Rare Fossil Reveals “Surprising” Interaction, As It Suggests A Caiman Chomped A Terror Bird’s Leg

The terror bird. It’s a name that strikes fear, and with good reason. These “super predators” from the Phorusrhacidae were a family of massive carnivorous birds that were among the largest predators of their time. A rare fossil has now revealed a surprising weakness, however, as it suggests that 15 million years ago, one died in the jaws of a caiman.

We were very thrilled by the discovery of a bird of terror in Northern South America, after more than 100 years of research in the Miocene site of La Venta.

Andrés Link

Finding direct evidence of trophic interactions like this is pretty rare in the fossil record, which is why it’s so exciting when scientists stumble across a bone with a few bite marks. That was the case for a team examining the distal part of a leg bone from terror bird retrieved from La Venta in Colombia, which revealed four pits that had been inflicted on the cortical bone.

The chomp marks showed no signs of healing, suggesting the bird either didn’t survive the event, or was already dead when it began. A new paper on the finding suggests that the caiman Purussaurus neivensis may have been the culprit, which – whether hunted or scavenged – is pretty impressive on the part of this ancient reptile.

“It was surprising,” said lead author Andrés Link of the Universidad de Los Andes, Bogotá, Colombia, to IFLScience. “At first, we were very thrilled by the discovery of a bird of terror in Northern South America, after more than 100 years of research in the Miocene site of La Venta.”

“As we examined the part of the leg (tibiotarsus) of the terror bird we noticed it had some very intriguing marks that suggested tooth marks. At that moment, I felt this evidence was indeed counter intuitive as it’s difficult to think this super predator – the terror bird – had been predated or scavenged by a large caiman!”

The discovery paints a new picture of how crocodyliforms and large terror birds in the Middle Miocene of La Venta, Colombia, were interacting with one another. It adds to our understanding of what Purussaurus neivensis was capable of eating, and suggests that terror birds might have had a higher predation risk than previously expected. Direct evidence of predation and trophic relationships like this can be invaluable in building a more complete picture of extinct ecosystems, revealing how species interacted in the past. Turns out, waterholes have long been a logistical nightmare for staying alive.

“This article provides evidence on the broad diet of the large caiman Purussaurus neivensis, and the fact that terror birds also could fall prey of other predators, but in my opinion, this study highlights how the terrestrial vertebrates of La Venta must have also used the water holes or water sources where aquatic predators were waiting for an opportunity to hunt,” added Link. “Thus, it resembles how extant herbivores go to water sources to drink or terrestrial predators look for prey and are as well subject to predation by caimans.”

The study is published in the journal Biology Letters.