Editing Ardipithecus (section)

== Paleobiology ==
The ''Ardipithecus'' length measures are good indicators of function and together with dental isotope data and the fauna and flora from the fossil site indicate ''Ardipithecus'' was mainly a terrestrial quadruped collecting a large portion of its food on the ground. Its arboreal behaviors would have been limited and suspension from branches solely from the upper limbs rare.<ref name=Sarmiento2011/> A comparative study in 2013 on carbon and oxygen stable isotopes within modern and fossil [[tooth enamel]] revealed that ''Ardipithecus'' fed both [[Arboreal locomotion|arboreally]] (on trees) and on the ground in a more open habitat, unlike chimpanzees.<ref>{{cite journal |last=Nelson |first=Sherry V. |year=2013 |title=Chimpanzee fauna isotopes provide new interpretations of fossil ape and hominin ecologies |journal=Proceedings of the Royal Society B: Biological Sciences |volume=280 |issue=1773 |pages=20132324 |doi=10.1098/rspb.2013.2324 |pmc=3826229 |pmid=24197413}}</ref>

In 2015, Australian anthropologists Gary Clark and Maciej Henneberg said that ''Ardipithecus'' adults have a facial anatomy more similar to chimpanzee subadults than adults, with a less-projecting face and smaller canines (large canines in primate males are used to compete within mating hierarchies), and attributed this to a decrease in craniofacial growth in favour of brain growth. This is only seen in humans, so they argued that the species may show the first trend towards human social, parenting and sexual psychology.<ref name="Clark & Henneberg 2015"/> Previously, it was assumed that such ancient human ancestors behaved much like chimps, but this is no longer considered to be a viable comparison.<ref>{{cite journal |doi=10.1146/annurev-anthro-092611-145815 |ssrn=2158266 |title=Human Evolution and the Chimpanzee Referential Doctrine |journal=Annual Review of Anthropology |volume=41 |pages=119–38 |year=2012 |last1=Sayers |first1=Ken |last2=Raghanti |first2=Mary Ann |last3=Lovejoy |first3=C. Owen }}</ref> This view has yet to be corroborated by more detailed studies of the growth of ''A. ramidus''. The study also provides support for [[Stephen Jay Gould]]'s theory in [[Ontogeny and Phylogeny (book)|''Ontogeny and Phylogeny'']] that the paedomorphic (childlike) form of early hominin craniofacial morphology results from dissociation of growth trajectories.

Clark and Henneberg also argued that such shortening of the skull—which may have caused a descension of the [[larynx]]—as well as lordosis—allowing better movement of the larynx—increased vocal ability, significantly pushing back the [[origin of language]] to well before the evolution of ''Homo''. They argued that self domestication was aided by the development of vocalization, living in a pro-social society. They conceded that chimps and ''A. ramidus'' likely had the same vocal capabilities, but said that ''A. ramidus'' made use of more complex vocalizations, and vocalized at the same level as a human infant due to [[selective pressure]] to become more social. This would have allowed their society to become more complex. They also noted that the base of the skull stopped growing with the brain by the end of juvenility, whereas in chimps it continues growing with the rest of the body into adulthood; and considered this evidence of a switch from a gross skeletal anatomy trajectory to a neurological development trajectory due to selective pressure for sociability. Nonetheless, their conclusions are highly speculative.<ref>{{cite journal|first1=G.|last1=Clark|first2=M.|last2=Henneberg|year=2017|title=''Ardipithecus ramidus'' and the evolution of language and singing: An early origin for hominin vocal capability|journal=Homo|volume=68|issue=2|pages=101–121|doi=10.1016/j.jchb.2017.03.001|pmid=28363458}}</ref><ref name="Clark & Henneberg 2015">{{cite journal |doi=10.1515/anre-2015-0009 |title=The life history of Ardipithecus ramidus: A heterochronic model of sexual and social maturation |journal=Anthropological Review |volume=78 |issue=2 |pages=109–132|year=2015 |last1=Clark |first1=Gary |last2=Henneberg |first2=Maciej |doi-access=free }}</ref>

According to [[Scott Simpson (anthropologist)|Scott Simpson]], the Gona Project's [[biological anthropology|physical anthropologist]], the fossil evidence from the [[Middle Awash]] indicates that both ''A. kadabba'' and ''A. ramidus'' lived in "a mosaic of woodland and grasslands with lakes, swamps and springs nearby," but further research is needed to determine which habitat ''Ardipithecus'' at Gona preferred.<ref name="stoneageinstitute.org"/>