Posted on Categories Discover Magazine
Despite having roamed the planet millions of years ago, thanks to advances in technology, dinosaurs aren’t as inscrutable today as they once were. And over the past decades, in addition to studying what they acted like, including their habits and diets, researchers have specialized in reconstructing and depicting what they looked like — all the way down to specific details like texture and color.
But how do scientists go about pinpointing these details for creatures that died 65 million years ago? It turns out, we actually know more about dinosaur looks than you might think
Of course, there are dinosaurs we know a lot about and dinosaurs we know virtually nothing about — fitting for such a vast, diverse category of animals, and it’s important to resist the urge to lump all dinosaurs together. But some scientists still argue that reconstructing the appearance of certain dinosaurs is an extremely nuanced, detailed process, allowing them to pinpoint their looks with precision.
This 2020 illustration shows the fan-favorite Spinosaurus, the largest-known carnivorous dinosaur. (Credit: Mark Witton)
“We actually know way more than paleontologists tend to convey and also way more than the average person gets,” says Darren Naish, a vertebrate paleontologist specializing in reevaluating dinosaurs. “We’re doing really well, actually, in terms of what we know.”
Read More: Here’s What Dinosaurs Really Looked Like
“I think it’s really anti-scientific, anti-intellectual, and misleading when you get these memes where people say ‘We don’t know what Tyrannosaurus rex looks like, for all we know, it could have been like a giant sparrow’,” adds Naish, who also worked as the paleontology consultant for the Apple TV+ series Prehistoric Planet. “And it’s like, no, it wasn’t like that. We know for sure.”
Experts responsible for reconstructing dinosaurs fall into two main categories: paleontologists, the academics who research prehistoric animals for scientific purposes, and paleoartists, creatives who often have paleontology backgrounds but are more concerned with artistic depictions of the creatures.
These specialists have three core tools at their disposal, the first and most straightforward of which is fossils. This can encompass fossils of bones and bits of skeletons, of course, but also fossilized items from the environment dinosaurs inhabited. The second tool is mummified organic tissue; contrary to popular belief, there are a lot of specimens of mummified bits and pieces of skin from the dinosaur era.
Read More: This Dinosaur Fossil Has Skin Intact – Here’s Why it’s Significant
Thirdly, when fossils and organic tissue material aren’t available, paleontologists and paleoartists rely heavily on anatomical comparisons between dinosaurs and living animals who have descended from them — a phenomenon known as phylogenetic bracketing. For instance, scholars know precisely where T. rex falls on the technique’s branching trees, bracketed by crocodilians on one side and birds on the other.
The fossil record helps paleoartists pinpoint the smallest (and sometimes goriest) details — even this illustration of a T. rex pulling the head off a Triceratops is well-evidenced from fossils. (Credit: Mark Witton)
Of course, this technique can be misunderstood or abused; living animals don’t perfectly represent the ancestors of their respective groups from hundreds of millions of years ago, each with their own evolutionary histories. Still, Naish notes, it’s nonetheless a good tool to have in the toolbox.
When paleontologists and paleoartists work to reconstruct a dinosaur, they usually proceed from the inside out. In other words, they start at the skeleton and then build to details on the surface.
This first step helps scientists determine a dinosaur’s core, basic form by reconstructing its skeleton through fossils like bones, shells and teeth — along with anything else tough enough to survive fossilization.
“Reconstructing a skeleton is a forensic task like the police do, and I think most people would understand that the skeletons you see in museums or photographs are pretty accurate,” says Mike Benton, a vertebrate paleontologist at the University of Bristol.
The Diplodocus, a genus of sauropod dinosaurs, has an instantly-recognizable shape and stance. (Credit: Mark Witton)
From the skeleton, experts can then deduce the posture and stance of the creature, allowing them to cross-reference it with fossils of its footprints. These details then inform things like where and how far apart its feet were placed when walking, for instance.
Then come computer simulations and models. “You can look at the structure of the limb skeleton and then you can model the whole thing in the computer,” says Benton, who adds that experts use these projections to understand where an animal weighed the most, or had the most power.
There are a few bits of preserved muscle tissue for certain extinct dinosaurs, says Mark Witton, a paleontologist and paleoartist at the University of Portsmouth. But perhaps more importantly, scholars can use fossilized bones with scars of where muscles were attached to fill in the gaps.
Plus, since muscle layout is actually quite conservative across the animal kingdom — from humans to, say, crocodiles — experts can look at living animals and get a pretty good idea of what the muscle layout of an extinct vertebrate might be, says Witton. Unfortunately, it’s still unclear how bulky or atrophied these muscles may have been.
