Relatives of the common mud dauber wasp, cliff hornets were social insects who built their nest in cracks, crevices, and fissures in the sides of cliffs. Although they would not build nests deep underground, their homes could sometimes be found as much as several hundred feet from a cave entrance if a good nesting site could be found there. These insects were not normally dangerous unless one was an intruder who had blundered into the midst of a nest. Then the outraged hornets would attack en masse with their sharp, barbless stingers, injecting the victim with a venom that would, at minimum, cause pain and swelling. In addition, many people were allergic to cliff hornet venom and might die from its effects.