She has not been identified or charged.
The boy was killed Saturday morning by what police said was a "bulldog-type breed."
The animal is being held at a kennel while the investigation proceeds.
The incident happened at Tencreek Holiday Park, which is 250 miles (400 kilometers) southwest of London on the coast.
The park said that emergency services were called but the boy was pronounced dead at the scene.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)