I want to see those squirrels they eat. Very few animals survived but the squirrels are common fare. Must be ground squirrel since there's no more trees and grounds squirrels would have burrows to protect them from a lot of the radiation. They're probably small as we don't emcounter them as we do mole rats. They either spend a good deal of time underground to avoid the preds we and probably make up a large portion of their diet as there aren't enough humans to eat. I'd like to think they're either big squirrels or their cousins ground hogs who are more like badgers or small wolverines to face the Wasteland.
We also know Wastelanders eat iguana. Iguana aren't native to the east coast . They're either misnamed indigenous animals or escaped pets, not too much a stretch consitering how popular and common they are in our world. The Wasteland seems to be a warm, dry climate so certain iguanas could be at home. As with the squirrels they may be small but vicious and also burrowers.
Let's see, we have bears and mole rats and imported scorpions. I would love to see (from a distance) mutated bobcats and cougars! A cougar the size of a tiger that hunts deathclaws! A direcat.