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Our guest today is Kobayashi Yoshitsugu, a paleontologist and professor at Hokkaido University.
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He’s traveled the world, excavating over 10,000 dinosaur fossils along the way.
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Could be a huge find!
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In 2025, his research group published a groundbreaking paper that stunned the paleontology world.
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They showed that tyrannosaurs grew to enormous size after undertaking an intercontinental migration,
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shedding light on a previously unknown evolutionary process.
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We ask Kobayashi about the meaning of his work, and the joy of being at the forefront of dinosaur research.
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The thrill is in the discovery. What is the fossil trying to tell you?
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In my mind I ask the bones, ‘What were you?’
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Gradually you come to understand how they evolved and their lifestyle.
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The Tyrannosaurus rex measured up to 13 meters in length and nine tons in weight.
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It had a thick skull, and powerful hind legs…
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And an estimated bite force of 3,600 kilograms.
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This apex carnivore is thought to have chewed its prey down to the bone.
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The T-rex thrived in North America until 66 million years ago.
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But where did it come from?
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Faraway in Mongolia, scientists had found dinosaur fossils in a geological layer 90 million years old.
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Something about them spoke to Kobayashi.
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They were thought to belong to Alectrosaurus.
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We analyzed their place in the evolutionary tree – basically, their family history.
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And although they were similar to Alectrosaurus, we found that they were something different.
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The fossils, which had been discovered around 50 years ago, were thought to belong to Alectrosaurus,
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but new analysis revealed they actually belonged to an entirely new species of tyrannosaur.
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A medium-sized one, measuring three to four meters in length and weighing under 500 kilograms.
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Many of its features, including its slim body and skull, resembled a juvenile T-rex.
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The fossils represented a transitional form, showing the evolution in the size of tyrannosaurs.
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Kobayashi’s research group named the species “Khankhuuluu mongoliensis,” meaning “Dragon Prince of Mongolia.”
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Khankhuuluu is a slimmer tyrannosaurus that’s along the evolutionary path to its larger form.
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Here’s the evolutionary tree of so-called tyrannosauroids.
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Khankhuuluu is an intermediate form.
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It marked a transition into larger and larger species, culminating in the T-rex.
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The discovery allowed Kobayashi and his colleagues to unravel the evolutionary history of tyrannosaur varieties over time.
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Large tyrannosaurs originated in Asia, migrated to North America, and diversified.
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A variety of species emerged, and a particularly large tyrannosaurus traveled back to Asia.
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It’s called Tarbosaurus.
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Our theory is that what we know as T-rex evolved from tyrannosaurs that then traveled from Asia, back to North America.
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Today, Kobayashi is a world-renowned paleontologist, but he spent much of his youth lacking direction.
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He enrolled at a Japanese university, but was quickly swept along by those around him and went to study abroad in the US.
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I spoke little English and had no interest in the culture.
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So I treated it like an extended sightseeing trip.
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He returned to Japan after one year, unsure as ever about what path he wanted to take.
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I did what people said I should do.
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But when I peeled away those layers like an onion, there was no core.
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No goal or ambition at the center.
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I thought, this isn’t good.
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I did some self-reflection and happened to come across a book on dinosaurs.
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And I felt a sense of excitement come from within me.
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I thought, “This might be fun. I’ll give it a shot!”
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Kobayashi went back to the US and enrolled at the University of Wyoming, which was known for its paleontology research.
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I was determined to live each and every day without making excuses to myself,
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so that even if I were to die tomorrow, I’d have no regrets.
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So after I enrolled, I went all in on my studies with the attitude of absorbing everything I could.
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In 1995, Kobayashi graduated from his department at the top of his class.
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He then became the first Japanese to earn a PhD in Vertebrate Paleontology from Southern Methodist University.
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He began traveling the world, excavating and studying dinosaur fossils.
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Starting in 2006, he took on the challenge of digging out the full skeleton of a Deinocheirus.
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Back in 1965, a pair of 2.4-meter-long limbs had been unearthed in Mongolia.
