Uploaded July 2017 | Updated September 2026, 2 hours ago
Presented by Thomas Holtz, PhD at Balticon 51 as part of their Skeptical Thinking track. May 29, 2017.
What if the most bizarre, massive, and improbable animals weren’t from the time of dinosaurs—but from the age after them? In this enthralling lecture, vertebrate paleontologist Dr. Thomas R. Holtz, Jr. takes the audience on a sweeping journey through the Cenozoic Era, the “Age of Mammals,” spotlighting a cavalcade of extraordinary creatures—many of which challenge our everyday assumptions about evolution, extinction, and what counts as "normal" in natural history.
Dr. Holtz’s fast-paced, insight-packed talk draws connections between paleontology, evolutionary biology, science fiction, and scientific skepticism. With wit and deep expertise, he explores how isolated continents, shifting climates, and convergent evolution gave rise to strange and wondrous species—some of them flightless birds that ruled South America, others massive swimming sloths or land-dwelling ancestors of whales.
From ancient oceanic flyers with tooth-like beak projections to ground sloths that tunneled like badgers and carried the bulk of elephants, the Cenozoic biosphere was a world of giants and oddities. And unlike the better-known Mesozoic dinosaurs, many of these creatures lived surprisingly recently—within the last few million years—and interacted with early humans.
Key highlights of the video include the story of Pelagornis, an albatross-like bird with a wingspan more than twice that of modern birds; Argentavis, the largest known flying bird in history; and Terror Birds, the dominant predators of ancient South America. Dr. Holtz also introduces the armored, tail-club-wielding glyptodonts, and reveals how DNA evidence is reshaping our understanding of extinct South American ungulates like Macrauchenia and Toxodon, once enigmas, now known to be relatives of horses and rhinos.
Through vivid reconstructions and recent fossil discoveries, the lecture also touches on the Great American Biotic Interchange—when North and South America connected, sparking a dramatic and deadly migration of species in both directions. Camels, elephants, and big cats moved south; sloths, porcupines, armadillos, and capybaras ventured north. Some even made it to Alaska before vanishing—likely due to the arrival of Paleo-Indians.
Dr. Holtz also explores the extraordinary lineage of whales, beginning with land-dwelling, hoofed ancestors like Indohyus and Pakicetus, progressing through Ambulocetus ("the walking whale"), and culminating in modern cetaceans. The emergence of baleen whales as ocean giants, he explains, is a recent phenomenon tied to oceanographic changes, global cooling, and tectonic shifts like the closure of the Isthmus of Panama.
There are also fascinating tangents into speculative science fiction: Alan Steele’s Coyote novels, which imagine “boids” inspired by terror birds as apex predators on alien worlds. Alongside are nods to creatures that push the boundaries of the plausible—giant rabbits, horned gophers, walrus-like whales, and more—fueling both the scientific imagination and the skeptical mind.
Dr. Thomas R. Holtz, Jr. is a vertebrate paleontologist and Principal Lecturer in the Department of Geology at the University of Maryland, specializing in theropod dinosaurs and science communication. He is widely recognized for his accessible and engaging presentations on paleontology, evolution, and the nature of science, and has been a long-time contributor to public science outreach through organizations like the National Capital Area Skeptics.
Whether you’re a fan of natural history, a teacher of evolution and science literacy, or simply fascinated by animals stranger than fiction, this video offers a compelling look at how Earth's recent past can be as astonishing as its ancient one—and why cultivating scientific skepticism is essential to understanding it.
The views expressed in this presentation are those of the speaker and do not necessarily reflect the views of the National Capital Area Skeptics (NCAS).
#Evolution #Paleontology #Cenozoic #PrehistoricMammals #TerrorBirds #GroundSloths #Macrauchenia #Toxodon #Argentavis #Pelagornis #Ambulocetus #WhaleEvolution #Glyptodonts #WalkingWhales #BaleenWhales #ExtinctAnimals #ScienceEducation #CriticalThinking #ScientificSkepticism #Pseudoscience #ScienceLiteracy #NaturalHistory #ScienceCommunication #Skepticism #VertebratePaleontology #Fossils #AncientEarth #GreatAmericanBioticInterchange #SkepticalThinking #EvolutionaryBiology #CryptozoologyDebunked #SpeculativeBiology #SciFiBiology #WeirdAnimals #NationalCapitalAreaSkeptics #ThomasHoltz #AgeOfMammals #ScienceVsPseudoscience #EducationalLecture #ScientificMethod #ScienceOutreach #SkepticYouTube
Presented by Thomas Holtz, PhD at Balticon 51 as part of their Skeptical Thinking track. May 29, 2017.
