>>51383857I always assumed most active Volcanos had a Heatran around, somewhere. If we can assume that's correct, a quick search showed me there are currently 1350ish active volcanos in the world.
If we assumed there were that many Heatrans, it would still be extremely rare, and also serve a basis for a breeding population given their male and female genders. Even if we said one in a hundred volcanos had a Heatran, that's still 35 Heatrans.