Blindsense (Universal Monster Rule)

Using nonvisual senses, such as acute smell or hearing, a creature with blindsense notices things it cannot see. The creature usually does not need to make Perception checks to notice and locate creatures within range of its blindsense ability, provided that it has line of effect to that creature. Any opponent the creature cannot see still has total concealment against the creature with blindsense, and the creature still has the normal miss chance when attacking foes that have concealment. Blindsense does not allow a creature to see anything within range that it could not otherwise see; it just notices that something is there.