Scientists from the University of Iowa have determined that Australopithecus afarensis, one of humanity’s earliest ancestors known for the fossilized 3.2-million-year-old skeleton, Lucy, was hunted and eaten by a giant prehistoric monster that was the ancestor to modern-day crocodiles.
The research team behind the discovery suggests that the ancient crocodile species, named Crocodylus lucivenator, or Lucy’s hunter, could represent one of many other lost species from this era, including other giant prehistoric monsters.
Giant Prehistoric Monster Lived at the Same Time and Place as Lucy
When the Lucy skeleton was unearthed in 1974, it made headlines as a possible “missing link” between early primates and humans. While modern science has dispensed with the concept of a missing link in favor of a more complex human family tree, Lucy’s role as the oldest and most complete human ancestor ever discovered remains significant.
For example, the Lucy skeleton provided further evidence that early human ancestors began walking on two feet before they developed the large brains characteristic of primates in the Homo genus, including humans. The finding has also prompted further research into the environmental challenges this early human ancestor faced, including threats to its very survival that could have doomed humanity before it began.
Corresponding author Christopher Brochu, a professor in the Department of Earth and Environmental Sciences at Iowa, said that the first time he saw the Crocodylus lucivenator specimens during a 2016 visit to an Ethiopian museum, he was “blown away.”
“It had this really weird combination of character states,” the researcher said, explaining his interest in finally identifying the species.
For example, some of the specimens showed that this ancient crocodile had a large hump in the center of its snout. Brochu noted that a similar feature is present in American crocodiles but absent in African Nile crocodiles. The professor said he thinks the ancient Lucy-eating species may have used this feature to attract a mate.
“You see this in some modern crocodiles,” Brochu explained. “The male will lower his head down a little bit to a female to show it off.”
Fossil Analysis Reveals Animal’s Characteristics
To conduct a more in-depth analysis of this potentially new species, Brochu and colleagues examined 121 catalogued remains excavated from the Hadar site in the Afar region of Ethiopia. Unlike Lucy, this collection of fossils represented dozens of different animals.
According to the study authors, this analysis revealed several distinct traits. For example, this giant prehistoric monster ranged between 12 and 15 feet long. Full-sized adults likely weighed between 600 and 1,300 pounds. Although this ancient Lucy hunter was not as large as the largest modern crocodile species, Crocodylus porosus, which can reach up to 20 to 23 feet in length and weigh upwards of 3,300 pounds, it was easily large enough to represent a mortal danger to our much smaller ancient human ancestors.
The analysis also discovered that Lucy Hunter’s snout extended further from its nostrils than those of its contemporaries. Instead, the animal’s snout ratio was more consistent with those of modern crocodiles.
The research team said these features suggest the giant prehistoric monster was likely “a dominant creature and the only crocodile on the landscape.” This included a region-wide expanse of shrubland and wetlands pocked with rivers lined with trees. The Lucy hunter was also likely an “ambush predator” that waited silently while submerged in the water until its prey neared the water’s edge for a drink.
“It was the largest predator in that ecosystem, more so than lions and hyenas, and the biggest threat to our ancestors who lived there during that time,” Brochu explained, adding that it is a ‘near certainty’ the animal would have hunted Lucy’s species.
“Whether a particular crocodile tried to grab Lucy, we’ll never know, but it would have seen Lucy’s kind and thought, ‘Dinner,’” the professor added.
Dominant Creature Was the Only Crocodile on the Landscape
When discussing the implications of their work, the University of Iowa team pointed out that most of the fossils they examined were fragments that required them to “extrapolate the full skeleton. They also noted that the often-incomplete data collected from the fossils only provided the team with a part of a larger picture.
For example, one of the specimens the team examined displayed clear evidence of ‘several’ partially healed injuries to its jaw. The team said the location and partially healed nature of these injuries suggested the animal had tussled with one of its fellow Lucy hunters. Still, according to study co-author Stephanie Drumheller, a teaching associate professor at the University of Tennessee who earned a doctorate at Iowa, similar injuries in the crocodile family tree fossil record provide clear evidence of the suggested ‘face-biting’ behavior.
“We can’t know which combatant came out on top of that fight, but the healing tells us that, winner or loser, this animal survived the encounter,” the professor noted.
Although the Lucy hunter lived alongside several other animals and the region to the immediate south supported several other crocodile species, the team’s research suggests that the giant prehistoric monster had its local territory “to itself.”
“During the Pliocene, Hadar was composed of a variety of habitats alongside its lake and river systems over space and time, including open and closed woodlands, gallery forests, wet grasslands, and shrublands,” explained study co-author Christopher Campisano, an associate professor in the School of Human Evolution and Social Change at Arizona State University. “Interestingly, this crocodile was one of only a few species that was able to persist throughout.”
The study “Lucy’s Peril: A Pliocene Crocodile from the Hadar Formation, Northeastern Ethiopia” was published in the Journal of Systematic Palaeontology.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.