Among the most recognizable and ribald images in Japanese folk art is a rotund, jolly little bear-like animal, wearing a large straw hat and carrying a bottle of sake, and most unabashedly propped on top of his own enormous, dragging scrotum. This is the famous and beloved tanuki, sometimes called the "raccoon" of Japan.
The tanuki is in fact not a raccoon at all, but rather an odd member of the dog family that resembles that exclusively North American animal. Commonly called a "raccoon dog" in English, Nyctereuctes procyonoides is easily distinguished by lacking its look- alike's tail rings, and walking on its toes like a dog.
In folklore the tanuki is a bit like the plump, comical brother of the fox, equally prone to mischief and shape-changing and the deception of humans. Often considered the same animal as the mujina, it is blamed for all sorts of ghostly occurences. It seems to have a hedonistic bent, constantly on the prowl for saké, food, and women, and is known to disguise worthless leaves as money to obtain those things. It also seems quite good at turning itself into inanimate objects, such as the tea-kettle in the famous story of the Bunbukuchagama.
Of course the most infamous aspect of the tanuki's shapeshifting involves its testicles. By blowing air and pulling, the male raccoon dog can stretch his scrotum into a vast sheet exceeding eight tatami mats in size. Sometimes only exceptionally clever tanuki called mamedanuki are said to be able to do this. The tanuki in comic art is portrayed employing his expanded testicles in numerous ways - he may use them as a raincoat or a blanket, a boat or a blunt weapon, he may disguise them as another yokai such as a rokuro-kubi or a tengu in order to frighten his fellow raccoon dogs, or he may even traipse through a landscape made up entirely of hairy, wrinkled scrotal skin. The mame-danuki in particular is said to transform its testicular expanse into rooms and invite humans in to do business, but often a lit cigarette dropped on the "floor" will break the illusion and send the revealed animal fleeing and yelping in pain.
The tanuki is also said to be fond of coming out at dusk and drumming on its plump belly and distended kin-tama ("golden balls"), filling the night air with the deep hollow sound of pon-poko-pon.
It is worth noting the raccoon dog's testicles are a motif unrelated to sexuality or fertility, and instead are merely a symbol of good luck and an element of silly, earthy, risqué humor.
And while it is often seen as comical, the tanuki has a brash, violent, even morbid side as well. The popular tale Kachi-kachi-yama, or "Click Clack Mountain" features a wicked raccoon dog who kills an old woman, tricks her husband into eating her flesh, and is tormented and finally vanguished by a rabbit seeking vengeance for her human friend.
The tanuki of Shikoku seem especially prone to going to war. In Ehime prefecture an audacious tanuki named Inugami-gyobu had a band of eight hundred and eight followers, and layed plans to capture Matsuyama Castle, but the tanuki were all defeated and sealed up in a cave by a hero wielding a magic wooden hammer. Another famous tanuki battle took place in Tokushima prefecture, when the tanuki hero Kincho got into a feud with his tanuki mentor Rokuemon, and all the raccoon dogs in the area wound up participating in the fight. In the end Rokuemon was defeated and Kincho died from his wounds, but a human friend of Kincho's erected a shrine in his honor which is still visited today.
Sometimes called a racoon-dog, the tanuki is a beloved Japanese animal, and appears sporadically throughout the series in the form of Miroku's not-so-loyal sidekick, Hatchiemon.