Large herbivores such as elephants often seek out natural mineral deposits such as rocks and soil to supplement their dietary intake of sodium whenever the mineral is not obtained in adequate quantities from woody plants and natural water which elephants consume. So it is not uncommon to find elephants devouring soil and licking rocks high in sodium content. In Mount Elgon National Park on the Kenya-Uganda border, elephants have taken this activity a step further—they have learned to quarry sodium-rich rocks on the base of a 24-million-years-old extinct volcano called Mount Elgon.