====== Dinosaur 'sails' ======

Several species of extinct dinosaurs independently evolved large, elaborate, sail-like structures on their backs. Examples include [[https://en.wikipedia.org/wiki/Spinosaurus|Spinosaurus]], [[https://en.wikipedia.org/wiki/Ouranosaurus|Ouranosaurus]] and [[https://en.wikipedia.org/wiki/Oxalaia|Oxalaia]].

Several other extinct animals (belonging to the Synapsid group rather than the Dinosaur clade) also had very prominent 'sails'. Examples :[[https://en.wikipedia.org/wiki/Edaphosaurus|Edaphosaurus]] , [[https://en.wikipedia.org/wiki/Dimetrodon|Dimetrodon]] and [[https://en.wikipedia.org/wiki/Secodontosaurus|Secodontosaurus]]

The function of the 'sails' has been investigated since the first days of their discovery.

Theories include :

  * As a courtship display
  * For thermo-regulation
  * For food storage
  * For camouflage
  * As a 'sound' display
  * Protection against predators
  * Wind-powered sailing over water
  * As a backbone support structure

The explanations, which are not mutually exclusive, remain highly debated.

//Note:// Several modern-day lizards and amphibians have sail-like structures -  though generally much less prominent than the dinosaurs. See list at [[https://en.wikipedia.org/wiki/Neural_spine_sail#List_of_organisms_with_a_sail|Wikipedia]]