Pet-keeping is a widespread and well-accepted phenomenon in today’s society. As a nation of self-confessed ‘animal lovers’, the British public now share their homes with over 8 million cats and 8 million dogs (Pet Food Manufacturer’s Association, 2011). These companion animals can play an enormous role in their owners’ lives. As well as providing a source of companionship, support and entertainment, there is now substantial evidence to suggest that such animals may be able to promote their owners’ health (for reviews see http://www.pfma.org.uk/pet-population-2011/, http://www.fci.be/stats.aspx, Wells, 2007, Wells, 2009 and Wells, 2011).