For many Big Issue vendors, having a canine companion or a feline friend can offer some much-needed company while selling the magazine.
But pets can also be a barrier to securing accommodation, with many homeless shelters, hostels or private rental properties operating a strict no animal policy.
This was also a problem in the Brazilian city of São Paulo where, despite the number of homeless people swelling to 20,000, shelters were being left deserted after people opted to stay on the streets rather than abandon their pets.
Officials tackled the problem by building temporary accommodation that also featured spots for pets in kennels.
But how could they get the message out to the homeless people of the city, many of whom are without access to the internet, social media and other forms of communication?
The answer lay in graffiti. Officials enlisted the help of Nova/sb, a São Paulo-based advertising agency, to mobilise five street artists – Galo, Randal, Pixote, Thassio and René Muniz – to spray the way to the centres.