Eric Medard / Kestrel (Falco tunninculus) female about to defecate off branch, France, May

Eric Medard / Kestrel (Falco tunninculus) female about to defecate off branch, France, May

Eric Medard / Kestrel (Falco tunninculus) female about to defecate off branch, France, May

Carol Walker / Cowboy's horse tethered to small wooden hut, Wyoming, USA, February 2012

Merryn Thomas / Heads aboard Bristol Pilot Cutter "Morwenna", Bristol Floating Harbour, UK. April 2009.

Merryn Thomas / Heads aboard Bristol Pilot Cutter "Morwenna", Bristol Floating Harbour, UK. April 2009.

Onne van der Wal / Toilet bucket on the trampoline of 30ft Tiki catamaran "Abaco". Exumas, Bahamas, Caribbean. June 2009, property released.

Petra Wegner / Sacred Cat of Birma / Birman lilac-tabby-point, in litter tray.

Petra Wegner / Sacred Cat of Birma / Birman, lilac-tabby-point, in litter tray.

Petra Wegner / Sacred Cat of Birma / Birman, seal-point, in litter tray.

Petra Wegner / Sacred Cat of Birma / Birman, seal-point, in litter tray.

Petra Wegner / Sacred Cat of Birma / Birman, seal-point, in litter tray.

Petra Wegner / Sacred Cat of Birma / Birman, lilac-tabby-point, in litter tray.

Bryan and Cherry Alexander / Woman using the field toilet at Mount Vinson Base Camp. Vinson Massif, Antarctica, January 2006.

Bryan and Cherry Alexander / Woman using the field toilet at Mount Vinson Base Camp. Vinson Massif, Antarctica, January 2006.

Bryan and Cherry Alexander / Woman visiting the field toilet at Mount Vinson Base Camp. Vinson Massif, Antarctica, January 2006.

Matthew Maran / A toilet cubicle in a wooden shelter. The West Coast Trail, Pacific Rim National Park, Vancouver Island, Canada, September 2010.

Bryan and Cherry Alexander / Nenets woman scraping log for shavings used for toilet paper and nappies / diapers. Yamal, Siberia, Russia, 1993.

Bryan and Cherry Alexander / Siamese cat urinating into a toilet. Yamal, Siberia, Russia, 2003.

Bryan and Cherry Alexander / Remains of outside toilet at old polar station at Tichaya Bay. Hooker Island, Franz Josef Land, Russia, 2004.

Bryan and Cherry Alexander / Woman using an outdoor toilet screened from the wind by a wall of snowblocks. Nunavut, Canada, 1999.

David Woodfall / Rust mark on toilet showing level of flooding in monsoon, Bangladesh, November 2008

David Woodfall / Building an outside toilet in industrial slum, Bhopal, Madhya Pradesh, India, November 2008

Oriol Alamany / Green Tree Frog (Litoria caerulea) in toilet bowl at campsite, Townsville, Queensland, Australia, December

Jerry Monkman / Door of outhouse toilet, Kennicott, Wrangell - St Elias NP, Alaska, USA

Robert Valentic / Outback 'dunny' (toilet) with bullet holes, Bourke, New South Wales, Australia

Jane Burton / Jack Russell Terrier-cross, 14-week puppy urinating

Jane Burton / Jack Russell Terrier-cross, 8-week puppy peeing

Jane Burton / Rear-view of pomeranian bitch, 10-week puppy urinating

Petra Wegner / Domestic dog, Small Dutch Waterfowl Dog / Kooiker Hound / Kooikerhondje puppy, 3 months, wrapped with toilet paper

Petra Wegner / Domestic dog, Small Dutch Waterfowl Dog / Kooiker Hound / Kooikerhondje puppy, 3 months, wrapped with toilet paper

Petra Wegner / Persian Cat kitten, using litter tray

Petra Wegner / Persian Cat kitten, using litter tray

Petra Wegner / Persian Cat kitten, using litter tray

Petra Wegner / Persian Cat kitten, stepping into litter tray

Petra Wegner / Cavalier King Charles Spaniel (tricolour) wrapped in toilet paper

Petra Wegner / Domestic dog, Small Dutch Waterfowl Dog / Kooiker Hound / Kooikerhondje puppy, 3 months, playing with roll of toilet paper

Petra Wegner / Persian Cat, kitten, using litter tray

Tony Heald / Lions {Panthera leo} resting in shade of toilet building at picnic site, Kalahari Gemsbok NP, South Africa