Skip to Content

Dinosaur Egg Discovery in Argentina Strengthens Nesting and Herding Theories

Although dinosaurs have been extinct for millions of years, discoveries are being uncovered all the time. One such recent unearthing occurred in November 2021 in Argentina and involved a group of dinosaur eggs being found. Why is this finding important?

The dinosaur egg discovery in Argentina is noteworthy due to the sheer number of eggs recovered (more than 100) and the fact that some of the eggs still had embryos. The finding also solidifies the belief that dinosaurs were herding animals, especially the Mussasaurus.

We have lots of exciting matters to talk about ahead regarding this finding. First, we’ll explain what paleontologists found in a lot more detail. Then we’ll discuss the implications of the Argentinian dinosaur eggs and the fossils located near them, so make sure you keep reading! 

New Discovery Of Dinosaur Eggs in Argentina – What Does It Mean?

Argentina remains a hotbed for dinosaur fossils, and other remains, as paleontologists in the southern Patagonian region of Argentina recently found dinosaur eggs believed to have been on the planet for 193 million years.

[playht_player width=”100%” height=”90px” voice=”en-US-Wavenet-J”]

The sheer number of eggs the paleontologists came upon is sure to astound, as there were more than 100 of them. Some of the eggs had embryos, a multicellular organism still early in development. 

In other words, these were going to be dinosaur hatchlings, but they weren’t quite fetuses yet. 

The area where the discovery happened is a dinosaur graveyard, so past dinosaur discoveries have occurred here too (or in the vicinity), but this one takes the cake. 

nesting in herds offered protection against predators - adventuredinosaurs

It wasn’t only dinosaur eggs the paleontologists were lucky enough to find during their latest expedition. They also unearthed nearly 100 bones. The fossils were from dinosaurs of varying ages, including adults and juveniles. 

Were the bones from different dinosaur species? Actually, no! The bones belong to the Mussasaurus, specifically the Mussasaurus patagonicus. Twenty of them assembled into a complete Mussasaurus skeleton of the bones uncovered. That’s tremendous luck.

After dating the bones, the paleontologists realized that the scene they came across in the Patagonian region was age segregation in action. In other words, the eggs were hidden in layers, so they were harder to pick off. The hatchlings were close by in the nest. If the adults weren’t paired up, then they were by themselves. 

The Mussasaurus adults were not found by their young, suggesting that the parents would go out and forage for food to bring back to their hatchlings and juveniles. 

Some experts believe that Mussasaurus dinosaur juveniles remained in the same herd with their parents and dinosaurs until they were old enough to survive and fend for themselves, usually in adulthood. 

While scientists have floated the idea that dinosaurs could have lived in herds even longer, the Mussasaurus discovery provides no evidence to support that.

dinosaurs nested in herds - adventuredinosaurs

So why did the Mussasaurus follow herd behavior? To protect their young and the young dinosaurs of others in the herd, of course. Think about how you would feel like a child with your parents and other adults surrounding you. No one would mess with you, right?

It’s the same kind of theory at play. A dinosaur hatchling is easy pickings to just about any species, but once adults surround that hatchling, the small dino becomes off-limits. 

What Kind of Dinosaur Was the Mussasaurus?

Although the Argentinian discovery of the Mussasaurus eggs and the complete fossil record is quite incredible, the paleontologists involved in this expedition did not discover the Mussasaurus. 

Instead, the species was first uncovered in the 1970s by Jose Bonaparte and his team. They found the fossilized hatchlings and eggs in the Laguna Colorada Foundation in Argentina.

So who was the Mussasaurus, anyway? Its name translates to “mouse lizard.” The Mussasaurus was a sauropodomorph, mostly referring to the dino’s trademark long neck. 

The creature was a known herbivore. It’s estimated the Mussasaurus lived during the Early Jurassic Period about 192.8 million years ago. 

With a name like “mouse lizard,” you’d assume the Mussasaurus was quite small, right? Yet more than likely, it wasn’t. The juveniles would have been small, yes, and it was those juvenile fossils that were the first Mussasaurus discovery. Yet the dino might have been around 20 feet long in adulthood. Its length undoubtedly helped in part due to its neck.

A Mussasaurus infant might have measured about 14.6 inches, which is lizard-sized. The juveniles weren’t nearly as massive or sizable as the adults. 

The Mussasaurus likely had big eyes as well as a shortened snout and a tall head, or it could have grown out of these traits by the time it reached adulthood. Hopefully, the 2021 Mussasaurus expedition findings will reveal more information about this fascinating dinosaur soon, as there’s still plenty to learn! 

Which Dinosaurs Lived in Argentina?

evidence that dinosaurs took care of their young - adventuredinosaurs

The Mussasaurus was one of many dinosaurs that roamed around today’s Argentina. What other famous dinosaurs called this warm and arid land their home over the various species’ millions of years? Let’s take a closer look.


The theropod that was the Giganotosaurus lived during the Late Cretaceous Period’s Cenomanian Age in what later became modern-day Argentina. Fossil records place the dinosaur between 97 and 99.6 million years back.

Discovered in 1993 in Patagonia’s Candeleros Formation, the Giganotosaurus was a carnivore, and quite a big one, at that. It didn’t have a long neck as the Mussasaurus did, but its tail was positively massive. 

The average weight of a Giganotosaurus was 15.2 short tons at most, and the creature might have been up to 43 feet long. Several dinosaur experts believe that the Giganotosaurus might have been larger than Tyrannosaurus rex, but they were probably about the same size. 


