The creature is able to detect all life forms within a given radius, based upon its level. No skill check of any sort is required for this. This ability works through all forms of cover and concealment. A creature that is seen via Life Sense never gains any benefit from Concealment.

This ability has a number of minor limitations. First, it can only detect living beings. It cannot locate any sort of undead, construct or any other non-living being. Second, it does not allow the creature to actually view any details about the life form it detects. All that can be seen is its location and a rough guess as to its size.