How can tell the difference between a boy and girl hamster?

You can't reliably tell the difference between a boy and girl hamster just by looking at them. Here's why:

* Appearance is very similar: Male and female hamsters look almost identical.

* Genitals are difficult to see: Hamsters are small, and their genitals are located close to the anus. This makes it hard to determine sex by visual inspection alone.

The best way to determine a hamster's sex is through a veterinarian or experienced breeder. They can:

* Examine the hamster's genitals: A vet can carefully examine the hamster's anal region to look for the telltale differences between male and female reproductive organs.

* Perform a palpation: The vet may gently feel the hamster's abdomen to check for the presence of testicles in males.

Warning: Trying to determine sex on your own can be stressful for the hamster and potentially dangerous. It's always best to leave it to the professionals.