Hamsters squeak in order to express their emotions. These squeaks express happiness, excitement, annoyance and fear. There a number clues that can help determine the specific reason behind a hamster's squeak.
Occasional squeaks are usually not cause for alarm. However, frequent speaks may indicate a problem. Hamsters that squeak persistently might be hungry, thirsty, lonely or injured. Owners should occasionally check cages to make sure they contain adequate food and water. Owners should also make sure that the hamster gets proper socialization and is playing with humans or other hamsters. It is also important to perform a full-body checks to make sure the hamster is not hurt.
If a hamster squeaks after receiving a treat or getting petted, the squeak likely indicates happiness. Hamsters that live together, especially the very sociable dwarf hamsters, might squeak because they like each other and are enjoying the company
A hamster living in a new environment with another hamster for the first time might squeak persistently out of annoyance, and this type of squeaking might also be accompanied by puffing or hissing. Hamsters might also squeak out of fear when their owners handle them roughly. Gently cupping and softly stroking a frightened hamster for a few minutes should alleviate this type of squeaking.