Scientists have discovered that ancient human babies had special toes that they used to hold on to their mothers and climb trees, though they were also capable of walking on their two feet.
The evidence came from further studies on Selam, a 3.3-million-year-old fossil that was unearthed in the Dikika region of Ethiopia in 2002.
Who Is Selam?
In 2002, paleontologist Zeresenay Alemseged discovered the fossil of a tiny female toddler. The fossil was dated 3.3 million years ago, and was named Selam, meaning "peace" in Ethiopia's Amharic language.
Selam was 3 years old when she died, but over 3 million years after her death, she is giving science further glimpses into the lives of the early human ancestors known as the Australopithecus afarensis. The toddler's nearly complete skeleton was encased in sediment that was also millions of years old, so researchers took years in their careful extraction of the fossil.
One of the more recent components of the fossil that was studied was Selam's foot, and findings on the analysis were published in the Science Advances journal.
Selam's Foot Reveals Special Toe
"For the first time, we have an amazing window into what walking was like for a 2½-year-old, more than 3 million years ago," said lead author and Dartmouth College associate professor of anthropology Jeremy DeSilva in a statement. "This is the most complete foot of an ancient juvenile ever discovered."
Selam's foot, which measures about 2 inches long, features general anatomy that is similar to that of modern humans. However, there is one distinct difference, and that is Selam's big toe.
The ancient toddler's big toe is curved, similar to that of a chimpanzee. However, unlike a chimpanzee's which have their big toes sticking out to the side, her big toe is in line with other toes, like in the modern human's foot.
DeSilva claimed that Selam used her curved toe to grasp her mother's body while she was being carried, and also to climb trees to get food or for protection, especially at night. The last inference was based on the absence of evidence of fire or infrastructure for another million years in Ethiopia after Selam's time, which likely meant that her people survived the night against large predators by climbing up trees.
What Else Has Selam Taught Us?
The special big toe of ancient babies is a significant discovery, but it is far from the only thing that Selam has taught scientists.
Last year, the toddler fossil revealed that the Australopithecus afarensis spine contained 12 pairs of ribs and 12 thoracic vertebrae, which is the same as modern humans.