Tui De Roy / Black rhino (Diceros bicornis) with very long horn, Lewa Wildlife Conservancy, Laikipia, Kenya. October.

Tui De Roy / Black rhino (Diceros bicornis) and White rhino (Ceratotherium simum), being harrassed by playfighting White rhino bull, Solio Game Reserve, Laikipia, Kenya. September.

Tui De Roy / Black rhino (Diceros bicornis) and White Rhino (Ceratotherium simum) bulls facing off. Solio Game Reserve, Laikipia, Kenya. September.

Tui De Roy / Three White rhinoceroses (Ceratotherium simum) walking together, Solio Game Reserve, Laikipia, Kenya. September.

Tui De Roy / Three White rhinoceroses (Ceratotherium simum), Solio Game Reserve, Laikipia, Kenya. September.

Nick Hawkins / Baird's tapir (Tapirus bairdii) browsing on leaves, rainforest, Corcovado National Park, Costa Rica. Endangered.

Nick Hawkins / Baird's tapir (Tapirus bairdii) walking along a beach in Corcovado National Park, Costa Rica. Endangered.

Nick Hawkins / Baird's tapir female (Tapirus bairdii) with calf, rainforest, Corcovado National Park, Costa Rica. Endangered.

Nick Hawkins / Baird's tapir female (Tapirus bairdii) with calf, rainforest, Corcovado National Park, Costa Rica. Endangered.

Sylvain Cordier / Indian wild ass (Equus hemionus khur) running, Wild Ass Sanctuary, Little Rann of Kutch, Gujarat, India

Will Burrard-Lucas / Black rhinoceros (Diceros bicornis) mother and calf, Lewa & Borana Conservancy, Kenya.

Will Burrard-Lucas / White rhino (Ceratotherium simum) female and juvenile, Solio Game Reserve, Solio Ranch, Kenya. Taken with remote camera buggy / BeetleCam. EDITORIAL USE ONLY. All other uses require clearance

Will Burrard-Lucas / White rhinoceroses (Ceratotherium simum) with calf playing with adult, Solio Game Reserve, Solio Ranch, Kenya. Taken with remote camera buggy / BeetleCam. EDITORIAL USE ONLY. All other uses require cl...

Will Burrard-Lucas / White rhino (Ceratotherium simum), portrait. Solio Game Reserve, Solio Ranch, Kenya. Taken with remote camera buggy / BeetleCam. EDITORIAL USE ONLY. All other uses require clearance

Will Burrard-Lucas / White rhino (Ceratotherium simum), portrait. Solio Game Reserve, Solio Ranch, Kenya. Taken with remote camera buggy / BeetleCam. EDITORIAL USE ONLY. All other uses require clearance

Dong Lei / Kiang (Equus kiang) near Mount Shishapangma, Mt Qomolangma National Park, Qinghai Tibet Plateau, China.

Fabio Pupin / Onager (Equus hemionus), Negev desert, Israel, April.

Neil Aldridge / A young White rhinoceros (Ceratotherium simum) leaves a secure enclosure known as a boma in the Okavango Delta, northern Botswana, after being translocated from South Africa as part of efforts to rebu...

Neil Aldridge / White rhinoceros (Ceratotherium simum) male and female, face to face, Mosi Oa Tunya National Park, Zambia.

Neil Aldridge / Black rhinoceros (Diceros bicornis) stands in evening light on Chief's Island in Okavango Delta, Botswana,. This rhino was released in the Okavango Delta as part of efforts to rebuild the rhino popula...

Neil Aldridge / White rhinoceros (Ceratotherium simum) mother and calf, prepare to leave a boma - a secure enclosure - in the Okavango Delta in northern Botswana after being translocated from South Africa as part of...

Neil Aldridge / Blindfolded and tranquilised adult White rhinoceros (Ceratotherium simum) with a tracking tag lies and recovers in the Okavango Delta, northern Botswana, following a translocation operation that invol...

Neil Aldridge / Five orphaned White rhinoceros (Ceratotherium simum) calves feed from a trough at dusk at the Rhino Revolution orphanage near Hoedspruit, South Africa. The mothers of these rhinos were killed by poach...

Neil Aldridge / White rhinoceros (Ceratotherium simum) with a long horn, Marakele National Park, South Africa.

Neil Aldridge / Team of vets and conservation staff move a sedated White rhinoceros (Ceratotherium simum) into a comfortable resting position in a secure enclosure known as a boma during a translocation operation to...

Anup Shah / Mixed herd of Common or Plains zebra (Equus quagga burchellii) and Eastern white-bearded wildebeest (Connochaetes taurinus) - remote camera. Masai Mara National Reserve, Kenya.

Enrique Lopez-Tapia / Kiangs (Equus kiang) on grassland near Tso Kar Lake, Chantang Wildlife Sanctuary. Ladakh, India, September 2018.

Bence Mate / Zebra at waterhole at night, Mkuze, South Africa Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Bence Mate / African elephant (Loxodonta africana) and Zebra (Equus quagga) at waterhole at night, Mkuze, South Africa Third place in the Nature Portfolio category of the World Press Photo Awards 2017.

Ann & Steve Toon / White rhino (Ceratotherium simum) at waterhole at night, Zimanga Private Game Reserve, KwaZulu-Natal, South Africa.

Ann & Steve Toon / White rhino (Ceratotherium simum) at waterhole drinking at night, Zimanga Private Game Reserve, KwaZulu-Natal, South Africa.

Ann & Steve Toon / Cape buffalo (Syncerus caffer) at waterhole at night with plains zebra (Equus quagga), Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Ann & Steve Toon / Plains zebra (Equus quagga) drinking at waterhole at night, Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Ann & Steve Toon / RF - Warthog male (Phacochoerus africanus) drinking, Zimanga game reserve, KwaZulu-Natal, South Africa, June. (This image may be licensed either as rights managed or royalty free.)

Neil Aldridge / White rhinoceros (Ceratotherium simum) calf keeping close to its mother on Kariega Game Reserve, South Africa.

Neil Aldridge / White rhinoceros (Ceratotherium simum) female 'Thandi' silhouetted against the sunset, Kariega Game Reserve. South Africa. Thandi's horns were taken in a brutal attack by poachers.

Neil Aldridge / Plain's zebra (Equus quagga) biting the neck of a rival during a fight Hluhluwe imfolozi Park. South Africa.

Neil Aldridge / Plain's zebra (Equus quagga) close up of face, Kariega Game Reserve. South Africa.

Neil Aldridge / Black rhinoceros (Diceros bicornis) feeding in early morning light, Kariega Game Reserve. South Africa.

Carol Walker / Two wild pinto Mustang stallions battle for dominance in Sand Wash Basin, Colorado, USA.

Carol Walker / Wild pinto Mustang mare and foal running in Sand Wash Basin, Colorado, USA.

Carol Walker / Head portrait of grey Arabian stallion running in desert dunes near Dubai, United Arab Emirates.

Carol Walker / Two wild Mustang stallions fighting in the White Mountain Herd Area, Wyoming, USA. August.

Carol Walker / Two white Camargue horses in ocean of Camargue, France, Europe. May.

Carol Walker / Wild Mustang horse rearing, Pryor mountains, Montana, USA. June.

Ingo Arndt / Masai giraffe (Giraffa camelopardalis tippelskirchi) males fighting, Masai Mara National Reserve, Kenya. Sequence 3 of 3

Floris van Breugel / Wild horse / mustang in open landscape, White Mountains, California, USA, July