Penis (plural - penises, or penes) is a general term for the male organ of reproduction. All penises are designed to do the same job – to transfer sperm from a male to a female - but they differ widely in shape, structure and size. In placental mammals the penis is also used to pass urine out of the body.
Many species of animal don’t have a penis at all. Some have more than one. In most reptiles and amphibians the male genitals consist of a cloaca, a hole or slit that is placed against the female genital opening. However, snakes have a Y-shaped hemipenis armed with hooks to get traction on the female. Most birds have cloacas too but ducks and a few other species have a pseudo-penis made from the cloacal wall and erected with lymph rather than blood.
Some fishes have claspers made of two modified fins that grip together to make a tube and octopuses use a specialised arm called the hectocotylus.
Insects have a structure called the aedeagus that is analogous to the penis. Many species use these for so-called ‘traumatic insemination’ where the organ is used to stab a hole in the female rather than use a specialised orifice.
Marsupials have a bifurcated penis that corresponds to the females’ two vaginas (or three vaginas if a kangaroo).
The largest true penis that we know of belongs to the largest animal – the blue whale. It typically measures 8-10 ft (2.4 - 3 m) in length and has a girth of 12-14 ins (30-36 cm). The smallest belongs to the common shrew (0.2 inches or 5 mm). However, penis size isn’t always proportionate to body mass; the average human penis (flaccid) is around 4 ins (10 cm) while a fully grown 500lb bull gorilla can only boast 1-1½ ins.
Meanwhile, the Argentine blue-bill – a species of duck which has a body length of around 15 ins (40 cms) - has been documented with a penis 17 ins (42.5 cm) long.
But the grand prize for longest penis in proportion to body size belongs to the barnacle which has a penis over forty times its own body length. As the animal is immobile, its penis has grown long enough to seek out females anchored nearby. It grows a new penis every time it needs one.
Me, I'm hung like a wet gerbil.
I have a carved walrus penis bone on my desk. It’s two feet long. I find it helpful when it comes to intimidating men.
The hectocotylus of the argonaut – a kind of nautilus – can detach from the animal and go off on its own in search of a mate. For a number of years, people believed it to be a kind of parasitic worm.
The echidna, the egg-laying monotreme also known as the spiny anteater, has a penis with four heads, each capable of delivering sperm. Only two are used when mating while the other two shut down.
Cats have barbed penises that scratch the walls of the vagina upon withdrawal. This action triggers ovulation. Dog penises, meanwhile, have a bulbous glans that swells up during copulation resulting in the two animals becoming stuck together or ‘dog-knotted’. This ensures that the male’s sperm gets to the ovaries before another dog can mate with the female.
The common bed bug, Cimex lectularius, has a sharp penis with which it stabs the female. The male climbs onto the female’s back, his head draped casually over the equivalent of her left shoulder and his body curved around hers in a violent embrace. Then he aims his pointy member not at her genitals, but at the right side her abdomen where he stabs her, ejaculating directly into her body cavity. This is called traumatic insemination.
Most placental mammals have a penis bone called the os penis or baculum. The name has its origin in the Latin for ‘stick’ or ‘staff’. The wide distribution among species suggests that the bone evolved early in the history of mammals and was subsequently lost in certain groups. Among the mammals that don’t have them are marsupials, monotremes, horses, rabbits, elephants, whales, hyenas and humans.
The marmoset has a baculum measuring around 2mm and the tiny 63g Galago, also known as the bush baby, has one around 13mm long. The Great Apes, despite their size, tend to have small penis bones.
The walrus has a particularly large baculum – around two feet long - and native Alaskans call it an oosik. The Chukshi people, who live in a large area from the Bering Strait to the Kolyma River valley in inland Siberia, produce beautifully carved and decorated oosiks that used to have totemic significance in their shamanistic religion. These days, they are sold to tourists. In 2007, the largest known fossilised penis bone (from an extinct walrus) sold for $8,000 at an auction in Beverly Hills. It was 4½ ft long and was bought by Ripley’s Believe It Or Not.
Correspondingly, in females there is a tiny clitoral bone called the baubellum or os clitoridis.
In Chinese medicine, deer penis is supposed to increase strength and is touted as an effective remedy for athletic injuries. It was therefore listed as a banned substance during the 2008 Summer Olympics in Beijing.
The Icelandic Phallological Museum in the fishing town of Husavik proudly boasts a collection of penises from many different species. In 2011 it acquired its first human exhibit, the severed and preserved organ of 95-year-old Pall Arason.
Highlights of the museum's collection include a 67 inch (170 cm) sperm whale penis and lampshades made from bulls’ testicles.
The menu of the Guo Li Zhuang Restaurant in Beijing lists delicious sounding dishes such as ‘The Essence of the Golden Buddha’, ‘Phoenix Rising’ and ‘Jasmine Flowers with 1,000 Layers’ but all of them are made from animal genitals. Each type of penis allegedly has properties that the diner will inherit. Among the most expensive dishes are yak penis ($220), the 10 assorted penises plate ($110) and, at over $1,500, tiger penis which has to be ordered several months in advance. The restaurant is on Dongsishitiao Street.
Male Guinea baboons ritualised greeting involves fiddling with each other's genitals.
An iguana in Aquatopia Zoo, Antwerp, named Mozart, was found to have a permanent erection six days after a mating session.
A barnacle can change the length of its penis to take advantage of local wave conditions.
In South Korea, dogs' penises are highly prized as an aphrodisiac.
Hans Christian Andersen was convinced that his addiction to masturbation would lead to his penis falling off.
530 British men attended casualty in 1999 following eye-watering encounters with their zips.
The male nine-banded armadillo can scratch its chin with the end of its penis.
Chinese surgeon, Doctor Long, was the inventor of the modern penis extension.
In Thailand, over 200 cases of severed penises are reported every year.