Summary
Highlights
Paleontologist Kenneth Lacovara describes his fascination with finding the largest dinosaurs. He embarks on an expedition to Southern Patagonia, a remote region ideal for finding Cretaceous-era rocks. In 2004, after a month of searching, his team discovers a 2.2-meter-long femur, indicating a massive dinosaur. This discovery leads to a return expedition in 2005 with a larger team, including Matt Lamanna, to further excavate the site.
During the 2005 expedition, a significantly more complete set of bones is found, including an articulated tail, which is crucial for understanding the anatomy of these large creatures. The team excavates a vast area, painstakingly jacketing the bones for transport. Over five years, they recover 70% of the skeleton, far more complete than any other super-giant dinosaur. Using bone circumference, they estimate its weight at 65 short tons, equivalent to 13 African elephants.
Aja Dien, a fossil preparator, describes the meticulous process of extracting and assembling the bones. After three years of lab work, the full skeleton is laid out, revealing an animal 85 feet long and two stories high at the shoulder. Unique features identify it as a new species, named Dreadnoughtus, meaning 'fears nothing.' The team then uses 3D scanning and biomechanical experiments to understand how such a massive animal moved. They discover unusual paddle-like bones in its tail, indicating powerful muscles that could have been used for defense, challenging the perception of docile plant-eaters.
Donald Henderson, a paleontologist, discusses the discovery of a remarkably well-preserved dinosaur. Miners in northern Alberta, Canada, uncover a fossil hit by an excavator bucket. What they find is an armored dinosaur encased in rock. Due to the delicate nature of the fossil and the unstable cliff, specialized excavation techniques are employed by skilled operators to retrieve the specimen.
Mark Mitchell, a fossil preparator, spends five and a half years meticulously removing rock from the fossil. He discovers not just bones, but fossilized skin, making it a rare 'mummified' dinosaur. The reassembled specimen reveals it to be a nodosaur, a plant-eater covered in armor, with distinctive shoulder spikes. The new species is named Borealopelta markmitchelli, after the preparator.
Caleb Brown joins the project to determine the dinosaur's color. Geochemical analysis of minuscule skin samples reveals the presence of pheomelanin, a reddish-brown pigment, providing the first direct evidence of a dinosaur's coloration. The unusual preservation of this land animal in a marine environment is explained by the 'bloat and float' hypothesis. After it died, gases filled the body, causing it to float out to sea before bursting and sinking rapidly, preserving it in protective sediment.
Alan Titus, a district paleontologist, describes his work in a vast fossil-rich area of the American West. Following a flash flood, he, along with Katja Knoll and Mike Knell, discovers a rough-looking bone. Upon further excavation, they realize it's a tyrannosaur bone, a rare and exciting find. The team uncovers 50 bones on the first day, and subsequent excavations reveal an extensive bone bed, indicating multiple tyrannosaurs.
Lab analysis confirms the fossils belong to a new species of tyrannosaur, an older, smaller cousin to T-Rex, dating back 76 million years. By counting repeated bones like left feet, they identify at least five individuals, ranging from a baby to a fully grown adult, found together. This challenges the long-held belief that tyrannosaurs were solitary hunters. Geochemical analysis of rare earth elements in the bones confirms they all died in the same lake at the same time, strengthening the argument for a social, possibly family, group.
The discovery of multiple tyrannosaurs of varying ages dying together suggests that they were social animals, potentially engaging in pack hunting for large prey. This aligns with findings from two other tyrannosaur mass mortality sites in North America, involving different species. The implication is that even T-Rex might have exhibited similar complex social behaviors, elevating the image of these formidable predators from lone killers to intelligent, cooperative hunters.