Image 1 - Large Ancient Crocs Could Have Swallowed Humans Whole
May 8, 2012

Large Ancient Crocs Could Have Swallowed Humans Whole

East African giant crocodiles that lived between two and four million years ago were large enough to swallow an entire human, according to a new study led by University of Iowa researchers.

The fossil of one specimen measured 27 feet long, far larger than any known to date. Scientists first believed it may have been an ancestor of today´s Nile crocodile, but analysis shows otherwise, said lead author Christopher A. Brochu, a vertebrate paleontologist at UoI.

“It´s the largest known true crocodile,” Brochu, associate professor of geoscience, said in a press release. “It may have exceeded 27 feet in length. By comparison, the largest recorded Nile crocodile was less than 21 feet, and most are much smaller.”

While the fossilized specimen resembles that of a Nile crocodile, it has a much different skull and jaw formation than its modern counterpart, noted Brochu. “There´s this misconception that crocodiles are these living fossils that haven´t changed “¦ This is something different, a species of a true crocodile, but different from anything known,” he told the New York Times.

Reporting the findings in the May 3 issue of the Journal of Vertebrate Paleontology, Brochu recognized the new species -- Crocodylus thorbjarnarsoni -- from fossils that he examined three years ago at the National Museum of Kenya in Nairobi. Some were discovered at sites known for important human fossil discoveries, painting a disturbing, yet remarkable picture: that it was possible these large true crocodiles swallowed early humans whole.

“It lived alongside our ancestors, and it probably ate them,” Brochu said. He explained, however, that the fossils collected showed no evidence of human consumption. Despite this, it is known that crocodiles will eat anything they can swallow, and humans during that time period would have stood no more than four feet tall, giving crocodiles of the time an easy meal.

“We don´t actually have fossil human remains with croc bites, but the crocs were bigger than today´s crocodiles, and we were smaller, so there probably wasn´t much biting involved,” Brochu said.

He added that there would likely have been a fair amount of interactions between humans and crocodiles, as early humans would have had to seek out water at rivers and lakes where crocodiles lie and wait.

The new croc find is not a first for Brochu in eastern Africa. In 2010, he published a paper on his finding of a man-eating horned crocodile from Tanzania named Crocodylus anthropophagus. That specimen was related to his latest discovery.

These discoveries suggest that the Nile crocodile, which is taxonomically different from his other finds, is a fairly young species and not an ancient “living fossil,” as some experts have believed.

“We really don´t know where the Nile crocodile came from,” Brochu says, “but it only appears after some of these prehistoric giants died out.”

Although crocodiles in general are ancient, they have evolved considerably over time. Today there are only three to five species of crocodiles in Africa, but in ancient times there may have been double that, he said.

“This would have been a major part of the life our ancestors,” Brochu told New York Times reporter Sindya N. Bhanoo. “If there is something in the water that can swallow you whole, then you´re going to think about how to approach the water.”

His work was funded in part by the National Science Foundation and the UoI Obermann Center for Advanced Studies.

C. thorbjarnarsoni is named after John Thorbjarnarson, famed crocodile expert and Brochu´s colleague who died of malaria while in the field several years ago.

“He was a giant in the field, so it only made sense to name a giant after him,” Brochu added. “I certainly miss him, and I needed to honor him in some way. I couldn´t not do it.”

Image 2 (below): The illustration shows the comparative sizes of ancient/modern crocodiles and ancient/modern humans. Credit: Illustration by Chris Brochu