Fossil Friday: Camarasaurus

This Apatosaurus is Louise. She's a good friend of Ajax.

Species: Camarasaurus lentus (Ka-ma-ra-sore-us lent-us)

What it means: Chambered lizard

Other Species: C. supremus, C. grandis, and C. lewisi

Where I live: Western U.S.A.- The Morrison Formation

When to find me: The Late Jurassic period, about 155-145 million years ago.

My favorite food: Plants! I’m an herbivore.

Most Apatosaurus wouldn't be quite as large as some sources portray them. That said, they're still enormous! This one is a modest size, just small enough to tickle her belly.

My neighborhood: The Morrison Formation covers a huge expanse of land with a variety of different habitats teaming with life. Most of it was very much like the Serengeti of modern day Africa, only with prairies of drought-tolerant ferns and cycad relatives instead of grass. Dense woodlands of tall conifers like the modern araucaria, ginkgoes, and tree ferns would only lie in places of plentiful water such as the few permanent rivers. Other areas had far more sparse and shrubbier vegetation like the open woodlands of acacia trees in the Serengetti.

Life in this environment would’ve adapted to long months of harsh drought, followed by a few months of monsoon that flooded the rivers. Many of the larger herbivores may have migrated like the herds in Africa do today, while most carnivores stayed behind to feast on the dead and dying, or else become opportunistic hunters of less traditional diets for lean times, such as fish or turtles in the rivers.

A few of my neighbors: First let me share my herbivorous friends…

  • Long-necked sauropods like Apatosaurus, Brachiosaurus, Diplodocus, Barosaurus, Suuwassea, Supersaurus, Haplocanthosaurus, and Dystrophaeus.
  • Armored dinosaurs like Stegosaurus, Hesperosaurus, Mymoorapelta, and Gargoyleosaurus.
  • Two-legged ornithopods like Dryosaurus, Camptosaurus, and Nanosaurus

The predators in the neighborhood include dinosaurs like Allosaurus, Torvosaurus, Ceratosaurus, Saurophaganax, Marshosaurus, Stokesosaurus, Ornitholestes, Coelurus, Tanycolagreus, Elaphrosaurus, and Koparion.

Plus there are all the tiny critters on the ground I try not to step on…countless lizards, crocodile relatives on land and water, mammals, frogs, turtles, fish. Some of the pterosaurs flying in the sky help me with any bugs that might try to bite me.

Fun Facts:

  • Camarasaurus gets its name from the greek kamara (vaulted chamber) + sauros (lizard). This was to describe the hollow spaces in its vertebrae, or back bones.
  • Camarasaurus was the most common dinosaur in the Morrison Formation, like zebras in Africa!
  • Many paleontologist think that Camarasaurus ate some of the tougher plants in the area. It wouldโ€™ve reached for trees as tall as 20 ft, but may have preferred rough shrubs no taller than 6 ft. Tough plants wear down the teeth quickly, and preferred browsing height can be guessed by looking at the dinosaurโ€™s neck.
  • Why are there so many species of Camarasaurus living in the same area as so many other kinds of sauropods? Some paleontologists think that a few species of Camarasaurus are a direct line of relatives. C. grandis was found in the oldest layers of rock. C. lentus appeared later, and lived alongside C. grandis for several million years until its older cousin died out. Then C. lentus disappeared, just in time for C. supremus to walk on stage.
  • Camarasaurus supremus was the largest species. Nearly twice as big as Camarasaurus lentus pictured in the size comparison!
  • Camarasaurus lewisi has waffled between being described as a species of Camarasaurus and an entirely new animal, Cathetosaurus. As of 2013 it was officially determined to be different enough that Cathetosaurus is a valid genus. It was very similar in size and build to C. grandis and C. lentus, though it appeared later and was a bit smaller.
  • Camarasaurus eggs have been found in long lines. Apparently the big mamas just laid their eggs as they walked and left them there! Perhaps they were buried in a sort of trench. Either way, the eggs were abandoned afterwards.
  • Older Camarasaurus traveled in herds.

Fossil Finds: Hundreds of individuals, tracks, eggs… We have a great picture of how these animals lived, and can even learn about other animals in the area, like Allosaurus.


