As the reasoning and critical thinking portions of a ghoul's brain deteriorate, the ghoul subject becomes increasingly hostile, giving in to a carnal need to feed. It is known that normal ghouls can turn feral when exposed to excessive levels of radiation. As with normal ghouls, ferals are not only extremely resistant to radiation, they are actually healed by it, as can be seen when a glowing one uses its radiation blast nearby other ghouls. M.A.R.Go.T. also states that feral ghouls have no internal body heat.