Mice can squeese though the bars.
Mabye hamsters, a bit boring but mabye.
I was going to get some zebra finchs and i have done some reasch on them.
Guine pigs mabye?
I will tell you the dimensions tomorrow.
guinea pigs would be about all, i would assume it is to small for chinchillas, , esp if you are interested in breeding them, I think it may have to may options for hamsters to escape, ..
Guinea pigs like to have a lot of horizontal floor space. Chinchillas like to have vertical space. The cage looks a little small for either. Bar spacing might be too big for a hamster, almost certainly too big for mice. Don't know enough about gerbils and degus (and their sizes) to comment. Even if ferrets weren't illegal, the cage looks too small for them. Why not go with rats again?
As one vet who treats sugar gliders said, "it's hard to recreate the forests of Australia in your living room." i.e., sugar gliders need a lot of room. and variety of food that doesn't really exist in captivity.