Loic Poidevin / Sheep (Ovis aries) flock herded together with ear tags and paint markings. Ossoue valley, French Pyrenees, September.

LYNN M. STONE / Shorthorn cow, head portrait in lush pasture; South Randolph, Vermont, USA

Peter Cairns / naturepl.com / Red deer (Cervus elaphus) hind on deer farm with ear-tag, Strathfarrar, Scotland, UK, June

Peter Cairns / naturepl.com / Red deer (Cervus elaphus) hind on deer farm with ear-tag, Strathfarrar, Scotland.

Peter Cairns / naturepl.com / Upland water vole (Arvicola terrestris) is fitted with ear tag as part of conservation project, Cairngorms, Scotland, UK, July 2008

Donald M. Jones / American Elk (Cervus elaphus nelsoni) cow with radio-collar and ear tag, western Alberta, Canada

Rob Cousins / Devon "Ruby" Red cattle (Bos taurus) feeding on hay, UK

Michael Hutchinson / Jersey cow (Bos taurus) close up, Cornwall, UK

Michael Hutchinson / Jersey cow (Bos taurus) close up portrait, Cornwall, UK

LYNN M. STONE / Domestic cattle, Piedmontese cow with ear tag, Wisconsin, USA

Suzi Eszterhas / Polar Bear {Ursus maritimus} anaesthetised 3/4-months cub with new ear tag, Wapusk NP, Manitoba, Canada

Eric Baccega / Rangers fit an ear tag on a female Black bear Parc National de la Mauricie Canada.

Richard Du Toit / Impala with radio tracking collar and ear tag {Aepyceros melampus} Chobe NP Botswana

Michael Durham / Bighorn ram {Ovis canadensis canadensis} with identification ear tag and collar, Wallowa Mountains, Oregon, USA

Michael Durham / Bighorn ram {Ovis canadensis canadensis} marked with an ear tag and radio collar. Wallowa Mountains, Oregon, USA

Suzi Eszterhas / Polar Bear (Ursus maritimus) three to four month old cubs waking up from anesthesia after receiving lip tattoo and ear tags, vulnerable, Wapusk National Park, Manitoba, Canada

Suzi Eszterhas / Polar Bear (Ursus maritimus) ear identification tag of adult female, vulnerable, Wapusk National Park, Manitoba, Canada