Lex Fridman Podcast Episode #480 with Dave Hone T-Rex, Dinosaurs, Extinction, Evolution, and Jurassic Park

Podcast Date: September 4, 2025 Guest: Dr. Dave Hone (Paleontologist, podcast host, author) Host: Lex Fridman

Episode Overview

Lex Fridman interviews Dr. Dave Hone, a leading paleontologist specializing in dinosaur ecology and evolution, and co-host of the Terrible Lizards podcast. The conversation explores the anatomy, behavior, and evolution of Tyrannosaurus rex, with deep dives into extinction events, paleontological methods, and cultural representations like Jurassic Park. Hone gives rich, fascinating insights into what science has learned—and still wonders—about the time of the dinosaurs, highlighting both the detective-work and the limitations inherent to paleontology.

Main Topics & Key Insights

Standing Before T. Rex: Scale, Anatomy, and Perception
[07:39–19:38]

• Dave paints a vivid picture of the T. rex’s sheer size and physical features:
  • Length: ~12 meters, height to head ~4.5–5 meters, weight 7+ metric tons.
  • Compared to modern animals: "A colleague of mine, Tom Holtz, described them as an orca. On land. That's it. It is a killer whale sized animal but on legs, on land." (B, 08:18)
  • Robust, boxy skull with forward-facing, "tennis ball-sized eyes," massive bite force, and famously proportionally tiny arms.
• Museums and zoos rarely provide true scale: "Even when you get up relatively close to a T. Rex skeleton... you don't actually get to stand, like, under them." (B, 09:33)
• T. rex arms: essentially vestigial, two fingers, not very functional for predation or manipulation.
• Feet adapted for stability and efficiency: Specialized energy-return adaptations in the metatarsals allow efficient movement for such a large biped.
• Bipedalism and movement: Most likely a fast "power walker"—not running in the technical sense—with stride length accounting for speed.

Memorable quote:
"It's a killer whale sized animal but on legs, on land... You realize that. Yeah, the foot finishes at my knee." (B, 08:18–10:19)

T. rex Biomechanics and Hunting
[19:38–43:17]

• Locomotion powered by the tail’s giant muscles—a system present in crocs, lost in mammals.
• Top speed upper bound estimate: ~25 mph (40 kph), more likely a bit lower.
• “It's not going to run in the conventional biomechanical sense where both feet are off the ground at one point... When you've got a four or five metre long stride, it doesn't really matter.” (B, 23:24)
• Question of predation strategy: Not likely tackling adult giants like Triceratops; instead, targeting juveniles of other large species.
• Classic predator-prey dynamics: Predators nearly universally target much smaller, less experienced, and poorly armored juveniles.

Notable exchange:
A: "What would be the survival strategy?” — B: “We may not even be considered on the menu... We might actually be okay." (25:21–26:39)

T. rex’s Vision and Senses
[27:39–29:33]

• Debunks "Jurassic Park" claim that T. rex couldn't see stationary prey.
• T. rex possessed excellent eyesight: "Tennis ball-sized" eyes with visual acuity potentially exceeding that of modern eagles.
• Likely nocturnal or crepuscular, with large eyes adapted for low-light hunting.

Predation, Scavenging, and Cannibalism
[43:17–44:07; 163:34–167:21]

• T. rex did both scavenging and active predation, with direct evidence from bite marks and healed wounds.
• Hunting style compared to wolves or hyenas—efficient, long-range searchers rather than short-burst speed specialists.
• Cannibalism evidenced by T. rex bones with T. rex bite marks; eating conspecifics was rare but occurred, usually in desperate scenarios or as opportunistic scavenging.

Fossil Discovery, Excavation, and Interpretation
[46:26–62:10]

• Basic method: "You go there and then you walk around and you look. And that's basically it." (B, 46:35)
• Most discoveries are bits visible on the surface; full skeletons are extremely rare.
• Process for major specimens (e.g., Stan the T. rex): Remove overburden, carefully map and extract, use glue to stabilize, wrap in plaster jackets for lab prep.
• Plotting and diagramming at the site is crucial for interpreting post-mortem movement, taphonomy, and fossilization context.
• Preparation can take decades and tens of thousands of lab hours.

Dinosaur Diversity, Evolution, and Behavior
[44:10–45:40; 80:24–113:32]

• 1,500–1,600 valid species named; 40–50 new each year. Many new sites and regions remain underexplored.
• Evolution: Tyrannosaurs had small, feathered ancestors; gradual increase in size and bite force over millions of years.
• Evolutionary pressures favoring size: dominance, energy efficiency, competitive advantage, but with increased vulnerability during extinction events.
• Evidence for sociality, display features, and even possible pack hunting in some species—but extremely difficult to prove.
• Intelligence: T. rex intelligence likely comparable to modern crocodilians—smart, possibly clever in some ways, but not primate-level.

Quote:
"A friend of mine, Tom Holtz, described them as an orca on land." (B, 08:18)

Science, Museum, and the Paleontology "Wish List"
[69:26–74:24]

• If granted billions: "I'd probably drop half a billion or so on the best museum you'd ever seen..."
• Emphasizes need for funding not just displays, but land acquisition, basic research, and global collaboration.
• Fossils are a finite, disappearing resource: “If we don't dig them up, they're gone. So we should dig all the fossils up now and then we've got forever to study them..." (B, 72:59)

Jurassic Park: What Hollywood Gets Right and Wrong
[97:03–152:24]

• Accuracy: "Can't see if you don't move" is pure fiction.
• Velociraptors depicted much larger, pack-hunting, and featherless—contradicts evidence for actual animals.
• Films get T. rex general proportions correct; some pterosaurs accurately depicted (esp. JP3), but later films regress.
• Critiques lack of commitment to detail and authenticity; accuracy is feasible and could enhance storytelling impact.
• Positives: Spielberg's team gave back to the science community via the Jurassic Foundation to fund dinosaur research.

