To completely drain the average human of blood July 30, 2014 in Body Facts, Strange Facts It would take 1,200,000 mosquitoes, each sucking once, to completely drain the average human of blood. It would take 1,200,000 mosquitoes, each sucking once, to completely drain the average human of blood. Review OverviewUser Rating: Be the first one ! 0 facts Strange 2014-07-30 Admin Share ! tweet