In addition to the tusks of the African and Indian elephant, the teeth of hippopotamus, sperm whale, Narwhal, walrus and wild boar have been used for carving artifacts. Animal bone, often used in imitation of ivory, is lighter, thinner and has a spongy interior due to the Haversian canals which once contained blood vessels. Methods of treatment for ivory and bone objects are essentially the same, but vary according to their age and condition, archaeological items recovered from the earth requiring special care. All ivories, however, react to changes in temperature and humidity and should be stored with a constant 65-70 F temperature and a 45-60% R.H. And displayed with protection from strong light. Materials for cleaning and repairing ivories are described.