Nicknamed the La Amarga lizard, the Amargasaurus lived during the Early Cretaceous Epoch anywhere from 122 to 129 million years ago. Fossils of the Argentinian dinosaur were first uncovered in 1984.

Much smaller than the other dinosaurs we’ve discussed in this article, the Amargasaurus measured about 33 feet long. It might have weighed no more than 2.9 short tons. Its neck was long but nothing like the Mussasaurus’ neck. Instead, the extra neck length correlated to the size of the rest of the Amargasaurus’ body. 

Of course, we have to talk about the neural spines that covered the Amargasaurus’ anterior dorsal vertebrae and neck. The spines grew taller as they progressed down the dinosaur’s back, and at their tallest were 24 inches. 


The sauropod known as the Argentinosaurus makes it clear where it hails from, indeed Argentina. 

This dinosaur from the Late Cretaceous Period was bigger than all the dino species we’ve listed so far and might be one of the biggest land mammals, period. 

According to experts, the Argentinosaurus was 110 short tons and 130 feet long. The dinosaur’s remains were first uncovered in 1987 by a farmer. Today, we have a reconstructed skeleton to go from. 

Where did the bulk of the Argentinosaurus’ length come from? That would be its very long neck, which almost seemed out of sync compared to the rest of its shorter body. The tail was skinny by comparison, although still long. 


The Patagotitan was found in Patagonia’s Cerro Barcino Formation near the Chubut Province. A newer dinosaur that wasn’t uncovered until 2008, more discoveries are still being made about the Patagotitan all the time. 

Like the Mussasaurus, the Patagotitan has an exceedingly long neck. Its tail was equally sizable. This dinosaur might have been 131 feet long, which is very massive! The estimated weight of the Patagotitan is 85 tons. 

The dinosaur possessed a lamina prezygodiapophysealis along several vertebrae in its back. It is a vertical ridge. Neural spines, also vertical, were present nearer the back vertebrae. 

Did Dinosaurs Live in Herds?

Earlier, we talked about herding behavior among the Mussasaurus, and how the fossils were grouped suggests that the adults looked after the young. Surely, this isn’t a trait unique to the Mussasaurus, right?

That is correct. The Massachusetts Institute of Technology or MIT was involved in a study with South African and Argentinian researchers that looked more into herding behavior. The data was published in an October 2021 edition of the journal – Scientific Reports.

The researchers found that herding behavior in dinosaurs could have gone back as far as 192 million years ago. That’s a difference of 40 million years from other documented cases of dinosaur herding. 

A 2019 post from the Australian Museum suggests a point that makes lots of sense: herbivores outside of the Mussasaurus likely grouped together for safety’s sake. After all, since they’re not meat-eaters, carnivorous dinosaurs might regard herbivores as easy prey.

When the number of prey dinosaurs is greater than the lone predator, the predator knows they can’t win. If the predator is outsized as well–they would be in a group versus a lone dinosaur–the predator will back off.

The Australian Magazine piece suggests that carnivores could have herded as well. The meat-eating dinosaurs might have grouped into small packs. There, they’d form mini-communities of sorts, raising juveniles and displaying social traits, at least according to experts.

Anyone’s guess is which carnivorous dinosaurs in the community would have hunted and what the pecking order could have been. Hopefully, someday we’ll know for sure. (Source)

Many creatures that exist today that come from dinosaurs also exhibit herd behavior. The crocodile might be a solitary creature, but its hatchlings grow in groups with the protection of one adult.

Lions assemble into groups of up to 40 other lions. Interestingly, it’s the lionesses that hunt, not the lions. 

How Does This Discovery Support Dinosaur Nesting and That They Took Care of Their Young?

Long before dinosaur experts and enthusiasts were raving about the Mussasaurus and its herd tendencies, there was the Maiasaura, whose name means “good mother lizard” in Latin. The species was a duck-billed dinosaur estimated to have lived during the Upper Cretaceous Period roughly 76.7 million years back.

A 30-foot dinosaur, the Maiasaura fossils were uncovered in 1978, protected embryos and eggs as part of a nesting colony. This discovery told paleontologists that the Maiasaura fed her young in their nest. 

It was huge news, as no dinosaur was ever proven to exhibit that behavior before. And now, with what we’re finding out about the Mussasaurus through the Argentinian eggs and fossil records, it appears we might have a second example of nesting. 

Although we can’t say for sure whether the Mussasaurus also fed its young in their nest, hopefully, we’ll have clearer answers on that point soon. 

These parallel discoveries decades apart raise some interesting questions. Suppose the proximity of dinosaur bones to eggs is part of what indicates a dinosaur species might have cared for its young. Could we go back and reevaluate other dinosaur egg findings to determine what the parent dinosaur could have been doing, such as foraging or feeding young?

More than likely, the Maiasaura and Mussasaurus are just the tip of the iceberg. It makes sense that adult dinosaurs would have taken care of their young to ensure the survival of their species. Just because we don’t have evidence of it doesn’t mean it happened. (Source)

Both herbivores and carnivores are proven to have lived in groups. Part of the responsibility of those groups likely included hatchling and juvenile care. 

We’ll always have to wait on more findings, but the data now points towards many dinosaurs caring for their young as part of herding behavior. 


Recently, a dinosaur called the Mussasaurus was discovered to have likely lived in herds and potentially cared for its young as well. It is based on eggs (some with embryos) and fossil records just uncovered in Argentina. 

We can now take this exciting information and apply it to other dinosaurs to discover which species might have herded and raised hatchlings. It’s probably more than anyone realizes!