I thought maybe the two dwarf hamsters would like to interact with their own kind occasionally so the hamster pen is put into use again. Hm...this reminds me of the hamster village era long ago.
Maybe it was the new environment, but the hamsters were not interested in each other at first. They were both trying to bite through the playpen instead.
Finally, Potato noticed the presence of a female hamster around, and went over for a look.
Unfortunately for him, Ninja noticed her favourite food in the dish, and ignored him completely.
Anyway, I don't want them to be breeding, so it is best not to let them actually play together. Ninja is too old to be a mother now.