# What mammal has the largest testicles compared to its overall body size? **URL:** \ **Category:** Factual Questions\ **Created:** [August 23, 2006, 11:06pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959 "2006-08-23T23:06:07Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [August 23, 2006, 11:06pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/1 "2006-08-23T23:06:07Z")
Just curious. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [August 23, 2006, 11:11pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/2 "2006-08-23T23:11:36Z")
I don’t know if they are the largest, but I saw an article years back about a largish monkey that competes among themselves largely with sexual endurance contests. They had scrotums that were nearly as big as their head IIRC. ---
**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:** [August 23, 2006, 11:38pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/3 "2006-08-23T23:38:52Z")
The mammal with the largest testes in absolute size is the Right Whale, in which they can weigh 500 kg each. That is, however, only about 1% of body weight. ---
**Author:** ![Valgard](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Valgard](https://boards.straightdope.com/u/Valgard)\ **Post date:** [August 23, 2006, 11:42pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/4 "2006-08-23T23:42:54Z")
> [@Der Trihs](#): > > I don’t know if they are the largest, but I saw an article years back about a largish monkey that competes among themselves largely with sexual endurance contests. They had scrotums that were nearly as big as their head IIRC. Bonobos, perhaps? > **[Bonobo](https://en.wikipedia.org/wiki/Bonobo)** > > The bonobo (/bəˈnoʊboʊ, ˈbɒnəboʊ/; Pan paniscus), also historically called the pygmy chimpanzee (less often the dwarf chimpanzee or gracile chimpanzee), is an endangered great ape and one of the two species making up the genus Pan (the other being the common chimpanzee, Pan troglodytes). While bonobos are, today, recognized as a distinct species in their own right, they were initially thought to be a subspecies of Pan troglodytes, due to the physical similarities between the two species. Taxon... ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [August 23, 2006, 11:43pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/5 "2006-08-23T23:43:02Z")
[Why are rat testicles so big?](http://www.ratbehavior.org/testicles.htm) > [@](#): > > Species in which multiple males mate with a female in a short span of time encounter sperm competition and have large testicles relative to their body size. Species in which just one male mates with a female encounter no sperm competition and have relatively small testicles. Someone’s done a nice graph of testicle size vs mass for different species, but I’m not finding it on the internet tonight. ---
**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\ **Post date:** [August 23, 2006, 11:45pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/6 "2006-08-23T23:45:04Z")
Are you looking for a whole species or just an individual? I can’t help you on the former but I am pretty sure I know the latter especially when I was skinnier. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [August 23, 2006, 11:45pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/7 "2006-08-23T23:45:28Z")
> [@Valgard](#): > > Bonobos, perhaps? > > [Bonobo - Wikipedia](http://en.wikipedia.org/wiki/Bonobo) No, they were tree living moneys, not apes. ---
**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\ **Post date:** [August 23, 2006, 11:45pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/8 "2006-08-23T23:45:50Z")
[This little feller’s doin’ pretty good.](http://www.vul.bc.ca/v3/team/pictures/squirrel_nuts.jpg) ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [August 23, 2006, 11:48pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/9 "2006-08-23T23:48:45Z")
Mice are well endowed in that department; I don´t know if their weight to family jewlery ratio is the best around, but it has to be close. In any case, and as a WAG I´d look into the rodents branch for the winner. ---
**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:** [August 23, 2006, 11:51pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/10 "2006-08-23T23:51:16Z")
At least one bat, Rafinesque’s Big-eared Bat, has testes that amount to 8.4% of its body weight. Research on bats has indicated an inverse correlation between testes size and brain size: [Bigger balls means smaller brains.](http://news.mongabay.com/2005/1213-bats.html) This relationship does not hold across taxa however; among our closest relatives, chimps (and I assume bonobos) have the largest testes, gorillas the smallest, while humans are intermediate. ---
