>>13274177//Partner bonding, from easiest to harder:
Guinea pigs
Chinchillas
Rats
Mice
Hamsters
Gerbils (strictly monogamous, 1 partner forever, impossible bonding when adults because they have a “fixed marriage ceremony” when they are 1 month old, yes it’s real)
Hamsters are hard to bond, but possible if you use a fence to separate each other in the same cage for at least 28 days.