Subterranean termites live in underground colonies or in moist secluded areas aboveground. Their colonies can contain more than a million members. They build characteristic "mud tubes" from mud, saliva and fecal matter. These tubes act as entry points for subterranean termites to gain access to above-ground food sources and to protect themselves from open air. Subterranean termites are most commonly located near the foundation of an infested home.