this grandmother was able to walk upright and climb trees with ease

little fossilized foot, no bigger than a human thumb, revealed a few -a physical abilities of A. afarensis and its possible behaviors, according to a new study published in Science Advances .

Scientists have known for a long time, or at least suspect, that the A. afarensis a hominid resembling a primitive monkey that existed somewhere in our genealogical tree (either directly or through closely related species), walked on two feet. In fact, some scientists have even suggested that these ancient great apes were exclusively bipedal, completely giving up their ancestry in favor of the heel-toe. The new study, led by Jeremy DeSilva of Dartmouth College in the United States, reveals that the young children of A. afarensis were able to stand up and walk upright. However, these young hominids also retained the ability to climb, an important physical attribute that may have helped them to hang on to their mothers, climb trees and escape predators.

Zeresenay Alemseged, professor of organic biology and anatomy at the University of Chicago and co-author of the study, found in 2002 the partial fossilized remains of a baby, died two and a half years later. age, in the Dikika region of Ethiopia. The remains of Dikika's daughter, also known as "Selam", consisted of a skull, an almost complete spine with ribs, shoulder bones, parts of her arms and legs and foot, which is the most complete foot of an ancient child ever discovered.

"Most fossil recordings are made up of adults; it is unusual to find fossilized remains of children, and these give us a wonderful insight into the growth and development of our ancestors" , said DeSilva to Gizmodo

The fossil was identified as belonging to the hominid . afarensis (same species as the famous Lucy fossil) and dated 3.32 The study adds more data to the initial analysis of 2006, since many parts of the skeleton, including the foot, have been encapsulated in sediments. already been exposed, allowing further analysis of the young specimen.

The foot analysis of the daughter Dikika suggests that the baby already possessed the bone structure necessary to stand and walk, a finding compatible with what anths Ropologists have determined in the past by studying traces found in Laetoli, Tanzania, and Lucy's fossil, an adult A. afarensis found in Hadar, Ethiopia. But the foot also has distinct monkey characteristics, which would have allowed the girl to hang on to her mother by climbing trees, or by fleeing to a safe place.

"This foot is similar to the human, and this indicates that Dikika's daughter walked on two legs," DeSilva explained to Gizmodo . "However, the bone at the base of our big toe, called medial cuneiform, has a connection to the big toe that is more curved and slightly more angular than what is found in humans today. Such a curved surface would allow the movement of this big toe in the way modern monkeys use it to hold things. Due to this, and to the price studies of the daughter Dikika, we concluded that she could have climbed and caught her mother. "

According to the researchers, the physical characteristics of the daughter Dikika suggest that she was probably a better climber than the adults, and that this girl, like the other babies of A. afarensis has spent more time in the trees than his parents.

"They were smaller, probably more mischievous, and had to flee the trees to get away predators more often than adults, "said DeSilva. "We think it helps to explain the differences we see between the bones of Dikika's little girl and the more human bones of adults."

According to the authors of the study:

Dikika's daughter was of similar size to a chimpanzee of the same age, and it is likely that at that age he was also entirely dependent on adults, and was even constantly charged by them. Taking into account the energy expended during the transportation and transportation of babies, adults and youth may have benefited from the climbing characteristics present at the foot of the water. A. afarensis .

Since A. afarensis developed the ability to walk upright on land, this species, and especially its children, still retained the ability to climb trees. These two types of abilities could have been linked to life in an African ecosystem full of dangerous predators.

Understanding behavior through the study of fossils is precarious practice, so these are just good assumptions. More fossils are needed, but they are often scarce nowadays. Dikika's daughter lived about 3.32 million years ago, and her fossil was compared to Lucy's, which is about 3.2 million years old, as well as fingerprints. Laetoli, which has about 3.6 million. d & # 39; years.

"For your readers, these dates may seem very close, but in reality, Dikika's daughter lived 120,000 years before Lucy, and Lucy lived more than 400,000 years after the draws," said DeSilva. Fossils are rare, and these time scales are so large that we probably do not know much about what happened at that time. But you work with what you have, and you make adjustments as new fossils are discovered. "[Science Advances]