystem of the desert. So, sometimes it has unexpected visitors like huge bees we saw flying around, huge ants on the ground that the twins followed around, and finally a SNAKE!
We were following our guide (who was also named Norm) outside the Biosphere as we were heading to the aquarium when he suddenly stopped! My son was just behind him and he pointed to the paved floor -- there was a snake matching the design of the floor! I would have missed it --- I think it was a rattlesnake and I asked Norm if it was poisonous and he said, "Yes". Yikes - that's nice to know!
Thank God my son followed directions and just stayed right behind the guide and not ahead of him - otherwise my son would have stepped on the snake!
Much of the area around Oracle, and indeed throughout Arizona, is open range. Don't be surprised if you have to share the road with this fellow. Use Caution.