If it's any consolation, no one told me either when I got the first one 35 years ago...
BTW, rat snakes are great climbers & lots of fun to watch when you put branches in their tanks. (IMO glass tanks work best, w/ screen tops
for good ventilation). I just cut branches to fit diagonally (with a small jig saw) & criss-cross them in the middle (so they're wedged in place)
..these snakes are so graceful on branches.