Editing Cerebrospinal fluid (section)

==Other animals==
During [[phylogenesis]], CSF is present within the [[neuraxis]] before it circulates.<ref name="SAKKA2011"/> The CSF of [[teleost]] fish, which do not have a subarachnoid space, is contained within the ventricles of their brains.<ref name="SAKKA2011"/> In mammals, where a subarachnoid space is present, CSF is present in it.<ref name="SAKKA2011"/> Absorption of CSF is seen in [[amniote]]s and more complex species, and as species become progressively more complex, the system of absorption becomes progressively more enhanced, and the role of spinal epidural veins in absorption plays a progressively smaller and smaller role.<ref name="SAKKA2011"/>

The amount of cerebrospinal fluid varies by size and species.<ref name="REECE2013">{{cite book|last1=Reece|first1=William O. | name-list-style = vanc |title=Functional Anatomy and Physiology of Domestic Animals|date=2013|publisher=John Wiley & Sons|isbn=978-1-118-68589-1|page=118|url=https://books.google.com/books?id=C_q3Q-IpkNMC&q=cerebrospinal+fluid+and+animals&pg=PA118|language=en}}</ref> In humans and other [[mammal]]s, cerebrospinal fluid turns over at a rate of 3–5 times a day.<ref name=REECE2013 /> Problems with CSF circulation, leading to hydrocephalus, can occur in other animals as well as humans.<ref name=REECE2013 />