Skip to Content
MIT News: 77 Mass Ave

Social life in the Jurassic

Fossils indicate that dinosaurs may have lived in cooperative herds as early as 193 million years ago.

February 23, 2022
dinosaur bones
Using x-ray tomography, scientists scanned fossilized dinosaur eggs to discover preserved embryo skeletons, which they used to confirm nearby fossils as Mussaurus patagonicus.VINCENT FERNANDEZ

To borrow a line from Jurassic Park: Dinosaurs do move in herds. And a new study by researchers from MIT, Argentina, and South Africa shows that they lived that way 40 million years earlier than previously thought.

Since 2013, members of the team have excavated more than 100 dinosaur eggs and the partial skeletons of 80 juvenile and adult dinosaurs from a fossil bed in Patagonia. Using x-ray tomography, they were able to examine the eggs’ contents without breaking them apart. The embryos confirmed that the fossils were all Mussaurus patagonicus—a plant-eating dinosaur of the early Jurassic period that is considered a sauropodomorph, a predecessor of the massive, long-necked sauropods.

To date the dinosaurs, Jahandar Ramezani’s lab at MIT analyzed zircons—mineral grains containing uranium and lead—in volcanic ash deposited in the sedimentary layers where the fossils were found. From uranium’s half-life, or the time it takes for half of the element to decay into lead, he calculated that the ash—and thus the fossils—was around 193 million years old. 

Surprisingly, the fossils of eggs and hatchlings were found in one area, juveniles in another, and adults throughout the site. This “age segregation” may indicate a complex social structure. The dinosaurs likely worked as a community, laying their eggs in a common nesting ground. Juveniles would have congregated in “schools,” while adults roamed and foraged for the herd.

Sauropodomorphs originated in the late Triassic, shortly before many other animals went extinct, and held on to dominate the early Jurassic. This finding “raises the question now of whether living in a herd may have had a major role in dinosaurs’ early evolutionary success,” says Ramezani, an EAPS researcher. “This gives us some clues to how dinosaurs evolved.”

Keep Reading

Most Popular

A Roomba recorded a woman on the toilet. How did screenshots end up on Facebook?

Robot vacuum companies say your images are safe, but a sprawling global supply chain for data from our devices creates risk.

A startup says it’s begun releasing particles into the atmosphere, in an effort to tweak the climate

Make Sunsets is already attempting to earn revenue for geoengineering, a move likely to provoke widespread criticism.

10 Breakthrough Technologies 2023

Every year, we pick the 10 technologies that matter the most right now. We look for advances that will have a big impact on our lives and break down why they matter.

These exclusive satellite images show that Saudi Arabia’s sci-fi megacity is well underway

Weirdly, any recent work on The Line doesn’t show up on Google Maps. But we got the images anyway.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at with a list of newsletters you’d like to receive.