Christophe Courteau / African elephants (Loxodonta africana) walking in the dry Hoanib River, Damaraland, Namibia.

Christophe Courteau / African elephant (Loxodonta africana) dust bathing in the dry Hoanib River, Damaraland, Namibia.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Hugh Pearson / Aerial view of Hoanib River, Namibia, September 2011.

Christophe Courteau / Desert dwelling African elephants (Loxodonta africana) matriarch leading her family in the Hoanib River bed, Damaraland. Namibia.

Christophe Courteau / Desert dwelling African elephant (Loxodonta fricana) bull standing up to browse high branches in the dry river bed of the Hoanib River, Damaraland, Namibia.

Christophe Courteau / Desert dwelling African elephant (Loxodonta fricana) bull standing up to browse high branches in the dry river bed of the Hoanib River, Damaraland, Namibia.

Chris & Monique Fallows / African elephant (Loxodonta africana), bull trying to attract female, Hoanib River, Namibia, November.

Chris & Monique Fallows / African elephant (Loxodonta africana) Hoanib River, Namibia, November.

Chris & Monique Fallows / African elephant (Loxodonta africana), Desert dwelling elephant, Hoanib River, Namibia, November 2014

Christophe Courteau / Reticulated giraffe (Giraffa camelopardalis) desert dwelling giraffe in Damaraland, Namibia

Christophe Courteau / Reticulated giraffes (Giraffa camelopardalis) desert dwelling giraffes in Damaraland, Namibia

Theo Allofs / African Elephant (Loxodonta africana) feeding on Acacia (Acacia sp) tree, Hoanib River, Namib Desert, Namibia

Theo Allofs / Angolan Giraffe (Giraffa giraffa angolensis) in desert, Hoanib River, Namib Desert, Namibia

Tom Hugh-Jones / Presenter Steve Leonard and Saba Douglas-Hamilton, on location for BBC Extreme Animals series, in vehicle with African elephant mock charging, Hoanib river, Namibia, 2001

Patrick Morris / African elephant {Loxidonta africana} bull feeding on dune parsley, Hoanib flood plain, Skeleton Coast NP, Namibia

ANDREW MURRAY / African elephant family {Loxodonta africana} migrate across dry Hoanib river, Namibia, Southern Africa

Doug Allan / Ephemeral 'sand river' bed in dry season, Hoanib, Namibia

ANDREW MURRAY / African desert elephants (Loxodonta africana) in dry riverbed of Hoanib River, Namibia

Sharon Heald / African desert elephant drinking at manmade waterhole {Loxodonta africana} Kaokoland, Namibia , Hoanib river

Doug Allan / Ephemeral sand river-bed, Hoanib, Namibia

ANDREW MURRAY / African desert elephants walking along dry Hoanib River bed, Namibia

ANDREW MURRAY / African desert elephants walking in dry Hoanib River bed, Namibia

Tony Heald / African desert elephant with calf {Loxodonta africana} Hoanib river, Kaokoland, Namibia

Theo Allofs / African Elephant (Loxodonta africana) bulls walking behind each other, Hoanib River, Namib Desert, Namibia

Theo Allofs / African Elephant (Loxodonta africana) bull grazing, Hoanib River, Namib Desert, Namibia

Tom Hugh-Jones / Steve Leonard and Saba Douglas-Hamilton on location in Hoanib river Namibia Africa. 2001

Tom Hugh-Jones / Steve Leonard and Saba Douglas-Hamilton with elephants Hoanib river Namibia Africa

Eric Baccega / African desert elephant (Loxodonta africana) juveniles play fighting, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) herd walking in line, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) portrait, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) walking in dry Hoanib Riverbed, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) herd walking on the dry Hoanib Riverbed, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) eating vegetation on the dry Hoanib Riverbed, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana), walking and eating vegetation on the dry Hoanib Riverbed, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana), bull walking on the dry Hoanib Riverbed, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) herd with calf walking, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) pair walking, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana), drinking from waterhole, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) family group resting in the shade and playing, Hoanib River, Damaraland, Namibia.

Eric Baccega / African desert elephant (Loxodonta africana) family group resting in the shade and playing, Hoanib River, Damaraland, Namibia.

Eric Baccega / Gemsbok (Oryx gazella) standing in grass, Hoanib river, Damaraland, Namibia.

Theo Allofs / African Elephant (Loxodonta africana) bull in dry river bed, Hoanib River, Namibia

Theo Allofs / African Elephant (Loxodonta africana) mother and calf, Hoanib River, Namibia

Theo Allofs / African Elephant (Loxodonta africana) group in desert, Hoanib River, Namibia

Theo Allofs / African Elephant (Loxodonta africana) herd, Hoanib River, Namibia

Theo Allofs / African Elephant (Loxodonta africana) mother and calf, Hoanib River, Namibia

Theo Allofs / African Elephant (Loxodonta africana) breeding herd, Hoanib River, Namibia

Christophe Courteau / Hoanib River mouth, Skeleton Coast National Park, Namibia