Editing Mammal (section)

===Intelligence===
{{See also|Animal cognition}}
In intelligent mammals, such as [[primate]]s, the [[cerebrum]] is larger relative to the rest of the brain. [[Intelligence]] itself is not easy to define, but indications of intelligence include the ability to learn, matched with behavioural flexibility. [[Rat IQ|Rats]], for example, are considered to be highly intelligent, as they can learn and perform new tasks, an ability that may be important when they first colonise a fresh [[biome|habitat]]. In some mammals, food gathering appears to be related to intelligence: a deer feeding on plants has a brain smaller than a cat, which must think to outwit its prey.<ref name="Smithsonian_Animal">{{cite book | veditors = Wilson DE, Burnie D | title=Animal: The Definitive Visual Guide to the World's Wildlife| pages=86–89| publisher=DK Publishing| edition=| year =2001| isbn=978-0-7894-7764-4| oclc=46422124 }}</ref>

[[File:A Bonobo at the San Diego Zoo "fishing" for termites.jpg|thumb|A [[bonobo]] fishing for [[termite]]s with a stick]]

[[Tool use by animals]] may indicate different levels of [[learning]] and [[animal cognition|cognition]]. The [[tool use by sea otters|sea otter]] uses rocks as essential and regular parts of its foraging behaviour (smashing [[abalone]] from rocks or breaking open shells), with some populations spending 21% of their time making tools.<ref>{{cite journal | vauthors = Mann J, Patterson EM | title = Tool use by aquatic animals | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 368 | issue = 1630 | pages = 20120424 | date = November 2013 | pmid = 24101631 | pmc = 4027413 | doi = 10.1098/rstb.2012.0424 }}</ref> Other tool use, such as [[chimpanzee]]s using twigs to "fish" for termites, may be developed by [[Observational learning|watching others use tools]] and may even be a true example of animal teaching.<ref>{{cite book| vauthors = Raffaele P |year=2011 |title=Among the Great Apes: Adventures on the Trail of Our Closest Relatives |publisher=Harper |page=83 |isbn=978-0-06-167184-5 |location=New York |oclc=674694369}}</ref> Tools may even be used in solving puzzles in which the animal appears to experience a [[Eureka effect|"Eureka moment"]].<ref>{{cite book |url={{Google books|plainurl=yes|id=IIR8CgAAQBAJ}} | vauthors = Köhler W |year=1925 |publisher=Liveright |title=The Mentality of Apes |isbn=978-0-87140-108-3|oclc=2000769}}</ref> Other mammals that do not use tools, such as dogs, can also experience a Eureka moment.<ref>{{cite journal | vauthors = McGowan RT, Rehn T, Norling Y, Keeling LJ | title = Positive affect and learning: exploring the "Eureka Effect" in dogs | journal = Animal Cognition | volume = 17 | issue = 3 | pages = 577–587 | date = May 2014 | pmid = 24096703 | doi = 10.1007/s10071-013-0688-x | s2cid = 15216926 }}</ref>

[[Brain size]] was previously considered a major indicator of the intelligence of an animal. Since most of the brain is used for maintaining bodily functions, greater ratios of [[Brain-to-body mass ratio|brain to body mass]] may increase the amount of brain mass available for more complex cognitive tasks. [[Allometric]] analysis indicates that mammalian brain size scales at approximately the {{frac|2|3}} or {{frac|3|4}} exponent of the body mass. Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides an [[encephalization quotient|encephalisation quotient]] that can be used as another indication of animal intelligence.<ref>{{cite journal | vauthors = Karbowski J | title = Global and regional brain metabolic scaling and its functional consequences | journal = BMC Biology | volume = 5 | issue = 18 | pages = 18 | date = May 2007 | pmid = 17488526 | pmc = 1884139 | doi = 10.1186/1741-7007-5-18 | bibcode = 2007arXiv0705.2913K | arxiv = 0705.2913 | doi-access = free }}</ref> [[Sperm whale]]s have the largest brain mass of any animal on earth, averaging {{convert|8000|cm3}} and {{convert|7.8|kg}} in mature males.<ref>{{cite journal | vauthors = Marino L | title = Cetacean brains: how aquatic are they? | journal = Anatomical Record | volume = 290 | issue = 6 | pages = 694–700 | date = June 2007 | pmid = 17516433 | doi = 10.1002/ar.20530 | s2cid = 27074107 | url = https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1006&context=anatom | doi-access = free | access-date = 5 October 2019 | archive-date = 20 March 2020 | archive-url = https://web.archive.org/web/20200320082257/https://animalstudiesrepository.org/cgi/viewcontent.cgi?article=1006&context=anatom | url-status = live }}</ref>

