Here's why:
* Lack of a lower esophageal sphincter (LES): The LES is a ring of muscle that separates the esophagus from the stomach. It prevents food and acid from backing up into the esophagus. Rats don't have a well-developed LES, making burping impossible.
* Different digestive system: Rat stomachs are designed to digest food quickly and efficiently, with the focus being on breaking down food rather than releasing gases.
While rats can't burp, they do produce gas. However, they release it through their rectum, not their mouth.