**Author:** ![Freddy\_the\_Pig](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@Freddy\_the\_Pig](https://boards.straightdope.com/u/Freddy_the_Pig)\ **Post date:** [August 24, 2006, 3:46am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/11 "2006-08-24T03:46:07Z")
> [@Colibri](#): > > At least one bat, Rafinesque’s Big-eared Bat, has testes that amount to 8.4% of its body weight. Criminy! That would be like . . . well, I guess we can all do the math. Dare I ask, are these bats also well endowed in the schlong department? ---
**Author:** ![Schuyler](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@Schuyler](https://boards.straightdope.com/u/Schuyler)\ **Post date:** [August 24, 2006, 6:40am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/12 "2006-08-24T06:40:06Z")
Well, if you were really interested in relative testicle size in primates, might I point you to the following paper by Adolph Schultz, “[The relative weight of the testes in primates](http://www3.interscience.wiley.com/cgi-bin/fulltext/109892692/PDFSTART)” [warning pdf] - from 1938! This just came up in Google, believe it or not. Anyway, maybe someone more knowledgeable than I can comment on the validity of the findings, but the author describes his examination of upwards of 80 small and large, new and old world primates, and humans. He finds that macaques have the largest relative testicle size (noting that an 8kg bonnet macaque had testes larger than a 69kg man); among the large primates, chimps had the relatively largest testes, and gorillas seemingly the smallest. Hope that helps. ---
**Author:** ![shizaru](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@shizaru](https://boards.straightdope.com/u/shizaru)\ **Post date:** [August 24, 2006, 6:41am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/13 "2006-08-24T06:41:23Z")
[QUOTE=astro] Just curious. [/QUOTE] Jack Bauer ---
**Author:** ![shizaru](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@shizaru](https://boards.straightdope.com/u/shizaru)\ **Post date:** [August 24, 2006, 9:43am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/14 "2006-08-24T09:43:19Z")
I was wrong, its not Jack Bauer, the title goes to the [Lonk.](http://www.sheep101.info/Images/Breeds/Lonk.jpg) You can find out what a lonk is on this [thread.](http://boards.straightdope.com/sdmb/showthread.php?t=385303) ---
**Author:** ![Dottygumdrop](https://avatars.discourse-cdn.com/v4/letter/d/ce73a5/32.png) [@Dottygumdrop](https://boards.straightdope.com/u/Dottygumdrop)\ **Post date:** [August 24, 2006, 10:04am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/15 "2006-08-24T10:04:25Z")
[Scylla’s goat](http://boards.straightdope.com/sdmb/showthread.php?t=33909&highlight=goat)! ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [August 24, 2006, 10:35am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/16 "2006-08-24T10:35:15Z")
“Then the goat hit puberrty…” One of the all-time great SDMB lines. ---
**Author:** ![shizaru](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@shizaru](https://boards.straightdope.com/u/shizaru)\ **Post date:** [August 24, 2006, 10:39am UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/17 "2006-08-24T10:39:31Z")
[QUOTE=Dottygumdrop] [Scylla’s goat](http://boards.straightdope.com/sdmb/showthread.php?t=33909&highlight=goat)! [/QUOTE] **That. was. fucking. _hilarious_!!!** I had to go to the restroom so people wouldn’t see me at my desl laughing like a maniac! ---
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [August 24, 2006, 2:10pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/18 "2006-08-24T14:10:33Z")
[QUOTE=shizaru] Jack Bauer [/QUOTE] Of course, by “Jack Bauer” you mean “Chuck Norris.” ---
**Author:** ![Cockatiel](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Cockatiel](https://boards.straightdope.com/u/Cockatiel)\ **Post date:** [August 24, 2006, 4:06pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/19 "2006-08-24T16:06:50Z")
[Tanuki?](http://en.wikipedia.org/wiki/Tanuki) ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [August 24, 2006, 4:22pm UTC](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959/20 "2006-08-24T16:22:40Z")
Well [I’ve got big balls](http://users.bart.nl/~ljmeijer/oldham/lyrics/balls.htm) 😃 [Next page](https://boards.straightdope.com/t/what-mammal-has-the-largest-testicles-compared-to-its-overall-body-size/369959.md?page=2)