Due to your ratness, you got a good sniffer. You have advantage on Wisdom (Perception) checks that rely on smell. 

Due to your ratness you have good teamwork skills. You have advantage on an attack rolls against a creature if at least one of your allies is within 5 feet of the creature and the ally isn't incapacitated.

Due to your ratness you have no thumbs. You cannot wield weapons or dawn armor, unless it is specially made for you. You can still hold objects however, and are capable of using most magic items that aren't armor or weapons. 

Due to your ratness you can see good in the dark. You have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

Due to your ratness you have some good chompers. Your sharp incisors serve as a natural weapon, which you can use to make unarmed strikes. If you hit with it, you deal piercing damage equal to 1d4 + your Dexterity modifier, instead of the bludgeoning damage normal for an unarmed strike.

Due to your ratness you're kinda fast and smart, but you're not that strong. Your Dexterity, Wisdom, and Intelligence increase by 1. Your Strength decreases by 2. 

Due to your ratness you can talk to other animals. You can cast the spell Speak With Animals at will as an action. 

Due to your ratness you don't get anything for this. You know one language.