you are likely to find Pig in/at/on Mud. Mud is a type of River. River is the opposite of Land. 
Big is related to Man. Man is related to Body. Body is related to Government. Government is related to Congress. 
Pig --AtLocation--> Mud --IsA--> River <--Antonym--> Land 
Big <--RelatedTo--> Man <--RelatedTo--> Body <--RelatedTo--> Government <--RelatedTo--> Congress 