Desert elephant

They tend to migrate from one waterhole to another following traditional routes which depend on the seasonal availability of food and water.

The Kunene Region in the northwest of Namibia is an area of mostly sandy desert, rocky mountains and stony plains; it covers about 115,154 square kilometres (44,461 sq mi).

At certain times during the year they move inland along narrow traditional paths to mountain areas in search of myrrh bushes (Commiphora spp.)

Nowadays they are restricted to the Gourma area, a remote region in Mali south of a loop made by the River Niger near Timbuktu.

These elephants are remaining members of a number of groups which used to inhabit large areas of the Sahel as recently as 1970, before they were eliminated - mostly by poachers.

The elephants follow an anticlockwise route that takes them past temporary and permanent water holes.

They are elusive and tend to seclude themselves among Acacia trees during the day, emerging to drink and feed at night.

Some animals were fitted with GPS collars to track their movements and identify corridors through which they need to traverse to complete their journey, so that their routes could be avoided when new human settlements were established.

In the wet season they prefer buds and fresh green leaves, but in the dry season they survive on drought-tolerant plants such as the camelthorn (Acacia erioloba), myrrh bushes, the mopane or turpentine tree (Colophospermum mopane) and the leaves and seedpods of the ana tree (Faidherbia albida).