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Can You Guess Which Of These Animals Has The Biggest Penis?

That's one big duck.

How well do you know your animal kingdom anatomy? Order these animals by their penis size — longest first!


Oh and just in case you were's a Sperm Whale's todger.

A Barnacle releasing his beast.

And of course a duck, horrifying us all with its corkscrew cock.

Please forgive me for what your eyes can now, never unsee.


Nature's Nether Regions: What the Sex Lives of Bugs, Birds, and Beasts Tell Us About Evolution, Biodiversity, and Ourselves (Penguin Group, 2014) By Menno Schilthuizen

Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15 521 men (BJU International, 2004) By David Veale, Sarah Miles, Sally Bramley, Gordon Muir and John Hodsoll

Equine Reproductive Physiology, Breeding and Stud Management, (Cambridge University Press) By Mina C. G Davies Morel

Male Reproductive Dysfunction (Jaypee Brothers Medical Publishers, 2011) By SC Basu

Pheromones and Animal Behavior: Chemical Signals and Signatures (Cambridge University Press, 2014) By Tristram D. Wyatt

Sperm Competition in Humans: Classic and Contemporary Readings (Springer Science + Business Media, Inc, 2006) By Todd K. Shackelford, Nicholas Pound

Dr Alexander Arkhipkin tells the BBC

Arctic Animals and Their Adaptations to Life on the Edge (Tapir Academic Press, 2005) By Arnoldus Schytte Blix

Wild Mammals of North America: Biology, Management, and Conservation (The John Hopkins University Press, 2003) By George A. Feldhamer, Bruce C. Thompson, Joseph A. Chapman

Mammal Anatomy: An Illustrated Guide (Marshall Cavendish Corporation, 2011) By Marshall Cavendish Corporation