Barosaurus: A Giant Herbivore of the Late Jurassic Era

Barosaurus: A Giant Herbivore of the Late Jurassic Era

Barosaurus, whose name translates to ‘Heavy Lizard’, roamed the Earth during the Late Jurassic Period, approximately 155.7 to 145.0 million years ago. It is a member of the diplodocid family within the group Sauropoda . Like all sauropods, it was an herbivore, navigating its environment on all four legs. Despite its immense size, many aspects of its physical dimensions remain a subject of ongoing research and debate.

Barosaurus Key Facts

Meaning of nameHeavy Lizard
Type SpeciesBarosaurus lentus
When it Lived155.7 to 145.0 MYA
PeriodLate Jurassic
EpochLate/Upper Kimmeridgian to top of the Early/Lower Tithonian
Length82.0 to 89.0 feet
Height23.0 feet
Weight13.0 to 22.0 tons
First Discovery1889 by E. R. Ellerman
Described by1890 by Othniel Charles Marsh
HolotypeYPM 429
Location of first findMorrison Formation, South Dakota
Also found inColorado, Utah, Wyoming, Zimbabwe

Barosaurus Origins, Taxonomy and Timeline

Barosaurus, a name derived from Greek words ‘barys’ meaning heavy and ‘sauros’ meaning lizard, displayed many of the hallmark features characteristic of diplodocid sauropods. In addition to their great size, long-necks, quadrupedal posture and herbivorous diet, diplodocids are also famous for the long “whiplash” tails that many members of the group possessed (more on that below). In fact, “diplodocid” roughly translates as ‘double beam lizard’’ – a reference to the how the neck and tail of these animals would have appeared as great dual “beams”, extending for meters and meters from the solid support of the trunk and legs.   

A detailed illustration of Barosaurus, created by Ritterbush, showcasing the dinosaur's distinctive long neck and tail. The Barosaurus is depicted in a side profile with a brown and gray coloration, emphasizing its massive size and elongated body structure.

Barosaurus lived during the Late/Upper Kimmeridgian to Early/Lower Tithonian Epochs of the Late Jurassic, a time frame spanning from 155.7 to 145.0 million years ago. This era was a period of significant evolutionary development and diversification for dinosaurs, particularly for the massive sauropods.

Discovery & Fossil Evidence

The discovery of Barosaurus was a landmark event in the field of paleontology. Unearthed in 1889 in the Morrison Formation of South Dakota, it provided a new window into the world of the largest of the dinosaurs: the gigantic sauropods. E. R. Ellerman’s discovery was later described in detail by Othniel Charles Marsh in 1890, adding a significant piece to the puzzle of dinosaur evolution.

Subsequent finds in regions like Colorado, Utah, Wyoming, and potentially even as far afield as Zimbabwe, have broadened our understanding of this dinosaur’s geographical range. The holotype, YPM 429, remains a crucial reference point for researchers studying this species.

The fossils of Barosaurus, primarily consisting of skeletal remains, offer insights into its size and structure. The degree of preservation varies across different specimens, but each find contributes valuable information about this ancient giant. Notable specimens have helped paleontologists piece together a more comprehensive picture of its physical characteristics and lifestyle.

Barosaurus Size and Description

Imagine a creature so colossal that its mere presence commands attention. This was Barosaurus, a dinosaur whose physical attributes were nothing short of awe-inspiring. Picture a long, serpentine neck, a feature that immediately sets it apart from many of its contemporaries. This neck, combined with a similarly elongated tail, gave it a strikingly unique silhouette among the giants of the Jurassic. The function of the highly elongate diplodocid ‘whiplash’ tail has been debated for years – with everything from defense to interspecific signaling suggested.

Barosaurus was a quadruped, moving placidly on all four of its sturdy legs. Its locomotion likely involved a slow, deliberate movement, befitting its massive size. The sheer size and structure of this dinosaur suggest it was not built for speed, but rather for putting away as much food as its prodigious stomach would allow. While its long neck might lead one to think it was adapted for reaching high vegetation that other herbivores couldn’t access, it is now thought that some sauropods like Barosaurus actually utilized their necks in a side-to-side sweeping motion, foraging as many lower-level plants as possible without having to move its great bulk needlessly around. This feature speaks volumes about the range of adaptive strategies practiced in the diverse ecosystems of the Late Jurassic.

Size and Weight

This image depicts a size comparison chart of Barosaurus lentus, a massive sauropod dinosaur, alongside a human for scale. The chart highlights the immense size of Barosaurus lentus, with an estimated length of 10 meters or more. The orange silhouette of the dinosaur contrasts with the grid background, emphasizing the proportions of its elongated neck and tail.
Slate Weasel, CC0, via Wikimedia Commons

Barosaurus was an enormous animal, even by dinosaur standards. Adult specimens of this species stretched to an impressive length of about 82.0 to 89.0 feet. To put this in perspective, that’s about as long as three school buses lined up end to end! When it comes to weight, these giants tipped the scales at approximately 13.0 to 22.0 tons.