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The dinosaur was given the name “Deinocheirus,” meaning “terrible hand.”
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But the rest of its appearance remained a mystery.
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Scientists worldwide have been trying to unravel its identity for over 40 years.
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A bona fide mystery dinosaur.
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An international research group including Kobayashi went looking for the other pieces.
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If this is the skull…
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In 2010, the team finally succeeded in excavating a full Deinocheirus skeleton.
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The creature was around 11 meters long.
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The discovery of a nearly-complete specimen offered a wealth of insights into its life and habits.
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It had a body type totally different from any dinosaur we’d seen before.
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As a paleontologist, it was a once-in-a-lifetime kind of discovery.
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Kobayashi also had success back in Japan.
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– The brown part…
– Ah! A bone!
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All right! We did it!
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In Hokkaido, he helped to excavate Japan’s first nearly-complete dinosaur skeleton
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and published a 2019 paper identifying it as a new species.
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Kobayashi spends four months out of the year in the field, at sites in North America, Mongolia, and more.
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He’s uncovered over 10,000 fossils to date.
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What’s more, he’s been involved in naming over 10 new species.
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What makes him remarkable is his extraordinary knack for locating dinosaur fossils.
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It’s an ability that’s earned him the nickname “Falcon’s Eye.”
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…reason that Yoshi is very well known internationally is because he has such a sharp eye, a falcon’s eye,
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that allows him to find things where other people don’t find them.
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And Yoshi is definitely one of the best people for finding new things.
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I go where others don’t.
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Most people don’t like steep slopes.
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But I walk terrain that others avoid, so naturally I end up making discoveries.
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Colleagues say to me, “We thought we were in new territory, then we saw your footprints!”
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“Walkman” is another of my nicknames.
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I always assume there’s something to be found.
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And the longer I spend not finding anything, the closer I get to a discovery.
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I don’t get disappointed because it makes it more likely the next step will bring success.
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So I never get tired of walking.
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Kobayashi explores perilous, hard-to-access locations.
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That’s why they’re more likely to yield fossils that no one else has been able to reach.
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One time in Alaska, he encountered seven grizzly bears in a single day.
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In Mongolia’s Gobi Desert, a sudden thunderstorm caused a torrent of water a hundred meters wide.
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As thunder approached, Kobayashi found himself stranded.
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I had to cross to get back to camp.
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But then… this huge boulder rolled past, and I knew I was in trouble.
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The water eventually receded, and he barely managed to make it back.
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At the time, I thought I’d never visit again.
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But on the plane home, I thought, “Maybe next year.”
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Fieldwork is my priority. It’s not just about finding fossils.
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I try to think about how dinosaurs lived.
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I get a first-hand experience of the harsh environments in which they existed.
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It’s very stimulating.
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I see fieldwork as the essence of research.
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Long before humans, dinosaurs ruled every continent on the planet, thriving for millions of years.
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Then 66 million years ago, they met their end in an extinction event that radically changed the global climate.
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Their fate is by no means irrelevant to us humans living on Earth today.
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Kobayashi says understanding the dinosaurs is also about contemplating humanity’s future.
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Our planet has endured five extinction events.
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And some scientists say… we’re currently on the verge of a sixth.
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Living things are disappearing from the face of the Earth at an alarming speed.
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And it’s all because of us. Human beings.
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We’re putting a huge burden on our planet.
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Amid all of these mass extinctions, humanity has to figure out how to carve out a future for itself.
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And the past is the perfect teacher.
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The most recent extinction event was that of the dinosaurs.
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But humans are different.
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We have the ability to think and convey ideas.
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Dinosaurs teach us that if we want the human race to survive on this planet as long as possible, we have to be kinder to nature.
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Do you have any words to live by?
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This is a phrase that means “Seize the day.”
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Adults often tell kids to follow their dream, but that can be quite cruel.
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Because you don’t choose your dream, your dream chooses you.
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So how can you encourage that to happen?
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Well, by trying different things, looking deep within, and cherishing the moment.
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Something could spark your interest and lead to a dream. So seize the day.
AloJapan.com