Diapers? What are those?

One of the new things I have learned in China is well baby’s do not use diapers very often. I was sitting on the Subway and looked in front of me and this adorable baby boy maybe like 5 months. I looked down and he had pants that were split at the crouch and no diaper. Come to find out they all use those pants, when the baby has to go potty they hold them over the trash can. My question is how they know when they have to go at such a young age where there is not that much communication. I guess diapers are way expensive, if you look all over the sidewalks there is poo everywhere! Little kids run outside of stores and go potty on the side walk next to you WEIRD. That is one of the many things that I am so grateful for in Good Ol’ America. I have learned to look at these things in China and just laugh it off, and be really appreciative of what I have.