The discovery of a skeleton called "Lucy" in 1974 sent waves through the scientific community, as she essentially represented a "missing link" between our ape ancestors and modern-day humans. Lucy hails from the species Australopithecus afarensis, natives of Eastern Africa around 3 million years ago.
Lucy walked upright, possessed a face resembling a cross between modern humans and apes, and, like many Australopithecus, displayed other traits familiar to us. Lucy the Hominid told a story through her bones, but she did much more than that. For many people, Lucy started the debate about what it means to be human.
Australopithecus afarensis lived roughly between 2.95 and 3.85 million years ago. In Lucy's case, carbon dating her bones proved impossible; a method called Argon-Argon dating, however, estimated the time frame she lived using the soil content surrounding her remains.
Based on these results, scientists concluded Lucy is "just less than 3.18 million years old."
Researchers agree Lucy died as a young adult. Several pieces of skeletal evidence led to this conclusion, including clues in her teeth. Lucy's wisdom teeth came in and showed signs of wear. Several different points of fusion on her bones also indicate she possessed a fully formed skeleton.
These factors, along with a lack of aging signs, point to her being fully grown but not very old.
Paleoanthropologist Donald Johanson discovered Lucy in 1974. At the time, the Beatles remained wildly popular. After Johanson uncovered the skeleton, he and his team members returned to camp for a celebration. He put on a Beatles cassette and the song "Lucy In The Sky With Diamonds" inspired the skeleton's name.
While scientists still don't know how Lucy died, it appears she didn't suffer an attack by a predator. According to researchers at Arizona State University:
Typically, animals that were killed by predators and then scavenged by other animals (such as hyenas) will show evidence of chewing, crushing, and gnawing on the bones. The ends of long bones are often missing, and their shafts are sometimes broken (which enables the predator to get to the marrow).
Lucy's skeleton didn't show any of these signs, except for one single puncture mark from a carnivore's tooth on her pelvic bone.