“That’s not always clear from fossils, and of course, we know this was very variable among living animals,” says Witton, who also wrote The Paloeartist’s Handbook: Recreating Prehistoric Animals in Art.
It’s similarly tricky to understand whether a dinosaur might might have had fatty tissues deposits. This is something that has virtually no representation in the fossil record, says Witton, although there are exceptions.
Centrosaurus, a genus of herbivores from the Late Cretaceous, sported distinctive, hook-shaped horns. (Credit: Mark Witton)
Skin preserves more often than you might think, but also not as often as we’d like, says Witton. Experts have even made maps of different skin types throughout dinosaur evolution in order to make predictions for species without preserved skin available
Similarly, experts can use depressions, creases and impressions of blood vessels from the surface of bones to help them deduce the type of skin that appeared on top. Skin and bone interact when they’re very close, particularly when the skin is tough or scaly, says Witton.
Still, the sheer size of many dinosaurs makes it difficult to extrapolate from one part of their anatomy to their body as a whole. In other words, knowing what their skin was like on, say, a sauropod’s leg, may not apply to everywhere else on such a gargantuan animal.
In 1996, paleontologists in China discovered some of the first fossilized, feathered dinosaurs. Since then, nearly 50 more well-preserved, feathered dinosaur species have been discovered. These first findings cemented that some dinosaurs were indeed feathered, which allowed experts to learn more about their colors in general.
A Deinonychus, which helped solidify the connection between dinosaurs and birds, pins down a juvenile sauropod. (Credit: Mark Witton)
What’s more, examining these feathered remains under the microscope reveals they’re clad in well-preserved microscopic organisms. At first, they were mistakenly described as bacteria. But in the early 2000s, scholars proposed an alternative explanation, revealing that the elongated, sausage-like molecules were actually melanosomes — cells containing melanin that give color to hair in mammal and feathers in bird. In 2010, Benton’s lab published a study describing how to ascribe color to different dinosaurs by looking at the shapes of different melanosomes.
“The fact it’s the same relationship with color and shape in both birds and mammals gave us the confidence that we could apply it to almost any fossil group,” says Benton, adding that these pigment cells have different arrangements, densities and orientations, providing information about a dinosaur’s patterns, stripes and color arrangements.
The last step may be the trickiest: Possibly the most controversial part of reconstructing a dinosaur’s appearance is determining what, exactly, their faces looked like. Some researchers say that the detailed, external bone surface texture on the face of, say, the T. rex is just like that of a crocodilian. Meanwhile, other scientists looking at the same data believe it’s consistent with animals that have extensive soft tissues on the face and a lot of skin built up around the jaw edges.
Tyrannosaurus rex bellowing with its mouth shut, like a vocalising alligator. With its mouth closed, all of the enormous teeth of T. rex would be invisible behind its lips. (Credit: Mark Witton)
“Within a few years, if we do the right studies, we should be able to come up with standardized reconstructions for things like the face of T. rex or the face of something like triceratops, we’ve already done this for some horned dinosaurs,” says Witton, whose lab published the 2023 paper in Science detailing that Tyrannosauruses actually probably had lips that concealed their teeth — upending the way they’re often depicted in the media.
Dinosaur faces aren’t the only area of contention. When it comes to their appearance overall, some scientists suggest we should only depict what we know for sure, while others think experts should engage in some educated guesswork to explore the visual possibilities of their existence.
“There’s lots of extreme weirdness going on in living animals, and that sort of stuff was surely present in the animals of the past,” says Naish, who also co-wrote All Yesterdays, a book that speculates what different dinosaurs might have looked like. “They played by the same rules as living animals do today, in terms of their lives being governed by the need to court and mate and all that sort of stuff.”
The Giraffatitan, one of the largest animals to have ever lived, lived on a Jurassic floodplain next to the ancient Tanzanian coastline. (Credit: Mark Witton)
Regardless, not a lot of the mainstream media depictions of dinosaurs do a great job at accuracy. (We’re looking at you, Jurassic Park franchise.) Many follow the “rule of cool”, says Naish, featuring creatures with gnarly mouthfuls of teeth and razor-sharp claws.
“I wonder [about] this continued monstrification of prehistoric animals to make them look scary [or] awesome,” says Naish. “Is this actually kind of a bad thing for the societal understanding of not just prehistoric animals, but how people imagine the past?”
Their depiction on the silver screen aside, paleontologists and paleoartists are continuing to unravel more nuances about what these prehistoric beasts looked like some 65 million years ago.
Read More: Tyrannosaurus Teeth Were Hidden Behind Lizard-Like Lips