Tyrannosaurus Coprolite: A Feathered Turd

Publication Info:

Transcript:

Jingmai K. O’Connor, et al, Bird feathers from a Late Cretaceous coprolite, Current Biology (2026). DOI: 10.1016/j.cub.2026.08.054

This coprolite from the hell creek formation could be from Tyrannosaurus rex or nanotyrannus, and its unlocking the secrets of the hell creek food chain. Scales, feathers, and bones are all sealed away in this small rock!

Episode 341

Notes:

Let's uh talk about T. rex turds, specifically this one. So, fossilized dung is called a coprolite. It doesn't matter if it's a dinosaur, it's a mammal, whatever. Coprolites are a type of ichnofossil, basically a trace fossil. Unlike most ichnofossils, a coprolite can't generally be narrowed down to an exact species or sometimes even a rough group. For example, this is a piece of probably a plesiosaur coprolite. It is at least a marine reptile. But, just like the trackways we talked about yesterday, if you're working in an ecosystem that only has one giant predator you find a giant Hershey squirt full of animal bones, you can kind of make some assumptions. Now, to be fair, this new find is not giant. But, in this case, it's not really the size that matters because paleontologists are confident that this belongs to either a medium or large latest Cretaceous predator from the Hell Creek Formation, which means most likely T-Rex or Nanotyrannus. And, you've probably already noticed what's so special about this coprolite. And, yes, that's a feather. And, this coprolite was collected based on that feather because one feather from the Hell Creek Formation is incredible. But, that wasn't all that was there because CT scanning revealed multiple feathers and gar scales and partial leg bones from a hesperornithiform bird, all in a rock that you could hold in the palm of your hand. Meaning that this one little rock is helping unlock the food chain of the Hell Creek Formation. A hesperornithine relative ate a gar and then turned around only to be eaten by a T. rex or Nanotyrannus. And, it's all preserved right there. And, on top of that, this is the first hesperornithiform feather ever recovered. And, it's giving paleontologists new insights into why the hesperornithiform birds didn't survive the end-Cretaceous mass extinction while the birds we have today did because anatomically they seem pretty similar. But, their feathers may not have been. Hesperornithines may have had much more primitive downy feathers than our modern birds. And, that could be part of why these animals did not survive the end-Cretaceous mass extinction. Their downy feathers just couldn't insulate [clears throat] them from the rapid changes in the climate around them. As usual, if you want more information, here's the source.