However, thanks to evolution, some species have come up with some really remarkable and weird innovations in penis design. So, let's see some of the world's weirdest wieners!
1. The gigantic penis
You have probably heard the joke about elephants or donkeys having a fifth leg. The truth is that relative to their body size, barnacles are the clear winners. Due to their immobile lifestyle, barnacles have evolved to have remarkably long penises [up to 40 times their body-length] to ensure genetic transfer between isolated individuals.
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See that long-fillament? Guess what it is! Credit: Chris Neufeld |
As for more complex and everyday animals, the gold medal goes to the Argentine lake duck (Oxyura vittata) which has a penis that when erect can be as long as the animal itself. This is even more surprising considering that most male birds have no penis at all! The best endowed lake duck ever found had a 42.5 cm long erect penis.
Credit: K McCracken/ Nature |
Extra Fact: Male ducks have corkscrew-shaped penises cause female ducks have corkscrew-shaped vaginas
2. The Four Headed Penis
Along with the platypus, echidnas are the only surviving monotremes. The echidna is a weird animal for many reasons. It looks like a cross between a hedgehog, a platypus and an anteater, it has electroreception and it lays eggs despite its mammalian nature. Oh, yes! It also has a 4-headed-penis:
Jump to 00:17 for the kinky part
3. The Singing Penis
The lesser water boatman (Micronecta scholtzi) is a tiny 2 mm long insect found in freshwater ponds and lakes across Europe. In 2011, researchers made an unexpected discovery. Males produce their underwater courtship song by rubbing their penis along their ribbed abdomen. But what is more interesting is that this sound can be up to 99.2 decibels loud, a volume comparable to a passing freight train.![]() |
Micronecta scholtzi |
Although most volume is lost when sound moves from water to air, it still remains audible to humans walking along the pond shore. For its size the M. scholtzi is considered the loudest of all animals.
4. The Double Penis
Male squamates (snakes, lizards and worm lizards) have a sexual organ called hemipenes. This is essentially a pair of two weird looking penises that come in a variety of shapes and sizes, depending on species. Often, the hemipenis bears spines or hooks, in order to securely anchor the male inside the female. Some species even come with a forked hemipenes (each hemipenis has two tips).
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The hemipenis of a rattlesnake Credit: Tess Thornton |
5. The Piercing Penis (Traumatic insemination)
Traumatic insemination (or hypodermic insemination) is the mating practice of some invertebrates in which the male uses its penis to pierce the female's abdomen to inject his sperm through the wound into her abdominal cavity. Not surprisingly, the process is dentrimental [and sometimes lethal] to the female's health as it creates an open wound.
A prime example of traumatic insemination are bed bugs which reproduce solely using this method.
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A male bed bug (Cimex lectularius) traumatically inseminates a female bed bug (top). Credit: Rickard Ignell |
Like most octopuses, the argonaut octopus, a type of nautilus, has a rounded body, eight arms and no fins. But it also has a detachable penis! Yep, you read that correctly. The males use a modified arm, called the hectocotylus, to transfer sperm to the female.
During fertilization, the arm is first inserted into the female's pallial cavity and is then detached from the male. Obviously, males mate only once in their life.
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Male argonaut (left) and argonaut penis (right) Source |
Fun Fact: The hectocotylus when found in females was originally thought to be a parasitic worm.
7. The Female Penis
The rule is, males have penises, females have vaginas. Or something like that. But every rule has an exception. The exception to this rule is Neotrogla, a genus of barklice noted for its reversed sex roles and organs, traits shared by all species of the genus.
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N. curvet mating (female on top) |
Female Neotrogla possess a penis-like organ, called "gynosome", whereas males have a small, vagina-like opening. During mating, the female mounts the male and penetrates his small genital opening from behind. With her gynosome she extracts sperm and nutrient-filled seminal fluid from the male.
Fun Fact: A single mating session can last from 40 to 70 hours!
Finally we have the genitalia of female spotted hyenas. Elevated levels of testosterone cause the females to develop a penis like thing, called pseudo-penis. This appendage is essentially an enlarged clitoris capable of erection that can grow as long as 7 inches.
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Female Hyeana Pseudopenis Credit: National Geographic |
Do you know of any other examples of weird animal penises? Shoot them up in the comments!
- "Biology of Barnacles". Museum Victoria. 1996. Archived from the original on February 17, 2007. Retrieved April 20, 2012.
- McCracken, K. (2000). The 20-cm Spiny Penis of the Argentine Lake Duck (Oxyura vittata) The Auk, 117 (3) DOI: 10.1642/0004-8038(2000)117[0820:TCSPOT]2.0.CO;2
- Sueur, J., Mackie, D., & Windmill, J. (2011). So Small, So Loud: Extremely High Sound Pressure Level from a Pygmy Aquatic Insect (Corixidae, Micronectinae) PLoS ONE, 6 (6) DOI: 10.1371/journal.pone.0021089
- Yoshizawa, K., Ferreira, R., Kamimura, Y., & Lienhard, C. (2014). Female Penis, Male Vagina, and Their Correlated Evolution in a Cave Insect Current Biology, 24 (9), 1006-1010 DOI: 10.1016/j.cub.2014.03.022
- Engh, A., Van Horn, R., Szykman, M., Holekamp, K., & Boydston, E. (2007). Courtship and mating in free-living spotted hyenas Behaviour, 144 (7), 815-846 DOI: 10.1163/156853907781476418
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