A flea circus refers to a circus sideshow attraction in which fleas are attached (or appear to be attached) to miniature carts and other items, and encouraged to perform circus acts within a small housing.
The first records of flea performances were from watchmakers who were demonstrating their metalworking skills. Mark Scaliot in 1578 produced a lock and chain which were attached to a flea. Flea performances were first advertised as early as 1833 in England, and were a major carnival attraction until 1930. Some flea circuses persisted in very small venues in the United States as late as the 1960s. The flea circus at Belle Vue Zoological Gardens, Manchester, England, was still operating in 1970. At least one genuine flea circus still performs (at the annual Oktoberfest in Munich, Germany) but most flea circuses are a sideline of magicians and clowns, and use electrical or mechanical effects instead of real fleas.
Techniques with real fleas
Fleas typically live only for a few months and are not trained.
Fleas are observed to see if they have a predisposition for jumping or walking. Once sorted, they are harnessed by carefully wrapping a thin gold wire around the neck of the flea. Once in the harness the fleas usually stay in it for life. The harnesses are attached to the props and the strong legs of the flea allow them to move objects significantly larger than themselves.
Jumping fleas are used for kicking small lightweight balls. They are carefully given a ball; when they try to jump away (which is not possible because of the harness) they shoot the ball instead. Running fleas can pull small carts and vehicles or rotate a Ferris wheel.
There are historical reports of fleas glued to the base of the flea circus enclosure. Miniature musical instruments were then glued to the flea performers and the enclosure was heated. The fleas fought to escape, giving the impression of fleas playing instruments.
Techniques without real fleas
Some flea circuses may appear to use real fleas, but in fact do not. A variety of electrical, magnetic, and mechanical devices have been used to augment exhibits. In some cases these mechanisms are responsible for all of the "acts", with loose fleas in the exhibit maintaining the illusion. These circuses are known as "Humbug" flea circuses.
Some "flea circuses" really contain no fleas at all, and the experience and skill of the performer convince the audience of their existence.
Current flea circuses:
- Svensons Flea Circus performs in the UK and also make and sell real flea circus props and 'Humbug' flea circuses.
- Professor Hype's (Hyper the Clown) Dinky Di Aussie Flea Circus based in the Northern Territory of Australia and has been known to travel the globe.
- Professor Oddnaught's Circus Has been seen on National Geographic, Animal Planet, MTV and throughout the U.S. has made limited tours since 1997.
- Captain Franko's Fantabulous Flea Circus performed regularly in Covent Garden, London. After touring Ireland since 2005, now back in the home of street performing.Captain Franko on Facebook
- Professor A. G. Gertsacov's Acme Miniature Flea Circus performs primarily in Canada and the United States, touring numerous venues and festivals since 1995.
- The Alberti Flea Circus tours the US, and can be seen at county and state fairs and private shows.
- Dr Dillinger's Flea Circus and Caravan of Mystery has performed since 2007 in Colorado, Kansas and Oklahoma in the USA. The show is often associated with Dr Dillinger's Freaks and Floozies, a contemporary Vaudeville/Burlesque troupe.
- Phydeaux's Flying Flea Circus of Fate tours across the USA, including New York, New Jersey, Pennsylvania, Maryland and Delaware area. It also has done performances in Texas, Florida and Virginia.
- Professor Payne's Phantasmagorical Flea Circus can be seen at public libraries and private shows in the US state of Washington.
- Professor B's Flea Circus has been performing in Northern California, USA for the last few years.
- The Flying Starts Flea Circus and Sideshow tours in the UK.
- The Flohcircus Birk at the Munich Oktoberfest in Germany.
- Ms Chameleon's Incredible Flea Circus performs in London and at festivals across the UK. Ms Chameleon on Facebook 
Famous flea circuses of the past:
- María Fernanda Cardoso toured the world with her installation art flea circus in the 1990s.
- Professor Heckler's flea circus (in residence at Hubert's Dime Museum in Times Square, New York until 1957) which can be seen in the background of the film Easy Rider
- L. Bertolotto's flea circus of Regent Street, London.
- A famously televised flea circus (without fleas) was created by Michael Bentine in the 1960s.
