hmm, ours had railings on the sides that were about a foot long, kept his head in so if his feet fell out he wouldnt fall out completly. although he has fallen out completly a couple of times. I used to move him over right before I went to bed just incase he rolled over in the middle of the night. One time he fell out right on the dog that was sleeping beside his bed, the dog didnt move the entire night. that morning, the poor dog had this look on his face like, Help me please! good thing he is a big german shepard.