in the days and weeks that follow, few dinosaurs remain. in mongolia, the starving "charonosaurus" stays close to the cave that has saved it twice in the past. suddenly, it collapses, but not from starvation. bubbling to the surface from hot springs is one of nature's most toxic gases; hydrogen sulfide. the "troodon" runs up to the dead "charonosaurus". then it too dies from inhaling the poisonous gas.