It sounds like you're asking about why a real mouse might bite. Here are some possible reasons:
* Fear: Mice are naturally afraid of humans. If they feel threatened or trapped, they may bite as a defense mechanism.
* Protection: A mother mouse will fiercely protect her young. If you get too close to her nest, she might bite.
* Disease: A sick mouse might bite more often due to pain or disorientation.
* Territoriality: Mice are territorial and may bite if they feel their space is being invaded.
If you're concerned about a mouse biting you, it's best to avoid contact with them. If you have a mouse infestation, you should call a professional pest control service to deal with the problem.