Platypus (Ornithorhynchus anatinus) Duck-billed platypus eating a worm underwater. (more) What Is a Platypus’s Closest Living Relative? Ask the Chatbot a Question More Actions Share Share Share to social media Facebook X URL https://www.britannica.com/science/What-Is-a-Platypus-s-Closest-Living-Relative Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.

　　External Websites Ask the Chatbot a Question Written by The Editors of Encyclopaedia Britannica 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.... The Editors of Encyclopaedia Britannica Last Updated: Sep 17, 2025 • Article History Table of Contents Table of Contents Ask the Chatbot The closest living relatives of the platypus (Ornithorhynchus anatinus) are the echidnas (family Tachyglossidae), which comprise four species. Both the platypus and the echidnas (or spiny anteaters) are monotremes belonging to the order Monotremata, an ancient group of mammals that are oviparous (egg-laying). The name Monotremata means “one-holed,” in reference to the fact that both sexes have only one opening at the rear of the body, which is used for both reproduction and excretion. In addition to laying eggs, both animals possess electroreceptors, which they use to detect electrical signals in their environments. Despite their shared ancient ancestry and uniqueness ...(100 of 187 words)

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