Quotable Take:
"Accuracy isn't any harder to do than inaccuracy... If that's truly the case, then just make it right and then you can claim a level of accuracy and engagement.” (B, 146:11)

Social and Sexual Behavior, Feathers, and Modern Birds
[115:05–129:07; 202:39–209:05]

• Mutual sexual selection and display features inferred from bony crests and ornamentation.
• Difficulty of determining sex in dinosaur fossils; medullary bone in egg-laying females is a rare diagnostic.
• Feathers evolved first for insulation, then for display; birds are literally dinosaurs by evolutionary descent.

Extinction: Causes and Consequences
[169:05–179:58]

• Dinosaurs (except birds) wiped out by a massive asteroid strike 66 million years ago, causing near-instantaneous "nuclear winter" and climate collapse.
• Large animals more vulnerable due to required resources and slow reproduction; birds and mammals survived as smaller, adaptable lineages.
• Some dinosaurs likely persisted locally post-impact, but not enough to repopulate Earth or compete with rising mammals and birds.
• If not for the asteroid, mammals/primates/humans likely would not have evolved as they did; Earth would have remained a "dinosaur planet."

Quote:
"The worst possible combination. They were mostly big and they were mostly on land and yeah, it's not really surprising. They did very badly out of it." (B, 172:53)

The Detective Work of Paleontology
[134:50–137:24; 167:05–169:05]

• Much of paleontology is reconstructing lost behaviors and ecologies from scant signals: bite marks, stomach contents, taphonomic clues, rare trackways.
• A single extraordinary specimen can revolutionize thinking, but data is always limited and probabilistic.
• Emphasizes the field is constantly improving with new discoveries, technologies, and comparative approaches.

Beauty, Evolution, and the Wonder of Life
[209:05–220:47]

• Studying hundreds of millions of years of life, Dave feels both awe and humility at the sheer scale and diversity seen in Earth's evolutionary history.
• Dinosaurs dominate by size, diversity, and planetary tenure, but evolution is a massive, numbers-driven process with abundant surprises and astonishing adaptations.
• Birds, as living dinosaurs, are a fascinating evolutionary triumph of the same lineage that once ruled the planet.

Quote:
"It's rolling dice but it gets to keep the sixes. And then suddenly getting a hatful of sixes isn't that hard..." (B, 192:04)

Notable Quotes & Timestamps

• “A colleague of mine, Tom Holtz, described them as an orca on land. That's it. ...Killer whale-sized animal on legs.” (B, 08:18)
• “T. rex has giant eyeballs... When you think about the incredible visual acuity of something like an eagle, which has eyes not much bigger than ours, think about what that's going to do.” (B, 28:01)
• “The evidence for pack hunting in any dinosaur at all is almost non existent. It basically doesn't exist.” (B, 100:43)
• “If we don't dig [fossils] up, they're gone. So we should dig all the fossils up now and then we've got forever to study them...” (B, 72:59)
• “Birds are dinosaurs. The direct — if you trace back the evolution of all the birds...the nearest relative to them is a dromaeosaurid dinosaur.” (B, 203:28)
• “Dinosaurs are animals in ecosystems. They're not that strange at some level.” (B, 185:16)
• “They were mostly big and they were mostly on land and yeah, it's not really surprising. They did very badly out of it.” (B, 172:53)
• “Extinction is the rule. Survival is the exception.” — Carl Sagan (Lex’s closing, ~222:00)

Timestamps for Important Segments

• [07:39] — T. rex anatomy and scale
• [13:06] — Bite force and jaw function
• [16:24] — Foot adaptations and energy efficiency
• [19:22] — Bipedalism and tail muscle function
• [22:17] — T. rex speed and locomotion
• [24:52] — Human survival in T. rex habitat
• [29:33] — Nocturnality and vision
• [35:21] — Stomach contents, predation on juveniles
• [43:17] — Scavenging versus hunting; evidence for both
• [46:26] — How paleontologists find fossils
• [52:03] — Excavation and preparation of fossils (case study: Stan)
• [62:10] — Museum prep, restoration, and public display
• [80:24] — Skull evolution, bite force
• [97:03] — Jurassic Park: fact, fiction, and representation
• [113:32] — Sociality and pack hunting: evidence and controversy
• [169:05] — The end of the dinosaurs: asteroid extinction
• [202:39] — Are birds dinosaurs?
• [209:05] — Reflection on beauty and meaning in evolutionary history

Closing Thoughts

Through vivid analogies, deep scientific reasoning, and humor, Dave Hone brings to life the (sometimes literal) bones of an ancient, vanished world. Tyrannosaurus rex emerges as both a monstrous superpredator and an animal not so different from those living today: subject to the same ecological rules, evolutionary pressures, and even quirks of biology and potential for beauty. Paleontology, as Hone reveals, is as much a detective story as a branch of natural science—and our understanding is always growing.

Lex sums it up perfectly, quoting Carl Sagan:
"Extinction is the rule. Survival is the exception." (Lex, 222:00)

For further detail and illustrations, see Dave Hone’s forthcoming book, Spinosaur Tales, and his regular science communication on the Terrible Lizards podcast.