Mateus, O., & Tschopp E. (2013). Cathetosaurus as a valid sauropod genus and comparisons with Camarasaurus. Journal of Vertebrate Paleontology, Program and Abstracts, 2013. 173.

Foster, John. Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press, 2007

“Camarasaurus.” Wikipedia,

4 thoughts on “Fossil Friday: Camarasaurus

  1. By far the cutest (and squishiest) sauropods–camarasaurus needs more love. ๐Ÿ˜€ Haha, that face of the one in the back! And me likes the speckles. :3

    You may have already mentioned this in a previous post, but did sauropods have digestive systems similar to modern herbivores, with chambered stomachs? At first I thought that’s what “chambered” referred to in camarasaurus’ name, but it’s interesting to know that it’s actually referring to spaces in the vertebrae. ๐Ÿ™‚

    Also, going back to previous posts, I really like the read-aloud story you posted on Youtube! There’s something about hearing a story aloud that really adds to it. Eventually, maybe it would be cool to even add subtle sound effects in the background? And Gulper’s comic was so cute! The Pixar-esque watercolor look was perfect for the story, and you did a good job of making Gulper look massive compared to the poor little fish.


    1. Hehe, I love Camarasaurus! Though I must admit the squishiness is my personal interpretation. ๐Ÿ˜€ I read a post by Mark Witton at one point speculating that Camarasaurus may have had fat reserves for long journeys during drought. How could a prehistoric savanna support so many huge herbivores? Camarasaurus were everywhere! And that’s not even starting to think about all the other equally huge and even bigger sauropods that lived right alongside them. It’s just mind boggling how much vegetation all those giants were eating. Supposedly cycads and conifers like araucarias are slow growing too, which makes no sense at all. How could they all live in one place!?

      Lol, tangent there. ๐Ÿ˜€

      I honestly don’t know much about sauropod digestive systems, so it’s a good thing I have a book all about it. ๐Ÿ˜€ It appears that sauropods would’ve had similar digestive systems to an elephant. Not a multi-chambered stomach, like cattle, but a huge and complex intestinal system. I always thought they had a gizzard of sorts because of talk of gastroliths (swallowed rocks that help break up food), but perhaps the gastroliths are in the stomach, and not a gizzard in this case.

      I’m glad you like the read aloud. ๐Ÿ˜€ It would be really cool to make them all fancy, perhaps with some super basic “animated” elements (book trailer style, not actually animated), background music, and sound effects. At the moment I’m trying to figure out what I can do with the super limited program I have. I think I need to see what I can find for the desktop instead of the iPad.

      Thank you for stopping by! ๐Ÿ˜€

      Liked by 1 person

  2. Interesting. It never occurred to me that a dinosaur might try to eat a turtle. I am having trouble trying to image where the spaces were in the vertebrae. Do you have a picture or can you sketch one?


    1. Turtles were extremely common in the Morrison Formation! I’m sure larger carnivores like Allosaurus or Torvosaurus would take any chance they could to catch one off guard during a drought. They have a bite force strong enough to crush the shell. This may only have happened during desperate times though, since there are easier ways to get a more substantial meal. ๐Ÿ™‚ Unless of course the turtle was squished by a passing sauropod!

      I didn’t quite know what the chambered thing meant either aside from some nebulous idea of spaces in the bones, so I looked it up. ๐Ÿ™‚ The best way I can explain it without pictures is that there are more fenestra in the bones than you see in mammals. In mammals, you mostly just see the space through the center of the vertebrae that allows the spinal chord through, along with a few other “holes” along the wing-like projections of the vertebrae for large nerves and tendons to attach to. Sauropods like Camarasaurus have much larger spaces, and more of them, particularly to allow space for air sacs along the bottom of the vertebrae. The link below is a picture of the extended lung system, or pulmonary system, of sauropods.

      Mammals have a very simple raspatory system. We have one set of lungs and we use them to breath in and out. Birds have far more complex raspatory systems. They have a set of lungs, but also extended airspaces connected to those lungs somehow (I still don’t fully understand it). They breathe in, and never have to have the carbon dioxide travel back out the same direction like mammals do. They do exhale carbon dioxide, but it’s a one way road instead of turning back on itself like mammals do. The extension of the lungs allows for greater and more efficient absorption of oxygen, and provides strength to the bones even though they have less mass overall. Both things a great feature to have when you’re as massive as a sauropod!


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