"I've got a dinosaur!" When palaeontologistA scientist who studies fossils to learn about history. Chris Griffin dug up an enormous thigh bone in Zimbabwe, he immediately realised what it was. "I knew I was holding Africa's oldest dinosaur." Over the next few weeks, his team unearthed a near-complete skeleton.

Mbiresaurus raathi¹ was a dog-sized plant-eater living in the late TriassicA geologic period spanning from 252 to 201 million years ago.  on a supercontinent called PangeaAlso known as Pangaea, the supercontinent that existed before the Earth's land separated out into different continents. . The descendants of this small dinosaur evolved into the sauropodsSauropods are known for their long necks, tails, four-legged stance and plant diet. ² - the largest creatures ever to walk on Earth.

Around 252 million years ago, a devastating event³ wiped out 90% of all life. However, the catastrophe was an opportunity for the "terrible lizards". They conquered land, sea and air until 187 million years later, when a massive asteroid⁴ ended the age of the dinosaurs.

Mbiresaurus raathi "shows that dinosaurs didn't start out worldwide, ruling the world from the very beginning," says Griffin. Early dinosaurs lived in humid southern regions. They only ventured north when the world became wetter and more hospitable. 

This is "one of the most important dinosaur discoveries anywhere in the world," says palaeontologist Stephen Brusatte. But what do the lives of ancient monsters have to do with us?

Very little, some argue. Around 60,000 years ago, humans began to make fine stone tools, deadly weapons and the first musical instruments⁵. This started a mental, cultural and technological revolution that catapulted humanity from caves into cities and to the moon.

"The dinosaurs became extinct because they didn't have a space program," wrote science fiction writer Larry Niven. Unlike them, we have language, science and technology to solve our problems. For critics, digging up bones will not stop war, disease or climate change.

Not true, argues palaeontologist Mary Schweitzer. "The fossil record," she says, "tells us that climate change is the planet's 'normal' state." If scientists had not discovered evidence of five previous mass extinctionsScientists studying the fossil record have documented five major mass extinctions in the last 450 million years. , we wouldn't be able to ask if humans are "causing a sixth global die-off".

"The best way to look ahead is to look behind," says Schweitzer. For millions of years, dinosaurs were incredibly successful. They had "a huge set of evolutionary advantages," says palaeontologist Darren Naish, from "batteries" of teeth⁶ to feathers and powerful vision.

They are also not extinct. Some survived the apocalyptic asteroid strike 65 million years ago. Humans share a planet with at least 10,000 species of living dinosaurs in many sizes, shapes and colours. They are modern birds.

In the mid-1990s, a farmer in rural China stumbled upon the world's first known feathered dinosaur, Sinosauropteryx⁷. Since then, further research has put the question beyond doubt. Birds are dinosaurs.

"Learning the secret of flight from a bird," wrote Orville Wright, "was a good deal like learning the secret of magic from a magician." He and his brother Wilbur invented the aeroplane⁸ in 1903. So perhaps, after all, we have dinosaurs to thank for air flight and space travel?

Yes: Over 99% of all species that have ever lived are now extinct. So if we want to understand the full range of ways to survive and flourish on Earth, we must look back into our distant past.

No: Fossil hunting may be fun, and dinosaur films are entertaining. But we cannot justify spending public money digging up the past when we must worry about human problems and building the future.

Or... Science is all about exploring the unknown. When we look deep into our past, we cannot know what we will find or whether it will help future generations. But if we do not look, we will never know.