- The Tex Avery cartoon The Flea Circus (MGM, 1954) featured a French flea circus that broke up when they saw a dog and attacked it, and one flea, Francois (voiced by Bill Thompson, better known to aficionados of such classic cartoons for providing the voice of Droopy), who played a sad clown, marries the star flea, Fifi, and has enough fleas together to bring the flea circus back to life.
- Dixieland Droopy (1954), this Tex Avery-directed animated short in the Droopy series features Droopy, as John Irving Pettybone, finding a flea band and being chased by a flea circus owner who wants the band for his circus. John Pettybone ultimately becomes the "dog of mystery," who supposedly "plays Dixieland without a band."
- Curtain Razor is a vintage Warner Bros. cartoon that has Porky Pig as a theatrical agent auditioning acts, including a shaggy dog, who turns out to be the transport of a flea circus, which proceeds to set itself up, perform, and return to the dog, on command.
- The Batfink episode "Jumping Jewelry" (1967) features Professor Hopper, an owner of a flea circus, using his trained fleas to steal jewelry.
- The Jetsons season 2 episode "Fugitive Fleas" (1985), a rock band of fleas take refuge on Astro to escape the tyrannical Solarini's flea circus.
- Flea Circus (mid-1990s) is an autobiographical comic strip by Vic Pratt.
- Mona the Vampire features a second-season episode titled "Flea Circus of Horrors," which was transmitted in 2000.
- Grimmy's Flea Circus (2001) is a book in the Mother Goose and Grimm comic strip series.
- Haunted Mansion issue 4 (August 2006) "Night of the Ghost Fleas" features Fifi, the ghost dog, being plagued by ghost fleas who create a flea circus that ends up on his head.
- The Muppet Show: The Treasure of Peg-Leg Wilson issue 3 (2009) features fleas who put on the act, Julius Prunes Amazing Flea Circus, on Animal's drums.
- Flea Circus (2010) is an animation by Graeme Meredith.
- Thundering Fleas (1926) An Our Gang film featuring Oliver Hardy and a cameo appearance by comedian Charley Chase.
- The Chimp (1932), this Laurel and Hardy short film features a flea circus given as a pay-off, which escapes into the bed, causing everyone to itch
- It's in the Bag! (1945), Fred Allen is a flea circus ringmaster
- Limelight (1952), Charlie Chaplin performing a flea circus
- Mr. Arkadin (1955), Mischa Auer plays a flea circus owner (with real fleas) in this Orson Welles film.
- Jurassic Park (1993) creator, John Hammond, explains how he used to exhibit a flealess mechanical flea circus when he was first starting out in entertainment.
- The City of Lost Children (1995) features a former circus/freak show owner, Marcello, who uses performing fleas carrying poison to assassinate people.
- A Bug's Life (1998), the Disney/Pixar film, centers on a troupe of flea circus performers, including their owner, P.T. Flea, a parody of the real-life circus entrepreneur P.T. Barnum
- The Death of the Flea Circus Director by Thomas Koerfer, a dark tale of a performer who switches from a flea circus to a play about the plague
- "Flea Circus", country song on the album Don’t You Go Chicken (1960s) by Ramblin' Tommy Scott
- "Flea Circus", grunge song on the album Step on a Bug (1988) by The U-Men
- "Flea Circus", modern creative song on the album Papa Woody (1996) by Ether Bunny
- "Flea Circus", anti-folk song on the album X-Ray Vision (1996) by The Moldy Peaches
- "Flea Circus", folk music song on the album Circle (2006) by Uiscedwr
- "Flea Circus", song by Marder in the film FAQ About Time Travel (2009)
- Neon Flea Circus, psyche-funk band based in Cork, Ireland, appeared in Solas Festival, June 2010.
- "Flea Circus", a jazz quartet led by trumpet player Jack Davies.
- "Fifi The Flea", pop/folk song on the album Would You Believe (1966) by The Hollies 
- The Flea Circus (Novella, 1950s) by Billy Lee Brammer
- Esmeralda (1954), a short story by John Wyndham, is centered around a flea circus.
- 'David Attenborogh's Natural Curiosities' 2015 features Svensons real flea circus.
- A flea circus is featured in Enid Blyton's novel The Mystery of the Missing Man (1956), which is no. 13 of her Five Find-Outers and Dog series of children's mystery stories. The book erroneously suggests that the circus works because the fleas are intelligent, and thus capable of being trained.
