# Which Species Has The Largest Penis? **URL:** \ **Category:** Factual Questions\ **Created:** [March 17, 2004, 4:29pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862 "2004-03-17T16:29:43Z")\ **Posts on this page:** 13\ **Page:** 3
**Author:** ![cwthree](https://avatars.discourse-cdn.com/v4/letter/c/9de0a6/32.png) [@cwthree](https://boards.straightdope.com/u/cwthree)\ **Post date:** [July 16, 2016, 8:51pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/41 "2016-07-16T20:51:26Z")
> [@Colibri](#): > > Right. Ducks and other waterfowl, large flightless birds (ostriches and such), and one kind of weaver-finch, are pretty much the only birds to have a penis. (Ironically, a cock doesn’t have a cock.) To make it more interesting, in birds that have such an organ, the mechanism by which it becomes erect is not the same as the mechanism by which a mammal’s penis becomes erect. For this reason, some biologists suggest that “penis” be used to describe only the mammal’s organ (paired corpora cavernosa that inflate with blood, and an internal urethra) and “phallus” be used to describe what ducks, etc. have (lymphatic cavities and no internal urethra). Also, a duck’s penis isn’t always that big. It grows as mating season approaches, and shrinks dramatically when the season ends. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 16, 2016, 9:11pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/42 "2016-07-16T21:11:27Z")
What do you mean, “the mechanism by which a mammal’s penis becomes erect”? Mammals use at least two different such mechanisms. ---
**Author:** ![Teuton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/teuton/32/3864_2.png) [@Teuton](https://boards.straightdope.com/u/Teuton)\ **Post date:** [July 16, 2016, 9:42pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/43 "2016-07-16T21:42:05Z")
> [@AskNott](#): > > and the barstools, well…] Moby’s Dick! ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [July 16, 2016, 9:49pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/44 "2016-07-16T21:49:57Z")
> [@Chronos](#): > > What do you mean, “the mechanism by which a mammal’s penis becomes erect”? Mammals use at least two different such mechanisms. [Flaccid-to-erect penises (almost) unique in humans?](http://boards.straightdope.com/sdmb/showthread.php?t=545949) ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 16, 2016, 10:03pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/45 "2016-07-16T22:03:31Z")
> [@Chronos](#): > > What do you mean, “the mechanism by which a mammal’s penis becomes erect”? Mammals use at least two different such mechanisms. Can you explain what distinction you are making between mechanisms? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 17, 2016, 1:22am UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/46 "2016-07-17T01:22:39Z")
Some mammals have a baculum, a bone which maintains stiffness of the penis. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 17, 2016, 5:23am UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/47 "2016-07-17T05:23:01Z")
> [@Chronos](#): > > Some mammals have a baculum, a bone which maintains stiffness of the penis. But a full erection is still produced by engorging the penis with blood. It’s not a fundamentally different mechanism. Bird penises are different because the erection is produced by engorging it with lymph. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [July 17, 2016, 5:33am UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/48 "2016-07-17T05:33:23Z")
> [@Surreal](#): > > Which species of animal has the largest penis? Donald Trump? ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [July 17, 2016, 7:27am UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/49 "2016-07-17T07:27:55Z")
> [@Siam\_Sam](#): > > Donald Trump? “Has”, not “is”. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [July 17, 2016, 2:43pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/50 "2016-07-17T14:43:57Z")
Oh. Never mind. :o ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [July 17, 2016, 3:42pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/51 "2016-07-17T15:42:16Z")
**Moderator Note** > [@Siam\_Sam](#): > > Donald Trump? Let’'s keep the political pot-shots out of GQ, please. No warning issued. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [July 17, 2016, 3:52pm UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/52 "2016-07-17T15:52:01Z")
> [@Alessan](#): > > “Has”, not “is”. Ditto on this one. No political pot-shots in GQ. ---
**Author:** ![Siam\_Sam](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Siam\_Sam](https://boards.straightdope.com/u/Siam_Sam)\ **Post date:** [July 18, 2016, 6:29am UTC](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862/53 "2016-07-18T06:29:35Z")
Ah, sorry. Sometimes I can’t keep track of which forum I’m in. My first post wasn’t meant to be political, I would have named anyone claiming a big penis. But I’ll try to be more careful. [Previous page](https://boards.straightdope.com/t/which-species-has-the-largest-penis/234862.md?page=2)