* Copulation plug is small and lies deep in the [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology|vagina]], so cannot easily be detected. | * Copulation plug is small and lies deep in the [[Female_Reproductive_Tract_-The_Vagina/Vestibule_- Anatomy & Physiology|vagina]], so cannot easily be detected. |