Neil Aldridge / Portrait of an African wild dog (Lycaon pictus) wearing a radio collar in dense mopane bushveld, Venetia Limpopo Nature Reserve, Limpopo Province, South Africa, February 2010.

Petra Wegner / Cavalier King Charles Spaniel, puppy, black-and-tan, 6 weeks, sitting on grass, wearing collar.

Mark Raycroft / Border Collie (Canis familiaris) adult with three tennis balls in its mouth, waiting to play fetch

Mark Raycroft / Weimaraner (Canis familiaris) looking out from barn

TJ Rich / Golden cocker spaniel puppy aged 12 weeks, with collar and name tag, sitting in armchair, portrait. Wirral, England, UK.

TJ Rich / Golden cocker spaniel puppy aged 12 weeks, with collar and name tag, sitting in armchair, portrait. Wirral, England, UK.

Nick Upton / Spanish mastiff guard dog (Canis domesticus) wearing a metal spiked carlanca collar to protect it from wolves, protecting a herd of sheep on pastureland above the Lakes of Covadonga, Asturias, Spain,...

TJ Rich / Black cockpoo sitting. Wiltshire, UK

TJ Rich / Jack Russell Terrier sitting, rescue dog, Wiltshire, UK

TJ Rich / Jack Russell Terrier, Wiltshire, UK

TJ Rich / Jack Russell Terrier listening to owner, rescue dog, Wiltshire, UK

TJ Rich / Black cockpoo sitting at cottage door. Wiltshire, UK