No no no no no, how stupid can you get?
First of all, I know it's just a dumb little theory, don't throw stones at the mexican xO
So you take a Cubone sprite and mutilate it a little, and claim that malnutrition can cause mutation??? He said the baby Kangashkan was "seperated" from its mother, well if that's so then how did he get the skull? The mother had to have died, the baby stick around until the skull is completely cleaned out by predators, and later lesser organisms. The baby would have probably been eaten by the predators, died of starvation, or been killed by disease from the mothers rotting corpse by then =P. If that were the case, then we'd see a lot less Cubone in the cave next to the burial tower =P
Cubone ALONE doesn't make sense, making a theory of how it exists due to mutation caused by malnutrition is ludicrous.
It's still a cool theory though *o*