In Calgary, the most commonly seen arachnids are cellar spiders, fishing spiders, house spiders, wolf spiders and occasionally black widow spiders. Some are web builders and others actively hunt their prey. The majority are not a threat to humans. Additionally, they commonly eat a number of pesky insects. Despite the possible benefits the creep factor associated with spiders generally makes the arachnid an unwelcome guest in homes. Outside of the oddly brave spider that appears on a floor, wall or ceiling, most prefer dark, secluded places. Telltale signs commonly include webs and egg sacs. Effectively eradicating spider populations often involves multiple treatments performed by pest control professionals in order to get the arachnids during all phases of a life cycle.