Human

=== Sleep and dreaming ===
{{Main|Sleep|Dream}}
Humans are generally [[Diurnality|diurnal]]. The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though [[sleep deprivation]] can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort.<ref name=Grandner2010>{{cite journal | vauthors = Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI | title = Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies | journal = Sleep Medicine Reviews | volume = 14 | issue = 4 | pages = 239–247 | date = August 2010 | pmid = 19896872 | pmc = 2888649 | doi = 10.1016/j.smrv.2009.08.001 }}</ref><!--cites previous two sentences-->

During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the [[pons]] and mostly occurs during the [[REM phase of sleep]].<ref>{{cite web| vauthors = Ann L |date=27 January 2005|title=HowStuffWorks "Dreams: Stages of Sleep"|url=https://science.howstuffworks.com/environmental/life/human-biology/dream2.htm|url-status=dead|archive-url=https://web.archive.org/web/20120515212353/https://science.howstuffworks.com/environmental/life/human-biology/dream2.htm|archive-date=15 May 2012|access-date=11 August 2012|publisher=Science.howstuffworks.com}}</ref> The length of a dream can vary, from a few seconds up to 30 minutes.<ref name=Hobson>{{cite journal | vauthors = Hobson JA | title = REM sleep and dreaming: towards a theory of protoconsciousness | journal = Nature Reviews. Neuroscience | volume = 10 | issue = 11 | pages = 803–813 | date = November 2009 | pmid = 19794431 | doi = 10.1038/nrn2716 | s2cid = 205505278 }}</ref> Humans have three to five dreams per night, and some may have up to seven.<ref>{{cite book | vauthors = Empson J | date = 2002 | title = Sleep and dreaming | edition = 3rd | location = New York | publisher = Palgrave/St. Martin's Press }}</ref> Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of [[lucid dream]]ing, where the dreamer is [[self-aware]].<ref>{{cite web| vauthors = Lite J |date=29 July 2010|title=How Can You Control Your Dreams?|url=https://www.scientificamerican.com/article/how-to-control-dreams/|url-status=live|archive-url=https://web.archive.org/web/20150202070145/https://www.scientificamerican.com/article/how-to-control-dreams/|archive-date=2 February 2015|website=Scientific America}}</ref> Dreams can at times make a [[Creativity|creative]] thought occur or give a sense of [[Artistic inspiration|inspiration]].<ref>{{cite book | vauthors = Domhoff W | date = 2002 | title = The scientific study of dreams | publisher = APA Press }}</ref>