Pikachu (ピカチュウ, Pikachū?) are one of the 493 fictional species of Pokémon creatures from the multi-billion-dollar Pokémon media franchise—a collection of video games, anime, manga, books, trading cards, and other media created by Satoshi Tajiri. As do all Pokémon, Pikachu fight other Pokémon in battles central to the anime, manga, and games of the series. Pikachu is among the most recognizable of Pokémon, due to the fact that a Pikachu is a central character in the Pokémon anime series.
The name Pikachu is a portmanteau of the Japanese words pikapika, an onomatopoeia for electric sparkling, and chū, which is the Japanese onomatopoeia for a mouse's squeak. It may also be based on the pika. The name Pikachu refers to both the overall species, and to individual Pikachu within the games, anime, and manga series. Pikachu is also the name of an individual character that belongs to this species and is the Pokémon companion of the anime's main protagonist, Ash Ketchum.
In the Pokémon franchise, Pikachu are often found in forests, plains, and occasionally near mountains, islands and electrical sources (such as power plants), on most continents throughout the world. Pikachu often travel in packs, and are rarely territorial; however, when threatened, a group can generate an intense electrical offensive, and the electro-magnetic forces exerted by the resulting field can even produce a short-lived, localized thunderstorm.
Pikachu are short, stocky mouse Pokémon that possess short, yellow fur with brown markings covering their backs and parts of their tails. They have black-tipped pointy ears and light red circles on their cheeks, which contain electrical sacs. Their tails are shaped in the form of a lightning bolt. In Pokémon Diamond and Pearl, gender differences were introduced for some Pokémon. For Pikachu, the females now have a "dent" at the end of their tails given it a heart shaped appearance.
Pikachu often forage for berries. In lieu of climbing trees they use small electrical bolts to release the berries from the tree, roasting them at the same time. For fallen berries, they use their electricity to roast the berries with electricity, tenderizing them. They store electricity in their cheeks, and by simply squeezing them they can discharge them in sparks, bolts or other forms of electricity. An inability to discharge electricity in this last way, as in the presence of strong magnetic field, causes an illness with flu-like symptoms. Pikachu gather in areas with high amounts of thunderstorm activity such as power stations.
Pikachu evolve into Raichu via use of a Thunder Stone. However, it is somewhat common for Trainers to choose not to evolve their Pikachu into Raichu. For example, in Pokémon Yellow, Pikachu refuses to evolve as attempting to use a Thunderstone on it makes it cry and refuse. It is numbered as #25 in the National Pokédex. Also, from the second generation of the Pokémon games onward, Pikachu has an evolutionary predecessor, Pichu, which is the pre-evolution of Pikachu and evolves into Pikachu after establishing a friendship with its trainer. Wikipedia
_-_Pikachu.jpg "Pokemon (Pocket Monsters) - Pikachu")