[[Self-awareness]] appears to be a sign of abstract thinking. Self-awareness, although not well-defined, is believed to be a precursor to more advanced processes such as [[metacognition|metacognitive reasoning]]. The traditional method for measuring this is the [[mirror test]], which determines if an animal possesses the ability of self-recognition.<ref>{{cite journal | vauthors = Gallop GG | title = Chimpanzees: self-recognition | journal = Science | volume = 167 | issue = 3914 | pages = 86–87 | date = January 1970 | pmid = 4982211 | doi = 10.1126/science.167.3914.86 | bibcode = 1970Sci...167...86G | s2cid = 145295899 }}</ref> Mammals that have passed the mirror test include [[Asian elephant]]s (some pass, some do not);<ref>{{cite journal | vauthors = Plotnik JM, de Waal FB, Reiss D | title = Self-recognition in an Asian elephant | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 103 | issue = 45 | pages = 17053–17057 | date = November 2006 | pmid = 17075063 | pmc = 1636577 | doi = 10.1073/pnas.0608062103 | url = https://www.emory.edu/LIVING_LINKS/publications/articles/Plotnik_etal_2006.pdf | bibcode = 2006PNAS..10317053P | doi-access = free | access-date = 25 January 2024 | archive-date = 25 January 2024 | archive-url = https://web.archive.org/web/20240125191350/https://www.emory.edu/LIVING_LINKS/publications/articles/Plotnik_etal_2006.pdf | url-status = live }}</ref> chimpanzees;<ref name=robert>{{cite journal | vauthors = Robert S |title=Ontogeny of mirror behavior in two species of great apes |journal=American Journal of Primatology |volume=10 |issue=2 |pages=109–117 |year=1986 |doi=10.1002/ajp.1350100202 |pmid=31979488|s2cid=85330986 }}</ref> [[bonobo]]s;<ref>{{cite journal| vauthors = Walraven V, van Elsacker L, Verheyen R |year=1995 |title=Reactions of a group of pygmy chimpanzees (Pan paniscus) to their mirror images: evidence of self-recognition |journal=Primates |volume=36 |pages=145–150 |doi=10.1007/bf02381922|s2cid=38985498 }}</ref> [[orangutan]]s;<ref name=orangutan>{{cite book|chapter-url={{Google books |plainurl=yes |id=5ywsREEZ-j4C|page=150}} | vauthors = Leakey R |year=1994 |chapter=The Origin of the Mind |title=The Origin Of Humankind |location=New York |publisher=BasicBooks |page=150 |isbn=978-0-465-05313-1 |oclc=30739453}}</ref> humans, from 18 months ([[mirror stage]]);<ref name="archer">{{cite book | vauthors = Archer J |year=1992 |title=Ethology and Human Development |publisher=Rowman & Littlefield |pages=215–218 |isbn=978-0-389-20996-6 |oclc=25874476 |url={{Google books |plainurl=yes |id=QDT27k5envcC|page=217}}}}</ref> [[common bottlenose dolphin]]s;{{efn|Decreased latency to approach the mirror, repetitious head circling and close viewing of the marked areas were considered signs of self-recognition since they do not have arms and cannot touch the marked areas.<ref name=parker95/>}}<ref name=parker95>{{cite book |title=Self-awareness in Animals and Humans: Developmental Perspectives | vauthors = Marten K, Psarakos S |chapter=Evidence of self-awareness in the bottlenose dolphin (''Tursiops truncatus'') | veditors = Parker ST, Mitchell R, Boccia M |pages=361–379 |year=1995|location=Cambridge|publisher=Cambridge University Press |isbn=978-0-521-44108-7 |oclc=28180680}}</ref> [[orca]]s;<ref name="Delfour">{{cite journal | vauthors = Delfour F, Marten K | title = Mirror image processing in three marine mammal species: killer whales (Orcinus orca), false killer whales (Pseudorca crassidens) and California sea lions (Zalophus californianus) | journal = Behavioural Processes | volume = 53 | issue = 3 | pages = 181–190 | date = April 2001 | pmid = 11334706 | doi = 10.1016/s0376-6357(01)00134-6 | s2cid = 31124804 }}</ref> and [[false killer whale]]s.<ref name=Delfour/>