What if the most bizarre, massive, and improbable animals weren’t from the time of dinosaurs—but from the age after them? In this enthralling lecture, vertebrate paleontologist Dr. Thomas R. Holtz, Jr. takes the audience on a sweeping journey through the Cenozoic Era, the “Age of Mammals,” spotlighting a cavalcade of extraordinary creatures—many of which challenge our everyday assumptions about evolution, extinction, and what counts as "normal" in natural history.
Dr. Holtz’s fast-paced, insight-packed talk draws connections between paleontology, evolutionary biology, science fiction, and scientific skepticism. With wit and deep expertise, he explores how isolated continents, shifting climates, and convergent evolution gave rise to strange and wondrous species—some of them flightless birds that ruled South America, others massive swimming sloths or land-dwelling ancestors of whales.
From ancient oceanic flyers with tooth-like beak projections to ground sloths that tunneled like badgers and carried the bulk of elephants, the Cenozoic biosphere was a world of giants and oddities. And unlike the better-known Mesozoic dinosaurs, many of these creatures lived surprisingly recently—within the last few million years—and interacted with early humans.
Key highlights of the video include the story of Pelagornis, an albatross-like bird with a wingspan more than twice that of modern birds; Argentavis, the largest known flying bird in history; and Terror Birds, the dominant predators of ancient South America. Dr. Holtz also introduces the armored, tail-club-wielding glyptodonts, and reveals how DNA evidence is reshaping our understanding of extinct South American ungulates like Macrauchenia and Toxodon, once enigmas, now known to be relatives of horses and rhinos.
Through vivid reconstructions and recent fossil discoveries, the lecture also touches on the Great American Biotic Interchange—when North and South America connected, sparking a dramatic and deadly migration of species in both directions. Camels, elephants, and big cats moved south; sloths, porcupines, armadillos, and capybaras ventured north. Some even made it to Alaska before vanishing—likely due to the arrival of Paleo-Indians.
Dr. Holtz also explores the extraordinary lineage of whales, beginning with land-dwelling, hoofed ancestors like Indohyus and Pakicetus, progressing through Ambulocetus ("the walking whale"), and culminating in modern cetaceans. The emergence of baleen whales as ocean giants, he explains, is a recent phenomenon tied to oceanographic changes, global cooling, and tectonic shifts like the closure of the Isthmus of Panama.
There are also fascinating tangents into speculative science fiction: Alan Steele’s Coyote novels, which imagine “boids” inspired by terror birds as apex predators on alien worlds. Alongside are nods to creatures that push the boundaries of the plausible—giant rabbits, horned gophers, walrus-like whales, and more—fueling both the scientific imagination and the skeptical mind.
Dr. Thomas R. Holtz, Jr. is a vertebrate paleontologist and Principal Lecturer in the Department of Geology at the University of Maryland, specializing in theropod dinosaurs and science communication. He is widely recognized for his accessible and engaging presentations on paleontology, evolution, and the nature of science, and has been a long-time contributor to public science outreach through organizations like the National Capital Area Skeptics.
Whether you’re a fan of natural history, a teacher of evolution and science literacy, or simply fascinated by animals stranger than fiction, this video offers a compelling look at how Earth's recent past can be as astonishing as its ancient one—and why cultivating scientific skepticism is essential to understanding it.
The views expressed in this presentation are those of the speaker and do not necessarily reflect the views of the National Capital Area Skeptics (NCAS).
#Evolution #Paleontology #Cenozoic #PrehistoricMammals #TerrorBirds #GroundSloths #Macrauchenia #Toxodon #Argentavis #Pelagornis #Ambulocetus #WhaleEvolution #Glyptodonts #WalkingWhales #BaleenWhales #ExtinctAnimals #ScienceEducation #CriticalThinking #ScientificSkepticism #Pseudoscience #ScienceLiteracy #NaturalHistory #ScienceCommunication #Skepticism #VertebratePaleontology #Fossils #AncientEarth #GreatAmericanBioticInterchange #SkepticalThinking #EvolutionaryBiology #CryptozoologyDebunked #SpeculativeBiology #SciFiBiology #WeirdAnimals #NationalCapitalAreaSkeptics #ThomasHoltz #AgeOfMammals #ScienceVsPseudoscience #EducationalLecture #ScientificMethod #ScienceOutreach #SkepticYouTube
