Cloaca | Anatomy | Britannica

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External Websites

• Verywell Health - An Overview of Cloacal Exstrophy
• Cleveland Clinic - Cloacal Malformations
• National Center for Biotechnology Information - PubMed Central - Challenges in the Prenatal Diagnosis of Cloaca
• Medscape - Cloacal Malformations
• eCommons at AKU - Diagnosis and management of the neonatal cloaca (PDF)
• Children's Hospital Colorado - Cloaca
• Frontiers - Frontiers in Pediatrics - Cloacal Malformations: Technical Aspects of the Reconstruction and Factors Which Predict Surgical Complexity

cloaca anatomy Ask Anything Homework Help Written and fact-checked by Britannica Editors Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree.... Britannica Editors Last updated Feb. 23, 2026 •History Britannica AI Ask Anything Table of Contents Table of Contents Ask Anything

cloaca, (Latin: “sewer”), in vertebrates, common chamber and outlet into which the intestinal, urinary, and genital tracts open. It is present in amphibians, reptiles, birds, elasmobranch fishes (such as sharks), and monotremes. A cloaca is not present in placental mammals or in most bony fishes. Certain animals have, within the cloaca, an accessory organ (penis) that is used to direct the sperm into the female’s cloaca. This structure occurs in many reptiles and in a few birds, including ducks. Most birds, however, mate by joining their cloacas in a “cloacal kiss”; muscular contractions transfer the sperm from the male to female.