Take a moment to think about the appearance
of a modern bird – like a parrot, or something similar. We know these animals have relatively
thick bodies, feathery coats, unique patterns, and varying colors. Now, let’s look at a
parrot’s skeleton. You’ll notice that based on the bones alone, these birds seem like
they’d have long, slender frames — yet the layers of skin and feather coverings make
them look quite different than their gaunt skeletal structures might suggest. And this exact
phenomenon presents a practical challenge when it comes to reconstructing accurate depictions of
dinosaurs. An increasing number of soft tissue discoveries have suggested that many (though not
all) species of dinosaurs possessed more feathers, layers of fat, and other unusual details than one
might assume based on the outdated depictions many of us grew up with. The challenge of capturing
the forgotten peculiarities of dinosaurs is at the center of “All Yesterdays,” a book written and
illustrated in part by C.M. Koseman — whose work you may recognize from his other most famous book
“All Tomorrows.” The 2012 speculative paleo-art book All Yesterdays was created not just by
Kosemen, however, but also Darren Naish — an expert paleontologist and author, and John Conway:
a skilled paleo-artist. These three are brilliant, and I have links to where you can follow and
support them in this video’s description. Not long ago, I covered a section of this book
titled “All Todays,” in which the authors imagine what might happen if, millions of years into
the future, clueless alien scientists tried to create depictions of long extinct organisms
based solely on the fossil record — with pretty hilarious results. But I can’t emphasize enough
that, despite misconceptions to the contrary, All Yesterdays isn’t trying to belittle the field
of paleontology with these images — or suggest modern scientists are similarly clueless
when it comes to reconstructing dinosaurs. Paleoart has come a long way, thanks in part
to the efforts of these creators. The three authors — all of whom are deeply involved in
the paleontology community themselves — make it clear that modern paleontologists aren’t
just blindly interpreting fossils — but also making great strides in integrating studies of
feather impressions and soft tissue preservation to gain complete pictures of what these incredible
creatures might have looked like. However, there are still, of course, a diversity of
fascinating unknowns when it comes to dinosaurs, and All Yesterdays explores how speculation
— as long as it’s cautiously grounded in science — can both help and even play a vital
role in showcasing the intriguing possibilities of how dinosaurs might have looked and behaved.
All Yesterdays stresses a balance between caution and speculation, always pointing out that
many of the reconstructions within the pages might be completely off the mark. That’s just
the nature of speculation. With that said, let’s get started, and imagine what unique aspects
of dinosaurs may not show up in the fossil record. The first out-of-the-norm reconstruction of
a dinosaur All Yesterdays explores is of a Carnotaurus, drawn at a unique angle by John
Conway. While the bull-horned predators are usually depicted from the side, here, the authors
depict the animal head on — drawing attention to just how strange the animal looks — with its arms
stuck out to the sides in a bizarre display. The idea behind the strange spectacle comes from the
animal’s skeleton, which shows the animal had stunted, ineffectual arms — yet possessed unique
shoulders which would have allowed the animals to spread these arms out sideways in a way utterly
dissimilar to other large predatory dinosaurs, and seemed to serve no practical purpose. So,
the authors imagine the arms on Carnotaurus (and the related Majungasaurus, pictured here in C.M.
Koseman’s one of a kind style) were waved about in mating or territorial displays, potentially
alongside bright colors — not unlike many birds today. A bizarre concept to be sure, but not
altogether improbable given the available paleontological data. Of course, dinosaur colors
might have also gone in the opposite direction. Can you see the Majungasaurs in this image?
How about now? Here, the authors explore the possibility that some dinosaurs might have
had appearances which supported camouflage and mimicry: bending into the natural features of
the environment much like a modern stick-bug. Now, it’s usually smaller animals, not predators like
Majungasaurs, which employ camouflage. But some large modern predators’ body patterns, like the
tiger’s distinctive stripes which allow them to blend into tall grasses, do help them ambush prey.
So, it’s possible certain dinosaurs might have had similar camouflaged appearances. Here’s another
recreation which, at first, might be difficult to see. This is All Yesterday’s speculative concept
for a Plesiosauria, portraying the animal with impressive camouflage. Strange though this might
seem to anyone familiar with traditional portrays of Plesiosauria, the modern oceans are swarming
with remarkable forms of mimicry. Just look at the incredible appearance of something like a leafy
seadragon, and you’ll start to understand just how incredible past ocean life might have looked. Now,
the authors aren’t actually making a scientific assertion that this was what all Plesiosauria
(which for the record, weren’t actually dinosaurs, but adjacent marine reptiles) looked like.
Most Plesiosauria likely had smooth skin for better hydrodynamics, but it’s not impossible
some branches tried an ambush approach which may have favored better camouflage. An interesting
possibility for sure. Back on land, here’s a quite heavily feathered speculative reinvention
of a Therizinosaurus. The Therizinosaurus looks quite menacing based on its skeleton alone,
thanks to the animal’s absurdly long claws, which in the past excited artists and caused them
to make an overly-deadly looking animal — despite the fact the animal wasn’t a predator. The thick
layer of feathers certainly makes the animal look less frightening, and quite different from
their skeletal appearance. If you compare the gaunt skeleton of say, an owl, however, to the
quite different shape of the actual bird, you could start to see how such a difference between
skeleton and body size isn’t too crazy a concept. Therizinosaurus skeletons also have wide hips, so
it’s been theorized they have sizeable physiques. Beyond proto-feathers, All Yesterdays also
explores the hypothetical that some dinosaurs, like Heterodontosaurus, might have had defensive,
quill like structures — not unlike the defense of the modern porcupine. Seem hard to believe?
