Elephant tusks evolved from teeth, giving the species an evolutionary advantage. They serve a variety of purposes: digging, lifting objects, gathering food, stripping bark from trees and defense.

The tusks also protect the trunk, and the dominant tusk is usually more worn as a result of frequent use.

Both male and female African elephants have tusks, while only male Asian elephants have tusks, and then only a certain percentage.

Poachers kill about 20,000 elephants for their tusks every year. The tusks are then illegally traded in the international market and eventually end up as ivory trinkets. Apart from the United States, Asian countries have the highest demand for ivory.

With approximately 293,000 elephants, southern Africa has by far the largest number, accounting for 70 percent of the animals on the continent. It's followed by eastern Africa with an estimated 86,000, and central Africa has 24,000, according to figures released in September. West Africa has the smallest elephant population, about 11,000.

In August, the Great Elephant Census released the results of a two-year project in 18 African countries. Costing $7 million, it was the largest wildlife survey in history, and was designed to provide accurate data about the numbers and distribution of African elephants via standardized aerial surveys of hundreds of thousands of square kilometers.

The census showed a 30 percent decline in the number of African savanna elephants in 15 of the 18 countries surveyed. The reduction occurred between 2007 and 2014, representing a loss of approximately 144,000 elephants - largely as a result of poaching.

The total number of savanna elephants in Africa is 352,271, far lower than previously estimated.

Source: the world wide fund for nature