digglet/dugtrio
Yes, Pikachu is able to learn Dig. It can learn Dig through the use of the Dig TM, which you can buy at the Cerulean City Poke Mart.
i don't think that any Pokemon can learn dig by itself but alot of Pokemon can learn it from the TM. if you don't have the TM then you cant teach your Pokemon dig
Trapinch can learn Dig by itself at level 29 in Pokemon X and Y. In Pokemon Omega Ruby and Alpha Sapphire, it can learn Dig at level 19.
Sandshrew learns dig at level 30 in Pokemon Sapphire. The ability to naturally learn dig make Sandshrew a valuable Pokemon. Since he can learn dig itself you don't have to use the TM dig on it.
Linoone can learn Dig by using the TM Dig. It cannot learn Dig by leveling up.
Yes, it can learn Dig by teaching it with the TM Dig. It cannot learn Dig by leveling up.
Camerupt can learn Dig by using the TM Dig. It cannot learn Dig by leveling up.
Yes, Lucario is able to learn Dig. It can learn it through the use of the Dig TM.
Yes, Rhydon can learn Dig by using a TM. It doesn't learn Dig by leveling up.
Yes, Numel can learn Dig, but it can only learn Dig by using the TM and not by leveling up.
Baltoy can only learn Dig by using the TM. It cannot learn Dig by leveling up.
Linoone does not learn Dig by leveling up, instead it needs the TM to learn Dig.