What is a Kaiju

Kaiju are King Kong inspired and popularized by Godzilla

Kaiju (怪獣 kaijū?) is a Japanese word that literally translates to "strange creature". However, the word kaiju has been translated and defined in English as "monster". Specifically, it is used to refer to a genre of tokusatsu entertainment. Kaiju films usually showcase monsters of any form attacking a major Japanese city or engaging another (or multiple) monsters in battle.

It all starts in 1933, when King Kong was released in the United states. In 1952 it was re-released in Japan inspiring the owner of TOHO studios to produce his own monster movie. This was a post WWII era and the radioactive contamination of the crew of a Japanese fishing boat was fresh on the minds of Japan. In 1954 Godzilla was born with much box-office success. The name Godzilla, originally pronounced  Gojira, is a actually a combination of the Japanese words for Gorilla and Whale. Other notable kaiju include Gamera, Mothra, King Ghidorah, Mechagodzilla and Rodan.

Related terms include kaijū eiga, a film featuring giant monsters and daikaiju, specifically meaning the larger variety of monsters.

Kaiju are typically modeled after conventional animals, insects or mythological creatures; however, there are more exotic examples.

While the term kaiju is used in English to describe monsters from tokusatsu and Japanese folklore,[citation needed] monsters such as vampires, werewolves, Frankenstein's monster, mummies and zombies would fall into this category. In fact, Frankenstein's monster was once a kaiju in the film Frankenstein vs. Baragon, which was created by Toho.

Kaiju are sometimes depicted as cannon fodder serving a greater evil. Some kaiju are elite warriors which serve as the right-hand man to the greater villain and are destroyed by the heroic forces. Others have a neutral alignment, only seeking to destroy buildings and other structures. During the early eras of tokusatsu, "heroic" monsters were rarely seen in daikaiju eiga films, and it was not until later when television tokusatsu productions began using kaiju which aided the hero, saved civilians, or demonstrated some kind of complex personality. These kaiju adopted many classic monster traits, appearing as the "Misunderstood Creature". Some kaiju hung out with the heroes and provided comedy relief, in contrast to the darker approach to these characters from more mature franchises, like Kamen Rider.[citation needed] Godzilla, arguably the most well known of the daikaiju, has played the roles of hero, villain, and force of nature in the course of his existence, one of the few kaiju of any type to be depicted in multiple roles and having those around him react in different ways, depending on how the creature itself was being presented in the films.


The types of Kaiju are limited only to the imagination (and production budgets). Due to their size and unique powers they would create an interesting challenge for a bio-engineer. In a paper titled Towards a Theory and Biology of Kaiju a fan has written an extensive theory based on many of the "scientific research" done in Kaiju movies. Below are the six major attributes of a Kaiju. 

1) They are Unique creatures. The Kaiju are almost all singular creatures, and not species. Only a very few are known to be directly related - the Gargantuas are derived from each other. There may have been a couple of different Godzillas. Rodan was a paired species. Mothra exhibits a life cycle. There may be at least a few Gezoras. But for the rest, Anguirus, Ghidorah, Megalon, Varan, etc., exist as only single creatures. They don't seem to exist in sexes, don't appear to have sex, and don't seem to manifest reproduction or life cycles as we know of them (Mothra being a partial exception).

2) They are taxonomically diverse - King Seesar and King Kong are definitely mammals. Godzilla, Anguirus, Varan, Rodan, etc. are reptiles. Gezora is a mollusk. Kamacuras and Spiega are arthropods. Hedorah is unclassifiable but seems to have been a composite slime mold. Several of the Kaiju seem related to dinosaurs or other Mesozoic animals, but others clearly seem to have roots prior to or after that era.

3) They are structurally identical to animals of various sorts. They have articulated limbs, claws, toes, eyes, mouths, scales, etc. They may be biologically impossible, but in most gross particulars they seem to imitate conventional biological animals closely. They also imitate biological animals in many particulars of behaviour.

4) As noted, their size outstrips any and every biological threshhold.

5) Despite their great size, there's no evidence of normal biology. They don't eat, or when they do it, it isn't nearly in the quanities necessary to sustain their bodies. They don't leave excrement behind. Godzilla and others seem as viable in vaccuum as on land as at the bottom of the ocean, or buried underground - they don't seem to need to breath the way we do.

6) Many exhibit anomalous physical abilities. Godzilla's radioactive breath is only the tip of the icebeg. There's Ghidorah's gravity beams, Rodan's ability to negate gravity, etc. These seem to involve the applications of physics on a nuclear or trans-nuclear scale.

The paper goes on in detail how a Kaiju are created through a type of radioactive fossilization process, instead of organic matter being replaced by minerals, they are replaced by a process happening on an atomic level. In most animals breathing, eating, crapping are part of a chemical process. Kaiju have no need for this because they have an atomic metabolism allowing them to forego many of basic biological function we are familiar with.

Click the following link to read Towards a Theory and Biology of Kaiju in its glorious entirety.