There’s something about dinosaurs that makes them strangely endearing, despite murdering humans in an umpteen number of films, having big teeth, and being related to one of the meanest types of living animal, birds. So lots of people (us, mainly) got excited about evidence showing that Tyrannosaurus rex might look more like an angry, feathered chicken. But a new study is swinging the pendulum in the opposite direction.
An international team of researchers took another look at the skin and concluded that maybe T. rex’s ancestors had feathers, but lost them to evolution. But will we ever really know?
The conclusion comes from a new analysis of HMNS 2006.1743.01 (Wyrex), a T. rex specimen at the Houston Museum of Natural Science in Houston. This partial skeleton has scaly skin on its neck and other parts of its body, which the paleontologists used to deduce that maybe the whole dinosaur might have had a tough scaly exterior rather than feathers. They also looked at other related species—like Albertosaurus, Daspletosaurus, Gorgosaurus and Tarbosaurus—and the specimens were all scaly.
Image: Bell et al, Biol. Let (2017)
However, the researchers don’t rule out that maybe juvenile T. rex had feathers and lost them as they grew, or that all T. rex had feathers on their back. Scientists can ultimately only make conclusions about the specimens that they have.
If the T. rex did lose its feathers, though, that’s another story. Other researchers think feather evolution was a matter of increasing complexity over time, according to the study published today in Biology Letters. Instead, it could have been a more nuanced process, with dinosaurs evolving feathers and losing them through natural selection. Feathers kept dinos warm, but so does growing really big and doing more physical activity. Maybe this would be reason enough to lose the fluff, or maybe the earlier feathers evolved into scales.
So, were T. rex scaly scalawags or feathery friends? Honestly, it’s still hard to conclude. “It takes inconceivable good luck to preserve feathers in fossils. Just because we don’t see them doesn’t mean they weren’t there,” researcher Steve Brusatte of the University of Edinburgh told the BBC. “So I don’t think we need to throw out the image of a big fluffy T. rex quite yet.”
It’s the kind of thing that only more research will be able to really answer. Also, we might never know, because that’s just how palaeontology works. [Biology Letters]