Editing Flea (section)

===Jumping===
Their legs are long, the hind pair well adapted for jumping; a flea can jump vertically up to {{convert|18|cm|in|frac=2|abbr=off}} and horizontally up to {{convert|33|cm|in|frac=2|abbr=on}},<ref name=Crosby>{{cite web |url=http://vetmedicine.about.com/od/parasites/f/FAQ_fleacycle.htm |title=What is the Life Cycle of the Flea? |author=Crosby, J.T. |work=Veterinary Parasites |publisher=About Home |access-date=4 November 2016 |archive-date=19 September 2005 |archive-url=https://web.archive.org/web/20050919195615/http://vetmedicine.about.com/od/parasites/f/FAQ_fleacycle.htm |url-status=dead }}</ref> making the flea one of the best jumpers of all known animals (relative to body size), second only to the [[froghopper]]. A flea can jump 60 times its length in height and 110 times its length in distance, equivalent to a {{convert|1.8|m|ft|frac=2|abbr=on}} adult human jumping {{convert|110|m|ft|frac=2|abbr=on}} vertically and {{convert|200|m|ft|frac=2|abbr=on}} horizontally. Rarely do fleas jump from dog to dog. Most flea infestations come from newly developed fleas from the pet's environment.<ref>{{cite web |title=Fleas and Ticks: Facts about Fleas |url=https://www.mypet.com/fleas-and-ticks/facts-about-fleas.aspx#:~:text=A%20flea%20can%20jump%20more,fleas%20from%20the%20pet's%20environment. |website=mypet |publisher=Merck Animal Health |access-date=21 March 2022}}</ref> The flea jump is so rapid and forceful that it exceeds the capabilities of muscle, and instead of relying on direct muscle power, fleas store muscle energy in a pad of the elastic protein named [[resilin]] before releasing it rapidly (like a human using a bow and arrow).<ref name="sciencenews.org"/>  Immediately before the jump, muscles contract and deform the resilin pad, slowly storing energy which can then be released extremely rapidly to power leg extension for propulsion.<ref name=JEB>{{cite journal|last1= Burrows|first1=M.|title =How Fleas Jump|journal =Journal of Experimental Biology|volume =212|issue =18|year= 2009|pages= 2881–2883|doi= 10.1242/jeb.022855|pmid=19717668|doi-access=free}}</ref>  To prevent premature release of energy or motions of the leg, the flea employs a "catch mechanism".<ref name=JEB />  Early in the jump, the tendon of the primary jumping muscle passes slightly behind the coxa-trochanter joint, generating a [[torque]] which holds the joint closed with the leg close to the body.<ref name=JEB />  To trigger jumping, another muscle pulls the tendon forward until it passes the joint axis, generating the opposite torque to extend the leg and power the jump by release of stored energy.<ref name=JEB /> The actual take off has been shown by high-speed video to be from the tibiae and tarsi rather than from the [[Arthropod leg#Trochanter|trochantera]] (knees).<ref name="sciencenews.org">{{cite magazine |url=http://www.sciencenews.org/view/generic/id/69664/title/Fleas_leap_from_feet%2C_not_knees |title=Fleas leap from feet, not knees |magazine=Science News |date=2 October 2011 |access-date=11 November 2016 |archive-date=8 August 2011 |archive-url=https://web.archive.org/web/20110808003410/http://www.sciencenews.org/view/generic/id/69664/title/Fleas_leap_from_feet,_not_knees |url-status=dead }}</ref>