Neanderthals behaved not so differently from us in
raising their children, whose pace of growth was similar to Homo sapiens.
Thanks to the combination of geochemical and histological analyses of three
Neanderthal milk teeth, researchers were able to determine their pace of growth
and the weaning onset time. These teeth belonged to three different Neanderthal
children who have lived between 70,000 and 45,000 years ago in a small area of
northeastern Italy.
FRANKFURT/KENT/BOLOGNA/FERRARA. Teeth
grow and register information in form of growth lines, akin to tree rings, that
can be read through histological techniques. Combining such information with
chemical data obtained with a laser-mass spectrometer, in particular strontium
concentrations, the scientists were able to show that these Neanderthals
introduced solid food in their children's diet at around 5-6 months of age.
Not cultural but physiological
Alessia Nava (University of Kent, UK),
co-first author of the work, says: “The beginning of weaning relates to
physiology rather than to cultural factors. In modern humans, in fact, the
first introduction of solid food occurs at around 6 months of age when the
child needs a more energetic food supply, and it is shared by very different
cultures and societies. Now, we know that also Neanderthals started to wean
their children when modern humans do".
“In particular, compared to other
primates" says Federico Lugli (University of Bologna), co-first author of the
work “it is highly conceivable that the high energy demand of the growing human
brain triggers the early introduction of solid foods in child diet".
Neanderthals are our closest cousins
within the human evolutionary tree. However, their pace of growth and early
life metabolic constraints are still highly debated within the scientific
literature.
Stefano Benazzi (University of Bologna),
co-senior author, says: “This work's results imply similar energy demands
during early infancy and a close pace of growth between Homo sapiens and
Neanderthals. Taken together, these factors possibly suggest that Neanderthal
newborns were of similar weight to modern human neonates, pointing to a likely
similar gestational history and early-life ontogeny, and potentially shorter
inter-birth interval".
Home, sweet home
Other than their early diet and growth,
scientists also collected data on the regional mobility of these Neanderthals
using time-resolved strontium isotope analyses.
“They were less mobile than previously
suggested by other scholars" says Wolfgang Müller (Goethe University
Frankfurt), co-senior author “the strontium isotope signature registered in
their teeth indicates in fact that they have spent most of the time close to
their home: this reflects a very modern mental template and a likely thoughtful
use of local resources".
“Despite the general cooling during the
period of interest, Northeastern Italy has almost always been a place rich in
food, ecological variability and caves, ultimately explaining survival of
Neanderthals in this region till about 45,000 years ago" says Marco Peresani
(University of Ferrara), co-senior author and responsible for findings from
archaeological excavations at sites of De Nadale and Fumane.
This research adds a new piece in the
puzzling pictures of Neanderthal, a human species so close to us but still so
enigmatic. Specifically, researchers exclude that the Neanderthal small
population size, derived in earlier genetic analyses, was driven by differences
in weaning age, and that other biocultural factors led to their demise. This
will be further investigated within the framework of the ERC project SUCCESS
('The Earliest Migration of Homo sapiens in Southern Europe - Understanding the
biocultural processes that define our uniqueness'), led by Stefano Benazzi at
University of Bologna.
Publication: Alessia Nava, Federico Lugli, Matteo Romandini, Federica Badino, David Evans, Angela H. Helbling, Gregorio Oxilia, Simona Arrighi, Eugenio Bortolini, Davide Delpiano, Rossella Duches, Carla Figus, Alessandra Livraghi, Giulia Marciani, Sara Silvestrini, Anna Cipriani, Tommaso Giovanardi, Roberta Pini, Claudio Tuniz, Federico Bernardini, Irene Dori, Alfredo Coppa, Emanuela Cristiani, Christopher Dean, Luca Bondioli, Marco Peresani, Wolfgang Müller, Stefano Benazzi, Early life of Neanderthals. Proceedings of the National Academy of Sciences Oct 2020, DOI: 10.1073/pnas.2011765117
Picture
downloads:
1.
Fumane Cave near Verona (Wikipedia): This is where several of the
milk teeth of Neanderthal children investigated by Professor Wolfgang Müller at
Goethe University were found. https://de.wikipedia.org/wiki/Grotta_di_Fumane#/media/Datei:Grotta_di_Fumane_3.jpg
2.
Neanderthal milk teeth: Presumably a Neanderthal child lost this
tooth 40,000 to 70,000 year ago when his or her permanent teeth came in.
Credit: ERC project SUCCESS, University of Bologna, Italy
http://www.uni-frankfurt.de/93639226
3.
Ultra-thin cut: Researchers at Goethe University cut
paper-thin slices off of a Neanderthal milk tooth. The teeth are subsequently
put back together and reconstructed. Credit/video still: Luca Bondioli and
Alessia Nava, Rome, Italy
http://www.uni-frankfurt.de/93639334
Further
information:
Professor Wolfgang
Müller
Institute for Geosciences /
Frankfurt Isotope and Element Research Center (FIERCE)
Tel. +49 (0)69 798 40291,
w.muller@em.uni-frankfurt.de
http://www.uni-frankfurt.de/49540288/Homepage-Mueller