EDIT: The Legendary Beasts are thought to be based on mythological creatures:
Raikou is a raiju (a.k.a. a tiger).
Suicune is a kirin (a.k.a. a wolf).
Entei is a shishi (a.k.a. a lion-dog fusion).
Please check the related links below to see an image explaining in more detail this theory, along some photos.
Raikou looks like it should be a member of the big cat family so personally I would place Raikou as a tiger cross with a lion and a lot of media magic.
Raikou is only found in firered and leafgreen if you chose squirtle as your starter Pokemon. Or you can get the purified raikou from Pokemon colosseum.
Raikou isn't on Pokemon Pearl, if you want it you must transfer it from another game
electric
If you chose Bulbasaur or Charmander as your starter pokemon, then Raikou can't be found in the wild. If you chose Squirtle, however, Raikou can randomly be found in the wild (excluding Sevii Islands.)
Raikou doesn't have a nest, it runs randomly around Johto.
Raikou is a tiger.
The legendary pokemon Raikou is based off of a tiger :D I effin love pokemon
raikou cannot be caught on Pokemon ruby
to catch Pokemon you have to obtain raikou palls
Raikou is only found in firered and leafgreen if you chose squirtle as your starter Pokemon. Or you can get the purified raikou from Pokemon colosseum.
You cant get raikou in Pokemon diamond or Pokemon pearl.But you can get him in a gba Pokemon game and transfer him to your Pokemon pearl or diamond!
You can't find raikou in ruby.
Raikou isn't on Pokemon Pearl, if you want it you must transfer it from another game
you can't. raikou is a generation 2 Pokemon. Pokemon blue is a generation 1 game. so it is impossible!
You cannot catch Raikou in Pokemon Diamond and Pearl. To get Raikou in Pokemon Diamond and Pearl, you must trade for one from Pokemon HeartGold and SoulSilver where it can be caught or transferring from Pokemon FireRed and LeafGreen.
raikou is better
You go to a mountain and catch raikou