The sheer size of Barosaurus is not just a number; it’s a testament to the incredible biodiversity and ecological dynamics of the Jurassic Period. This size also indicates the abundance of resources available in its habitat, as sustaining such a massive body would require a significant amount of food. The colossal stature of Barosaurus not only highlights its physical dominance in its environment but also underscores the fascinating evolutionary journey of Sauropoda.

Contemporary Dinosaurs

In the lush, prehistoric world where Barosaurus roamed, life was a constant dance of survival and coexistence. Picture this: Barosaurus, a gigantic, long-necked dinosaur, towering above the ferns and cycads. This gentle giant, with a neck that seemed to stretch forever, lived alongside some fascinating contemporaries. One of them, Allosaurus, was like the outlaw of the Jurassic Period. Smaller than Barosaurus but fierce and agile, Allosaurus might have eyed the young or weak members of the Barosaurus herd, calculating if it could make a meal out of them. The thought of a showdown between these two is enough to send shivers down anyone’s spine!

This artistic rendering depicts a dramatic scene featuring a Barosaurus, a long-necked sauropod dinosaur, defending itself against three attacking theropods in a lush, prehistoric forest. The towering Barosaurus stands on its hind legs, its elongated neck arched high above the ground, while the agile theropods circle around it.
Fred Wierum, CC BY-SA 4.0, via Wikimedia Commons

But not all interactions were about predator and prey. Take close relative Apatosaurus, for instance. These two giants likely crossed paths, perhaps competing for the juiciest leaves or the best sunny spots to bask in. Imagine two skyscrapers moving side by side, their massive bodies casting shadows over the forest floor. Yet, despite their size, there was a certain grace in their movements, a peaceful coexistence in their shared habitat.

Then there was Amphicoelias, a mysterious giant, rumored to be even larger than Barosaurus. If these two behemoths met, it would be like two titans sharing the same stage, each commanding respect due to their sheer size. Their interaction, likely more of a gentle acknowledgement than a fierce competition, would be a sight to behold, a testament to the diversity and grandeur of prehistoric life.

Lastly, Brachiosaurus, another contemporary, was possibly Barosaurus’ complement in the world of giants. With its longer front legs and high shoulders, Brachiosaurus represented a different take on the theme of ‘huge herbivore’, possibly targeting the higher browse while leaving the lower lying vegetation to Barosaurus and its kin.

Interesting Points about Barosaurus

Barosaurus in its Natural Habitat

Barosaurus thrived in a world vastly different from ours. During the Late Jurassic Period, it inhabited environments that were lush and rich in vegetation. The climate was likely warm and humid, supporting a diverse array of plant life, which formed the primary diet of this herbivorous giant.

As a herbivore, Barosaurus would have spent much of its time foraging for food, stripping vegetation with its thin, needle-like teeth – no need to chew! Setting itself up at the fern and conifer buffet, it would have let its singularly long neck do much of the “walking” until it was time to move on to the next spot. This was a finely tuned strategy that balanced food intake against energy expenditure – a feeding behavior that likely had a significant impact on the landscape, possibly shaping the vegetation profile of its habitat.

The social behavior of Barosaurus is a subject of speculation. Whether it was a solitary wanderer or moved in herds, its presence would have had a considerable impact on its ecosystem. Its size alone would have influenced predator-prey dynamics, and its feeding habits could have played a role in shaping the plant community.

Frequently Asked Questions

What era did this dinosaur live in?

Barosaurus thrived during the Late Jurassic Period, specifically from the Late Kimmeridgian to the Early Tithonian Epochs, which translates to about 155.7 to 145.0 million years ago.

How was this dinosaur first discovered?

The first discovery of I was made in 1889 by E. R. Ellerman in the Morrison Formation, South Dakota. It was subsequently described in 1890 by Othniel Charles Marsh.

What type of diet did it have?

As a herbivore, Barosaurus primarily fed on plant material. Its long neck would have been advantageous in targeting plant material from a stable standing position – similar to the long arm of a multi-ton digger on a modern construction site!

Where else, besides its initial discovery location, have fossils been found?

Beyond its initial discovery in South Dakota, fossils of Barosaurus have also been unearthed in Colorado, Utah, Wyoming.

What family does this dinosaur belong to?

Barosaurus is a member of the Diplodocid family, a group known for their distinctively long necks and tails, and a specialized herbivorous diet.

What does its name mean and how is it pronounced?

The name Barosaurus translates to “Heavy Lizard,” derived from the Greek words ‘barys’ meaning heavy, and ‘sauros’ meaning lizard. It is pronounced as BAH-roe-SORE-us.


The information in this article is based on various sources, drawing on scientific research, fossil evidence, and expert analysis. The aim is to provide a comprehensive and accurate overview of Barosaurus. However, please be aware that our understanding of dinosaurs and their world is constantly evolving as new discoveries are made.

Article last fact-checked: Joey Arboleda, 11-28-2023

Featured Image Credit: Kathleen A. Ritterbush, CC BY-SA 4.0, via Wikimedia Commons