Kilimanjaro is what is known as a strato-volcano. This basically means it is one very big ash pile built up over the course of many eruptions. Fortunately it is now dormant. The last major eruption was about 360,000 years ago. Kilimanjaro has 2.2 square kilometres (0.85 sq mi) of glacial ice but is losing it quickly. The glaciers have shrunk 82% since 1912 and declined 33% since 1989. It might be ice free within 20 years.
As you climb Kilimanjaro you pass through 5 distinct climate and vegetation zones. On the Lower Slopes between 2,600 feet and 5,900 feet, the climate is tropical. The Rain Forest zone between 5,900 and 9,200 feet receives the highest amount of rainfall, up to 78 inches per year. The moisture results in a belt of dense tropical rain forest. The moorland zone is between 9,200 feet and 13,100 feet. This is covered with heather and bright flowers. Between 13,100 and 16,400 feet there is a semi-desert region that receives less than 10 inches of rain annually. Only plants such as moss or lichens can survive here. The summit zone above 16,400 feet is an icy wasteland, baked by fierce sunshine during the day and frozen at night. The thin air here contains half as much oxygen as at sea level.
In spite of the tough climate there are over 140 species of mammals living on Kilimanjaro. At least seven larger mammal species have been recorded above the tree line including tree hyrax, grey duiker, red duiker, eland, bushbuck, buffalo and elephants. Three primate species also live in the montane forests: blue monkeys, black and white colombus monkeys and bushbabies.