Cloth Scavenging

Cloth Scavenging is a passive trait exclusive to tailors. It gives the tailor a chance to find additional cloth on humanoids, including those from other players (after they have looted the corpse).

As this was added in Wrath of the Lich King, the tooltip originally specifically mentioned mobs in Northrend, but the effect itself has been continually applied to mobs at higher levels, such as those in Cataclysm and Mists of Pandaria.