Editing Elephant (section)

=== Internal systems ===
The brain of an elephant weighs {{convert|4.5|–|5.5|kg|lb|0|abbr=on}} compared to {{convert|1.6|kg|lb|0|abbr=on}} for a human brain.<ref name=Shoshani78 /> It is the largest of all terrestrial mammals.<ref name="posse">{{cite book|author=O'Connell, Caitlin|title="Elephant Don: The Politics of a Pachyderm Posse"|date=20 July 2016|publisher=University of Chicago Press |isbn=9780226380056|url=https://books.google.com/books?id=2ZElEAAAQBAJ&q=Elephants+have+the+largest+temporal+lobe+relative+to+the+size+of+its+body+among+any+land+mammals&pg=PA102|access-date=16 September 2022|archive-date=21 March 2023|archive-url=https://web.archive.org/web/20230321084756/https://books.google.com/books?id=2ZElEAAAQBAJ&q=Elephants+have+the+largest+temporal+lobe+relative+to+the+size+of+its+body+among+any+land+mammals&pg=PA102|url-status=live}}</ref> While the elephant brain is larger overall, it is [[Encephalization quotient|proportionally smaller than the human brain]]. At birth, an elephant's brain already weighs 30–40% of its adult weight. The [[cerebrum]] and [[cerebellum]] are well developed, and the [[temporal lobe]]s are so large that they bulge out laterally.<ref name=Shoshani78 /> Their temporal lobes are proportionally larger than those of other animals, including humans.<ref name=posse /> The throat of an elephant appears to contain a pouch where it can store water for later use.<ref name=evolution /> The [[larynx]] of the elephant is the largest known among mammals. The [[vocal fold]]s are anchored close to the [[epiglottis]] base. When comparing an elephant's vocal folds to those of a human, an elephant's are proportionally longer, thicker, with a greater cross-sectional area. In addition, they are located further up the vocal tract with an acute slope.<ref name="vibratorypatterns">{{cite journal|author1= Herbest, C. T.| author2 = Švec, J. G.| author3 = Lohscheller, J.| author4 = Frey, R.| author5 = Gumpenberger, M.| author6 = Stoeger, A.| author7 = Fitch, W. T.|year=2013|title= Complex Vibratory Patterns in an Elephant Larynx|journal= Journal of Experimental Biology|volume=216|issue=21|pages=4054–4064|doi=10.1242/jeb.091009
|pmid=24133151|doi-access=free}}</ref>
[[File:Em - Loxodonta africana heart - GMZ 2.jpg|thumb|right|African elephant heart in a jar]]
The heart of an elephant weighs {{convert|12|–|21|kg|lb|abbr=on}}. Its [[Heart#Location and shape|apex]] has two pointed ends, an unusual trait among mammals.<ref name=Shoshani78 /> In addition, the [[Ventricle (heart)|ventricles]] of the heart split towards the top, a trait also found in sirenians.<ref name="Marshall Cavendish">{{cite book| author=Anon|title=Mammal Anatomy: An Illustrated Guide |year=2010 |publisher=Marshall Cavendish |isbn=978-0-7614-7882-9 |page=59}}</ref> When upright, the elephant's heart beats around 28 beats per minute and actually speeds up to 35 beats when it lies down.<ref name=Shoshani78/> The blood vessels are thick and wide and can hold up under high blood pressure.<ref name="Marshall Cavendish"/> The lungs are attached to the [[Thoracic diaphragm|diaphragm]], and breathing relies less on the expanding of the ribcage.<ref name=Shoshani78>Shoshani, pp. 78–79.</ref> [[Connective tissue]] exists in place of the [[pleural cavity]]. This may allow the animal to deal with the pressure differences when its body is underwater and its trunk is breaking the surface for air.<ref name="snorkel">{{cite journal|author=West, J. B.|s2cid=27321751|year=2002|title=Why doesn't the elephant have a pleural space?|journal=Physiology|volume=17|issue=2|pages=47–50|pmid=11909991|doi=10.1152/nips.01374.2001|doi-access=free}}</ref> Elephants breathe mostly with the trunk but also with the mouth. They have a [[hindgut fermentation]] system, and their large and small intestines together reach {{convert|35|m|ft|0|abbr=on}} in length. Less than half of an elephant's food intake gets digested, despite the process lasting a day.<ref name=Shoshani78 /> An elephant's bladder can store up to 18 litres of urine<ref>{{Cite journal |last1=Yang |first1=Patricia J. |last2=Pham |first2=Jonathan |last3=Choo |first3=Jerome |last4=Hu |first4=David L. |date=2014-08-19 |title=Duration of urination does not change with body size |journal=Proceedings of the National Academy of Sciences |language=en |volume=111 |issue=33 |pages=11932–11937 |doi=10.1073/pnas.1402289111 |doi-access=free |issn=0027-8424 |pmc=4143032 |pmid=24969420|bibcode=2014PNAS..11111932Y }}</ref> and its [[kidneys]] can produce more than 50 [[litre]]s of urine per day.<ref name="FowlerMikota2006" />