Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) group wallowing in mud at night, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) group wallowing in mud at night, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) group wallowing in seasonal pond, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) group wallowing in seasonal pond, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) group wallowing in seasonal pond, Alcedo Volcano, Isabela Island, Galapagos Islands, Ecuador

Andy Rouse / African Elephant (Loxodonta africana) mother and calf in rain, wallowing in mud. Maasai Mara, Kenya, Africa. September.

Anup Shah / African elephants (Loxodonta africana) wallowing at a waterhole, wide angle view. Maasai Mara National Reserve, Kenya.

Ammonite / Baird's tapir (Tapirus bairdii) entering a pool of water and wallowing, footage taken at night using thermal camera technology, Santa Rosa National Park, Costa Rica.

Anup Shah / African elephants (Loxodonta africana) wallowing in a waterhole. Masai Mara National Reserve, Kenya. Taken with remote wide angle camera.

Denis-Huot,Denis-Huot / Hippopotamus (Hippopotamus amphibius) males in a muddy pond, aerial view, Rwindi national park, Democratic Republic of Congo. Vulnerable species.

Anup Shah / African Forest elephant (Loxodonta africana cyclotis) herd drinking and wallowing in a river, Bai Hokou, Dzanga Sangha Special Dense Forest Reserve, Central African Republic. December 2011.

Tui De Roy / Volcan Alcedo giant tortoises (Chelonoidis nigra vandenburghi) wallowing in rain pools on caldera floor, possibly for thermoregulation or detering parasites, with sulphur fumaroles in background, Alce...