- McGruder's Marvels Galaxy Science Fiction July 1968 by (R.A. Lafferty)
- The Flea Circus (Islet Books, 1989) by poet Alan Pizzarelli
- Mighty Morphin Power Rangers season one episode "For Whom the Bell Trolls" (1993), reveals Bulk and Skull's hobbies include picking up fleas from stray dogs. They attempted to demonstrate their flea circus in their class' hobby week but the fleas escape onto their teacher Miss Appleby
- Round the Twist episode "Dog By Night" (2000), at a flea circus, a rare Transylvanian flea named Count Dracumite sinks its teeth into Pete, turning him into a werewolf at night
- Flea Circus, a bi-monthly event in Angel, London featuring comedy, music and poetry.
- Maxfield Rubbish and His Time Travelling Flea Circus, presented at the Hitchcock Puppet Theater in Balboa Park, San Diego, California
- "Flea Circus" (2006), Hewlett-Packard commercial produced by Bent Image Lab
- Touch Detective (2006), in episode 4 of this mystery adventure video game for the Nintendo DS, the main character, Penelope, claims that a murder happened at the flea circus.
- Flea Circus, a puzzle game on the FunOrb website, originally developed by Andrew Gower
- William Heaven's Bi-Weekly flea circus is held in both Cambridge and Newcastle upon Tyne
- Flea circus and magic by Il Mago di Londra, magician Paul Saulsbury performed at the Ca'Bianca cabaret in Milan, Italy during the 1980s.
- "Geschichte". Flohcirkus.de. Retrieved 2013-10-25.
- National Geographic, May 1988.
- Hund, Katze, Maus. 10.02.2010 VOX
- "Flea-Circus.com". Noonco.com. Retrieved 2010-08-26.
- "Welcome Page". Svensons.co.uk. Retrieved 2011-10-12.
- "Acme Flea Circus Page". TrainedFleas.com!. 2005-02-01. Retrieved 2010-08-26.
- "Alberti Flea Circus & Strolling Street Organ". Albertifleacircus.com. Retrieved 2010-08-26.
- "Professor Payne's Phantasmagorical Flea Circus". Masterpaynemagic.com. Retrieved 2010-08-26.
- "Professor B's Flea Circus". Playland-Not-At-The-Beach. Retrieved 2010-08-26.
- "The Flying Start's Flea Circus". Flea-circus.co.uk. Retrieved 2010-09-21.
- "Oktoberfest Fun Rides". Munich.mydestinationinfo.com. Retrieved 2011-10-12.
- "Ms Chameleon's Incredible Flea Circus". facebook.com/chameleonfleacircus. Retrieved 2014-09-23.
- L.Bertolotto The history of the flea
- "Thomas Koerfer filmography - The Death of a Flea Circus Director". Koerferfilm.com. Retrieved 2010-09-21.
- "Trumpet Warriors: Flea Circus". Barbican. 2011-03-03. Retrieved 2013-10-25.
- "Fifi the Flea - The Hollies | Listen, Appearances, Song Review". AllMusic. Retrieved 2013-10-25.
- Kast, Marlise. "Calendar - San Diego Magazine - February 2008 - San Diego, California". San Diego Magazine. Retrieved 2010-09-21.
- "Fleas: The Lethal Leapers". National Geographic 173 (5). May 1988.
- Jay's Journal of Anomalies, ISBN 1-59372-000-9
- Loving batbat by Gougou
- Wild Tigers & Tame Fleas by William Ballantine, (1958)
- Annals of the New York Stage by George C. Odel (Columbia University Press, New York, NY, 1928)
- Bertolotto, L. The history of the flea: With notes and observations (2nd ed.). London: Crozier.
- Bertolotto, L. (1876). The history of the flea: With notes and observations (5th ed.). New York: John Axford. OCLC 11028632.
- The Compleat Flea by Brendan Lehan (London: John Murray, 1969)
- The Faithful Annalist: Or The Epitome Of The English History (Whitwood, 1666)
- British Pathe News
- List of Historical Flea Circus Performers ShowHistory.Com
- Flea circus research and directory of current performers fleacircus.co.uk
-  "Buy a flea circus from Svensons"
- www.trainedfleas.com The Acme Miniature Flea Circus
- www.yourfleacircus.com "Buy your own Svensons Flea Circus"
- www.flea-circus.com "Build your own Flea Circus"