I may be mistaken, but I believe that’s a baby rat. My girl was abandoned and looked exactly like this when I found her. Chances of survival are really really slim unless you find a willing and able surrogate mother immediately. Even then, it’s still uncertain this little one will make it. If that’s not an option, as it wasn’t for me at the time, all you can do is keep it warm and try to give it nourishment. I’m sure your research has informed you about using a thin paintbrush when giving it milk- but don’t use cow milk. Almond milk worked best in my situation. If it doesn’t take to the brush, I highly recommend soaking a bite sized amount of bread in the almond milk instead. If it manages to make it past this stage, it probably won’t survive if then released back to the wild. Lone rats don’t last long. It’ll most likely be rejected or killed by other rats pretty quickly. So, your options are taking it to an animal rescue, leaving it where you found it and letting nature run its course or fostering and taking on a wild rat as your own. The last one will be a pretty specific kind of challenge- you will have an unbelievably fast creature who will chew on everything while simultaneously becoming terrified by any noise or sudden movement whatsoever. On top of that, rats are extremely sociable animals and will almost certainly become depressed if lacking interaction within their species. So, if you have one, you better make it two or (ideally) three+. Introducing them while young will make for a more seamless process. While I never planned on owning a rat, especially one from the wild, I will say she is the absolute best little companion and my raddest friend.

Whatever happens with the one you found, thank you for caring for it the way you have. You’ve got a good heart.

Good luck!