Level 42.
Rhyhorn evolves into Ryhdon at level 42. Its the second highest of the original 150Pokemon. The highest being Dragonite at level 55. For anyone else who may want to know, all the evoloution levels are the same for Leaf Green and Fire Red.
Level 42
Rhyhorn evolves at level 42 into Rhydon
He doesn't you need to give them a protector them trade them.
Several other Pokemon evolve this way.
Check out:
http://bulbapedia.bulbagarden.net/wiki/Protector#Protector
There is a list.
Not level, By via trade with another DS in the union room.
He evolves at level 42.
lvl 42
lvl 42
Level 42
level35
level 42 then trade to get ryperior
Crobat doesn't evolve.
Level 32.
Lv20
Wooper will evolve at level 32.
Rhyhorn will evolve at Level 42.At level 42 in Rhydon.Rhyhorn evolves at level 42.
Level 42.
level 42
Rhyhorn evolves into Rhydon at level 42 in Pokemon Emerald Version.
level 42
Level 42
Rhyhorn evolves into Rhydon at level 42.
give a sooth bellto rhyhorn and train to level 42
..........level rhyhorn to 42.....get a rhyhorn from safari and evolve it to rhydon
level it up to level 42.
Rhyhorn is one of the Pokemon that take a while to evolve. You have to level it up to level 42 in order for it to evolve into Rhydon. If you give Rhydon a protector and trade him, then he evolves into Rhyperior.
level 42 or 44