i dont think you can, you can get the dogs only by action replay
You cannot get the Legendary Dogs (or Beasts such as Raikou, Suicune and Entei) in Ruby without either trading for them or cheating for them because they are not available in the wild in Ruby in any way, shape or form. But you can catch it in Pokemon Ruby Destiny-Reign of Legends. But in the original Ruby or Sapphire you can't get it.
No.
you can catch groudon in ruby in cave of origin then beat the elite four to catch rayquaza on sky pillar
no
no.
Use pokeballs.
In Ruby, Sapphire, or Emerald, the only way to get the legendary dogs is to trade them from a previous game. In Fire Red, and Leaf Green, you can only obtain one dog. The other two you have to trade over. Which ever dog you can get depends on your starter. If you started with Bulbasaur you can catch Entei. If you started with Charmander you can catch Suicune. If you started with Squirtle you can catch Raikou. The dog is roaming around Kanto.
None of the legendary dogs are available in Emerald you must obtain them from Firered, Leafgreen, or Pokemon Colosseum.
By the way, they are the legendary cats, not dogs. The Pokemon Company revealed that Raikou is a tiger, Entei is a lion, and Suicune is a cheetah.
You battle it and you choose whether to catch it or not.
You can get the three legendary birds, Zapdos, Multrace, and Articuno. After you give the Ruby and sapphire to celio (on 1 island) you can go to the cerculean cave and catch Mew two. Now you can get one of the legendary dogs. If you start with Bulbasaur= Entei squirtle=Raikou charmander=sweecone. ( Sorry about spelling!!)
Ho-oh lugia celebi(with a gameshark)