Pikmin are a plant-animal species, first discovered by Captain Olimar when he got stranded on their planet in the first game. The Pikmin are loyal to Olimar whenever he comes, and he may have taught them some degree of survival, considering they weren't extinct in Pikmin 2. They come in many colors, which state their attributes to the environment.
Theories About Creation Of Pikmin
This section is currently speculation.
A theory about how Pikmin were created is that when humans had drove themselves to extinction or maybe have flew to another planet or space station via spacecraft and the remnants of nuclear warheads fused animal with plant. Bulborbs for example move and feed upon other animals and create a society similar to the ant which is an animal trait, however they take the shape of bulbs and may possibly draw sunlight, a plant trait. There were also creatures that resembled leaves in Pikmin 2. Also see Theory of Pikmin Evolution.
It should be noted nothing in the game has yet suggested Humans to be extinct or absent from the planet, to the contrary the landscaping taking place at the Perplexing Pool and influx of human 'treasures' would suggest a recent arrival of humans to the area. It may simply be that the locality Olimar crash lands in has until recently been isolated from contact with Humans and the wildlife has evolved alongside normal Earth life. In the second game rather than explore more of the planet he returns to where he originally landed rather than risk a long search for Pikmin.
Red Pikmin
See main article, Red Pikmin
Red Pikmin were the first species of Pikmin discovered. Their unique physical appearance is their pointed noses. These Pikmin are fireproof, and have slightly higher strength than the other Pikmin, except for Purple Pikmin.
Yellow Pikmin
See main article, Yellow Pikmin
Yellow Pikmin have large ears. They are lighter than the other Pikmin, and they were recently discovered (in Pikmin 2) to be shockproof. They used to be able to carry and throw bomb-rocks, but in Pikmin 2, they have lost this ability. Now bomb-rocks are much larger, which may mean that they are too heavy to be carried.
Blue Pikmin
See main article, Blue Pikmin
Blue Pikmin have what appear to be mouths, but are actually gills. These Pikmin, unlike the others, can survive in water and are resistant to water-based attacks. If thrown into water with drowning Pikmin, they are known to throw the drowners to land.
White Pikmin
See main article, White Pikmin
White Pikmin are smaller than normal Pikmin and have red eyes. These Pikmin are resistant to poison, and also damage enemies that eat them. Their red eyes allow them to detect things buried underground. These Pikmin are also the fastest, and carry objects much quicker than other Pikmin. These Pikmin can only be obtained by throwing other Pikmin into Ivory Candypop Buds.
Purple Pikmin
See main article, Purple Pikmin
Purple Pikmin are bulkier and larger than normal Pikmin and have several wiry hairs growing out of their head. These Pikmin can cause damage simply by being tossed on enemies (which may also stun enemies), and will actually scoot their bodies in the air to try and land directly on the enemy if not tossed directly above it. They can also pick up objects with the force of 10 Pikmin, but move more slowly, even at the flower stage. Like the White Pikmin, they can only be obtained via certain Candypop Buds, which are the violet ones.
Other Pikmin
Mushroom Pikmin
See main article, Mushroom Pikmin
When affected by the spores of a Puffstool, the Pikmin grow mushrooms on their heads and start to attack Olimar. The effect wears off when time runs out or the Puffstool is destroyed. They are found only in Pikmin 1, like the Puffstool.
Bulbmin
See main article, Bulbmin
These peculiar Pikmin resemble Bulborbs with leaves, like a Pikmin, that were apparently controlled by a parasitic Pikmin, with the Bulborb as its unfortunate host. The parasite (Pikmin) controls the Bulbmin's every move, except for the Bulborb's voracious appetite, meaning the Bulbmin will eat any Pikmin without question, even other Bulbmin (under your command). Juvenile Bulbmin are seen following the adults and when the adult is defeated, the Bulbmin wil run around and panic ceaselessly unless you come in and gain their attention. Bulbmin can be controlled by your pilots once their parent is dead. They are immune to every hazard (excluding explosions). However, they don't have some of the primary colored Pikmin's powers (i.e. The ability to be thrown very high, save drowning Pikmin and etcetera). They might ideal choices used when using Candypop Buds since they will not leave the cave you find them in. These abilities are superb, but its fighting strength isn't very potent. They have only appeared in Pikmin 2.
Other Colors
If the player gathers every ship part in the first Pikmin game, they will see several different colors of onions. These include silver, orange, black, pink, green, and light blue. It is unknown whether or not these colors will appear in future games.