Flea circus. Children watching a performance of the Hans Mathes Flea Circus. This circus features trained human fleas (Pulex irritans) performing a range of tricks and stunts. These include kicking balls, pulling miniature carriages and dancing in tiny costumes. The tricks rely on the natural movements of the fleas and on their strength; they can carry objects of 20,000 times their own body weight. The circus performs to audiences of up to 20 people, children taking the front seats. The fleas are viewed through a magnifying glass held by an assistant, as seen here. The circus performs for 2 weeks a year at the Munich Oktoberfest in Germany.