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The first human ancestors have breastfed longer than their present relatives



<div data-thumb = "https://scx1.b-cdn.net/csz/news/tmb/2019/firsthumanan.jpg" data-src = "https://scx2.b-cdn.net /gfx/news/hires/2019/firsthumanan.jpg "data-sub-html =" The differences in tooth morphology are evident between Australopithecus africanus (TM1518 left) and early homo (SK27 right)), but these teeth also differ in their calcium-stable isotopic compositions and reveal group-specific quiescence. "Credit: Vincent Balter">

<img src = "https://scx1.b-cdn.net/csz/news/800/2019/firsthumanan.jpg" alt = "First human ancestors breastfed longer than today's relatives" title = "The differences in tooth morphology are evident between Australopithecus africanus (TM1
518 left) and early homo (SK27 right), but these teeth also differ in their calcium-stable isotopic compositions and reveal group-specific silent behavior "/>
The differences in dental morphology are evident between Australopithecus africanus (TM1518 left) and early homo (SK27 right), but these teeth also differ in their calcium-stable isotopic compositions and reveal group-specific silent behavior. Picture credits: Vincent Balter

By analyzing the fossilized teeth of some of our oldest ancestors, a team of scientists led by the universities of Bristol (UK) and Lyon (France) discovered that the first humans had breastfed their infants significantly longer than today.

The results, published in the journal Science Advances provide a first insight into the practice of sedimentation, which is otherwise unseen in the fossil record.

The team studied minute amounts of nearly 40 fossilized teeth of our South African fossil relatives, early Homo, Paranthropus robustus and Australopithecus africanus.

They measured the proportions of their stable calcium isotopes in the enamel, which are a function of breast milk intake by infants.

By Reconstruction In the age of enamel development, they showed that early homozygous offspring were breastfed in considerable proportions until about three to four years of age, which probably played a role in the development of features common to human Descent are specific, such. B. the development of the brain.

In contrast, infants of Paranthropus robustus, which became extinct about a million years ago and were also more robust in tooth anatomy than infants of Australopithecus africanus, stopped eating significant levels of breast milk in the first few months of life.

These differences in care behavior are likely to result in significant changes in the social structures of groups as well as the time between birth of one child and the birth of the next.

One of the main authors of the study, dr. Theo Tacail from Bristol University's School of Earth Sciences said: "The practice of weaning – length of breastfeeding, age of non-born – dairy food introduction and age of infant cessation – differs among modern members of the hominid family, to humans and modern ones Apes include: orangutans, gorillas, chimpanzees, and bonobos roles in the evolution of members of human descent, which are associated, for example, with the size and structure of social groups, brain development, or demographics.

The Investigation These changes in the behavior of millions of years old fossils are a challenge, and so far there are few indications that allow a discussion of the care practices of these fossil species.

"The results underscore the need for further research on isotopic compositions in calcium stable fossils to understand the coevolution of weaning practices with other characteristics such as brain size or social behavior. "


Extinct human species, which was probably breastfed one year after birth, suggests a study


Further information:
Théo Tacail et al., Calcium isotope patterns in tooth enamel reflect the different behavior of South African early hominin in nursing (19459015). Science Advances (19459016) (2019). DOI: 10.1126 / sciadv.aax3250

Provided by
University of Bristol




Quote :
First human ancestors breastfeed longer than contemporary relatives (2019, August 29)
retrieved on August 29, 2019
from https://phys.org/news/2019-08-human-ancestors-breastfed-longer-contemporary.html

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