Editing Remora (section)

== Physiology ==
Research into the [[physiology]] of the remora has been of significant benefit to the understanding of [[Ventilation (physiology)|ventilation]] costs in fish.

Remoras, like many other fishes, have  two different modes of ventilation. Ram ventilation<ref name="Willmer">{{Cite book|url=https://books.google.com/books?id=r9gvbjRFyRgC|title=Environmental Physiology of Animals|last1=Willmer|first1=Pat|last2=Stone|first2=Graham|last3=Johnston|first3=Ian|date=2009-03-12|publisher=John Wiley & Sons|isbn=978-1-4443-0922-5|language=en}}</ref> is the process in which at higher speeds, the remora uses the force of the water moving past it to create movement of fluid in the gills. At lower speeds, the remora will use a form of active ventilation,<ref name="Willmer" /> in which the fish actively moves fluid through its gills. In order to use active ventilation, a fish must actively use energy to move the fluid; however, determining this energy cost is normally complicated due to the fish's movement when using either method. As a result, the remora has proved invaluable in finding this cost difference (since they will stick to a shark or tube, and hence remain stationary despite the movement, or lack thereof, of water). Experimental data from studies on remora found that the associated cost for active ventilation created a 3.7–5.1% increased energy consumption in order to maintain the same quantity of fluid flow the fish obtained by using ram ventilation.<ref>{{Cite journal|last1=Steffensen|first1=J. F.|last2=Lomholt|first2=J. P.|date=1983-03-01|title=Energetic cost of active branchial ventilation in the sharksucker, ''Echeneis naucrates''|url=http://jeb.biologists.org/content/103/1/185|journal=Journal of Experimental Biology|language=en|volume=103|issue=1|pages=185–192|doi=10.1242/jeb.103.1.185 |issn=0022-0949|pmid=6854201|url-access=subscription}}</ref>

Other research into the remora's physiology came about as a result of studies across multiple taxa, or using the remora as an out-group for certain evolutionary studies. Concerning the latter case, remoras were used as an outgroup when investigating [[tetrodotoxin]] resistance in remoras, pufferfish, and related species, finding remoras (specifically ''[[Echeneis naucrates]]'') had a resistance of 6.1–5.5{{e|-8}}&nbsp;M.<ref>{{cite journal|doi=10.1007/BF00696163|title=Tetrodotoxin sensitivity of muscle action potentials in pufferfishes and related fishes|journal=Journal of Comparative Physiology|volume=89|pages=59–72|year=1974|last1=Kidokoro|first1=Yoshiaki|last2=Grinnell|first2=Alan D.|last3=Eaton|first3=Douglas C.|s2cid=33178106 }}</ref>