From: cleoabram
The current era is considered a “Golden Age” of dinosaur discovery, with scientists uncovering almost one new dinosaur species per week on average [00:00:44], [00:01:12]. These frequent discoveries are challenging long-held beliefs about these ancient animals [00:01:18].
The Process of Excavating and Analyzing Dinosaur Fossils
Scientists are currently discovering more dinosaurs than at any other time in history [00:01:07]. An active dinosaur dig site in Alberta, Canada, known as the “Pachyrhinosaurus omelet,” contains hundreds, potentially thousands, of Pachyrhinosaurus bones jumbled together [00:01:33], [00:02:04], [00:02:12]. This site is one of the densest dinosaur bone beds in North America, estimated to contain between 6,000 and 10,000 animals [00:02:48].
Dr. Emily Bamforth, a paleontologist, explains that assembling a dinosaur skeleton is like doing a jigsaw puzzle where you don’t know the picture, are missing half the pieces, have pieces from other puzzles, and some pieces are ripped or torn [00:02:18], [00:02:27].
To hunt for dinosaurs, two rules are crucial: always work horizontally to the bone layer to avoid damaging bones, and always keep the site clean [00:08:16], [00:08:24]. Once found, bones are covered in a paste that dries to protect them for transport to the lab [00:11:36], [00:11:40]. In the lab, bones are cleaned, revealing their shiny chocolate-brown fossilized surface [00:16:38], [00:16:55].
The Nature of Fossils
All dinosaur “bones” are fossilized, meaning they are now made of rock [00:17:03], [00:17:05]. The original bone material is replaced by minerals over millions of years, creating an exact stone copy of the bone [00:17:13], [00:17:18], [00:17:23].
Challenges in Paleontology
Almost half of all dinosaur species are known from only a single, often incomplete, specimen [00:08:49], [00:08:55]. This makes it difficult to distinguish new species from variations of existing ones [00:09:01], [00:09:06]. Paleontologists believe we are “nowhere near having all the dinosaurs that ever lived” [00:09:11].
Misconceptions about Dinosaur Appearances and Behaviors
Dinosaur Size
Dinosaur sizes varied immensely [00:04:14]. The Anchiornis was slightly larger than a basketball [00:04:22]. The Compsognathus was the size of a small chicken [00:04:27]. Velociraptors, contrary to popular depictions, were about the size of a German Shepherd [00:04:30], [00:04:37]. The Nyasasaurus was also about the size of a German Shepherd [00:05:10]. The Pachyrhinosaurus was considered medium-sized [00:04:14]. Triceratops were about the height of an Asian elephant but much longer [00:05:16]. The Stegosaurus and T-Rex were larger still [00:05:22]. Some of the largest known dinosaurs, like the Argentinosaurus, were as long and heavy as a commercial airplane [00:05:30], [00:05:36].
Physical Appearance
- Feathers: Newer research indicates that Velociraptors had feathers [00:04:42]. A 1998 discovery in China significantly changed the understanding of some dinosaur appearances, and subsequent discoveries have confirmed that more dinosaurs had feathers than previously thought [00:04:52], [00:04:57].
- Color and Skin: While there is ongoing debate about the exact color and external appearance of dinosaurs [00:05:01], fossilized feathers sometimes preserve pigment, indicating some feathered dinosaurs were black and white with shiny feathers, or had rust/deep red colors [00:15:10], [00:15:20]. Dinosaur skin, which feels like rock, does not preserve color but can show shading, suggesting some dinosaurs had stripes [00:14:35], [00:15:25], [00:15:31].
- Posture and Body Mass: Early depictions of the T-Rex showed it as a lean predator standing upright like a kangaroo, with its tail dragging [00:09:26], [00:09:30], [00:09:35]. However, comparisons of hip and thigh bones to modern upright animals and new computer models revealed that standing upright would put too much weight on its hips [00:09:40], [00:09:46]. Leaning forward was much more stable, making them “more like teeter totters” [00:09:50], [00:09:57].
- “Shrink-Wrapping”: Many early scientific illustrations “shrink-wrapped” skin around skeletons, ignoring muscle and fat, which is now known to be inaccurate [00:15:55], [00:15:59], [00:16:18]. Most dinosaurs were much chunkier than commonly depicted, requiring significant muscle mass to move [00:10:21], [00:16:22]. Modern artists and scientists are correcting this by adding more loose skin, muscles, and fatty tissues [00:16:28].
Dinosaur Lifespan and Coexistence
A common misconception is that all dinosaurs lived at the same time [00:05:51]. Dinosaurs ruled the Earth for 180 million years [00:06:13]. Some dinosaurs thought to be contemporaries were actually separated by millions of years [00:06:21], [00:06:25]. For instance, more time separates the Stegosaurus from the T-Rex than separates the T-Rex from humans [00:06:32].
Defining “Dinosaur” and The Connection between Birds and Dinosaurs
Scientifically, a dinosaur is defined phylogenetically, encompassing all descendants from a specific branch of ancient lizard-like creatures called amniotes [00:11:50], [00:12:02], [00:12:17]. This means that some animals often called dinosaurs are not, such as Pterosaurs, Mosasaurs, Plesiosaurs, and Ichthyosaurs, which belong to different groups of reptiles [00:12:24], [00:12:29], [00:12:34]. Crocodiles, though alive at the same time, also branched off earlier and are not dinosaurs [00:12:38].
Crucially, under this scientific definition, birds are dinosaurs [00:12:51], [00:12:57]. This means that dinosaurs are still alive today, and they are “all around you” [00:13:03].
Insights from Dinosaur Fossils
Fossilized remains offer incredible insights into dinosaur lives:
- A Tyrannosaur tooth shows serrated edges for cutting flesh [00:13:35], [00:13:40].
- Healed breaks on bones indicate injuries sustained during their lives [00:13:43], [00:13:47].
- Abnormal bone growths suggest dinosaurs could suffer from conditions like osteoarthritis or bone cancer [00:14:13], [00:14:18].
- Actual preserved dinosaur skin can be touched, revealing different kinds of scales [00:14:31], [00:14:35], [00:14:45].
The Extinction of Dinosaurs and Its Impact on Earth’s History
The non-avian dinosaurs, which had reigned for 180 million years [00:18:54], faced a catastrophic event 66.04 million years ago [00:17:35]. A massive rock, wider than Mount Everest is tall and traveling at 20 to 30 kilometers per second, struck Earth [00:17:48]. The impact instantly vaporized the space rock and catapulted Earth chunks beyond the atmosphere [00:17:56], [00:18:02].
On the surface, the impact created an apocalypse [00:18:08].
- A “thermal pulse” of heat swept across the planet [00:18:13].
- Mega tsunamis rippled across the globe [00:18:17].
- Ejecta from the impact blocked out the sun, plunging the entire planet into darkness [00:18:29].
- With less light, plants died, leading to the collapse of the food chain [00:18:34].
The creatures that survived were typically small, German Shepherd-sized or smaller, and had refugia like water or underground shelters [00:18:37], [00:18:44]. This extinction event, though a “bad day on planet Earth for the dinosaurs,” was a “really great day for mammals,” as it allowed them to flourish, ultimately leading to the rise of humans [00:19:02], [00:19:09].
The Future of Paleontology
The study of dinosaurs helps us understand Earth’s geologic history, revealing where life has been, where it is, and where it is going [00:19:40], [00:19:44], [00:19:50]. This “Golden Age of paleontology” continues, with many mysteries yet to be unlocked through ongoing scientific and technological advancements [00:19:55], [00:20:00].