Well, a recent exceptionally well-preserved specimen of the early ceratopsian Psittacosaurus
was found with bristle-like quills on its tail. The Psittacosaurus is actually one of the most
completely reconstructed dinosaurs, and its appearance is certainly not tame. Paleontologists
don’t think the bristles on its tail were for self-defense, but it’s certainly possible some
geneses like Heterodontosaurus — which we also now know had some kind of spike-like dermal quills
— could have used their bristles for self-defense. Going further into hypothetical territory
regarding proto-feathers, the authors imagine a group of Leaellynasaura Amicagraphica as rotund
furballs quite different from the popular notion of a ‘dinosaur.’ Far from fanciful speculation,
however, the authors’ recreation is based on evidence that the Leaellynasaura lived in a
near-polar region, and almost certainly had to endure sub-zero temperatures. While one might
look at such a reconstruction and think it looks too adorable for a dinosaur, The Authors point
out the hesitancy around depicting dinosaurs as ‘cute’ is a potentially an overly-limiting
one. Also incorporated into this design, Leaellynasaura tails were almost three times as
long as their body, for reasons paleontologists aren’t quite certain of. All Yesterdays depicts
their tails as strange, flagpole-like tools for social displays. While easy to dismiss this
concept as overly-speculative, the authors point out that while it’s certainly unlikely, it’s only
so much weirder than what you might see anywhere else in nature. But appearance is only one half of
the speculative puzzle when it comes to dinosaurs. The authors observe that various unique behaviors
likely weren’t preserved in the fossil record. Just think about the mating dances of birds
of paradise, the unique calls of whales, or even something as simple as the dung rolling
of Dung Beetles. All of these behaviors are huge parts of what gives these animals their identity,
and yet most of them could never be understood from remains alone. And it stands to reason
some dinosaurs might have had behaviors which fall into the same category. Here’s an intriguing
speculative example of the Elasmosaurus, marine reptiles which aren’t actually dinosaurs, behaving
in a highly unusual manner. Here, the authors invent a scenario where the Elasmosaurus lunge
out of the depths and wave their necks — competing to prove who is the strongest. Older art of
Elasmosaurus sometimes shows them holding their necks above the water’s surface with ease, but
modern paleontology has proven these animals had heavy bones and dense necks, which could only be
lifted out of the water with significant effort. So, the authors imagine these animals exerting
such strain as a form of social competition. Of course, this is absolutely and unapologetically
speculative, yet equivalently remarkable behavior is likely lost somewhere in our past. In a similar
vein of speculative thought, here the authors imagine Protoceratops engaging in a behavior
there’s no direct evidence for in the slightest. And yet, certain breeds of goats also climb
trees, a strange-looking behavior you wouldn’t guess the hooved mammals would engage in based on
its body plan alone. It’s something like this sort of unexpected conduct which might be absent in the
fossil record. (and yes, these modern goats? They are not a hoax—they truly hang out in trees.) On
the subject of dinosaurs doing things they’re not known for, playing is certainly a significant
example. Instead of showing a dinosaur striking a pose or getting attacked by a predator, this
recreation shows a Carmarasaurus grandis enjoying a simple roll in the mud. Speculative though this
might seem, almost all living animals engage in some form of play —both larger mammals, but also
various species of birds, reptiles, and even fish take part in behavior for no other practical
reason that it seems to be fun. So dinosaurs, even if they’re sometimes thought of creatures
that lived in constant battle with each other, almost certainly engaged in play too. And here at
the end is an image which, despite its simplicity, is one of the hardest to process. It’s showing a
t-rex just sleeping — but so much of our classic perception of the creature is of a roaring
monster with its jaws agape ready to strike, that we forget the tyrannosaurus is also…
just an animal. And animals sleep — especially hunting animals, who need to conserve energy and
therefore spend a considerable amount of time resting. It’s not certain if T rex’s slept
on their sides or not — but it’s still an intriguing image that gets the viewer to think of
the animal as more than just a machine of death. Ultimately, science and speculation aren’t
concepts in opposition to each other. All paleontological art of long-extinct creatures
is speculative to some degree, and thinking about interesting — albeit unusual — possibilities,
can help us appreciate all we know — and don’t know — about these remarkable animals from the
distant past. And that’s the end of our glimpse at the intriguing “All Yesterdays.” If you liked
this content, please consider supporting Kosemen, Naish, and Conway’s work by purchasing
a copy of the book — and by patronizing their other works and social media, which as
always you can find in the links below. Also, thanks for watching. If you enjoyed this entry,
please lend your support and like, subscribe, and hit the notification icon to stay up to date
on all things Curious. See you in the next video.
