Lucy had an ape-like brain: Endocranial imprints of Australopithecus afarensis revealed they had an ape-like brain organization. Evidence was also found of protracted brain growth, which suggests infants may have had a longer dependence on caregivers
When the small-bodied, small-brained hominin was discovered in late November 1974 in Ethiopia, it paved the way to understanding that our early human relatives habitually walked on two legs. Experts have studied this skeleton of a small female, nicknamed Lucy, which provided valuable information that they had brains that were 20% larger than those of chimpanzees, and they may have used sharp tools.
Zeresenay Alemseged from the University of Chicago said that their new results on their study regarding the brains of Lucy's species Australopithecus afarensis show how their brains developed, and how they were organized. Alemseged directs the Dikka field project in Ethiopia, where the skeleton of an Australopithecus child was found in 2000.
Dikka Child
The fossils of the 'Dikka child' that Alemseged and his team found played a pivotal role in allowing paleoanthropologists to ask and answer many significant questions on how people became human. Alemseged stated, "We can now say the organization of the brain was more ape-like."
According to the news outlet Daily Mail, the researchers used Salem -a scanning technology- to analyze the skull of the 'Dikka Child' that lived about 3.3 million years ago in Ethiopia, and the device also scans Lucy and other fossils from Hadar in Ethiopia.
Named after the place it was discovered in Dikka, Ethiopia, the 'Dikka Child' is the earliest child ancestor found so far. Just like Lucy, the 'Dikka Child' belongs to the same species of Australopithecus afarensis.
It took years for the researchers to yield a well-preserved brain imprint of the Dikka Child, and knowing it's precise and age through fossil reconstruction, and counting of dental growth. Based on her dental records, the team's experts calculated that the female child lived for 861 days or equivalent to 2.4 years.
Read: Female Mammals Live Longer Than Their Human Counterparts
Differences in Brain Organization
Since brains do not fossilize, scientists rely on the imprints that these early humans leave in their skulls, which reveals information about the structure and development of their brains.
The team of researchers found the location of a fissure that separates the anterior and posterior parts of the brain closer to the front of the brain in A. afarensis, just like chimpanzees. But in humans, this fissure called the lunate sulcus, is pushed further down in the brain.
This brain reorganization in A. afarensis could have been connected to behaviors that were more complex than those of their great ape relatives in terms of making tools, thinking, and vocal communication. Unfortunately, there is an unresolved controversy about its position A. afarensis since the lunate sulcus typically does not reproduce well on endocasts.
Extended childhood
Contrary to previous claims, A. afarensis' endocrinal imprints show no features derived towards humans, but rather it reveals an ape-like brain organization. The brains of modern humans are organized differently and are larger than humans' closest living ape relatives, and it also takes longer to grow and mature.
Human infants learn longer and can be dependent on parental care for a longer period, unlike chimpanzees. These characteristics are essential for human cognition and social behavior; however, their evolutionary origins are still unclear.
Also Read: Was Prehistoric Earth Warmer Than We Thought? Evidence of Ancient Rainforests Found in South Pole
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