This is a single tooth of the African Elephant, Loxodonta africana. An Elephant tooth has a series of enamel ridges or lamellae that are an effective adaptation for grinding the coarse grases and bark that make up their dies. The upper and lower teeth move forward and backwards as the animal chews.
An elephant has a series of 6 molars throughout its lifetime that erupt sequentially and move forward in the mouth as the next one begins to erupt, chipping away and falling out at the front. Usually only two of these teeth are in wear at any one time. Once the sixth and final molar is in wear and eventually is worn down then the animal reaches the end of its life.