They were collected from an apartment building in the Vancouver area, where apparently a great number of apartments (hundreds) have been hosting them. Despite their minute size (total length barely 2 mm), they can either weakly sting or bite (technically the 'sting' is non-functional). That they can do one of these I can personally attest too as the mattress I was sleeping on in Borneo was infested with the little darlings. They were just big enough that you could feel them walking over you at night (many of them), and when you rolled over on them, they let you know they found that disagreeable.
Despite the fact that this species is tropical to sub-tropical, it has spread to higher latitudes, living in buildings with central heat. This species has colonies with multiple queens (something we myrmecologists call polygynous) and if the colony is stressed (e.g., someone tries to poison or otherwise harass and attempt to remove them), the colony fragments into many smaller colonies, each with one or more queens. Thus, if just one apartment tenant tries to deal with them, they quickly fragment and spread throughout the building. Having said that, they are likely to do that anyway.
Pharaoh's ant is now found throughout the world. When I checked on "The Authority," that is, the person who first described them, I found it was Linnaeus (a Swede) in 1758. They have been travelling for quite awhile.
Photo Credits: Me