In a primeval version of the horror flick Lake Placid, a 19-foot-long (5.8-meter-long) horned crocodile may have leaped from the water to snack on early humans, a new fossil find suggests.
The newly described, 1.84-million-year-old species has been dubbed Crocodylus anthropophagus, which means "eater of humans" in Latin.
The croc's fossils were discovered in 2007 in Tanzania's fossil-rich Olduvai Gorge, a site that was also home to early humans—or hominids—such as the tiny species Homo habilis and Australopithecus boisei.
Crocodile bite marks had previously been found on hominid bones from the gorge. Based on the latest find, scientists suspect that the crocodile not only ate our ancestors, but that it was their biggest predator at the time.
The research adds another dimension to understanding how early humans lived in ancient Africa, said study leader Christopher Brochu, a paleontologist at the University of Iowa.
"When people think about [the animals that lived with] early humans, they think about lions and gazelles—the mammals. They don't usually think about the reptiles," he said.
"But our ancestors had to deal with big crocodiles—that's a major part of the landscape."
New Croc Created Dangerous Territory
The new crocodile's fearsome triangular horns are not that unusual, Brochu said. Modern Cuban and Siamese crocodile species also have the bony protrusions above their ears. (See crocodile and alligator pictures.)
The horns serve to exaggerate male crocodiles' perceived sizes during territorial displays, according to Kent Vliet, an expert in crocodile behavior at the University of Florida in Gainesville who was not involved in the new study.
During their displays, horned crocodiles tip their heads forward in the water. "The ultimate effect [is] that the head and the horns and neck form a pyramidal shape, with the horns being the pinnacle," Vliet said.
As with some species of deer, the bigger the croc, the bigger the horns—making the heftiest males the most intimidating.
It's likely that the new predator's horns served the same territorial purpose, Vliet added. (See pictures of five ancient "oddball" crocs.)
The newfound species also probably looked and acted much like the modern-day Nile crocodile, which ambushes anything unwary enough to approach the water's edge.
That means early humans would have had to tread carefully while collecting water from lakes and rivers, as many Africans do today, said study author Brochu, whose research appears this week in the journal PLoS ONE.
But even though people should remain wary of crocodiles, the tables have turned in modern times, Brochu pointed out.
Whether we're killing them outright or destroying their habitats, he said, "the biggest threat to crocodiles today is humans."