The centerpiece of our exhibition is Mamenchisaurus hochuanensis (Mah-MEN-chi-SAWR-us ho-CHOO-an EN-sis). Inside this traveling exhibition, you’ll get to discover her both as she looked in life, and as she would have looked had scientists been able to peer inside her body. Each view holds clues to a fascinating scientific question: How did these dinosaurs get so big?
No one has ever seen inside a sauropod. After all, flesh doesn't fossilize. But today's experts are making science-based reconstructions of the biological systems that allowed members of this group to become the largest animals that ever walked.
By understanding how these ancient giants chewed--or didn't chew!--how their digestion worked, how they breathed, scientists are coming closer to unraveling the mystery of size.
There's no getting around it: sauropods did have small brains in their small heads. And those big bodies make the brains seem even smaller. Surprisingly, though, the brains of most living reptiles are just as small when compared to their body size. And whatever their brain size, sauropods were smart enough to be the dominant plant-eaters on the planet for 140 million years.
Elephants must feed for 18 hours a day. Sauropods could be could be 10 times elephant-size, or more, so how did they find enough hours in the day to feed? The answer may surprise you. With their tiny skulls and tiny teeth, they were huge--and hugely efficient--eating machines.
A heart is an amazing organ, whether beating in a hummingbird, a human or a sauropod. The bigger the animal, the bigger and more powerful this biological pump must be. But how big can a heart get? And how does the long sauropod neck complicate the heart's job?
Most likely you won't even recognize the lungs of Mamenchisaurus as lungs, they're so different from yours. And the lungs were just one part of a complex, highly efficient breathing system like the one found in birds today. The efficiency of this system was key to the gigantic size of sauropods.
How much food did these giants need? That depends on how much energy they used. Scientists are trying to figure out if sauropods had metabolisms more like modern mammals and birds, which need a lot of energy to sustain themselves, or like snakes, lizards and turtles, which use relatively little energy.
Long necks were a key reason sauropods were able to get so big. Long necks let the animals reach foods other plant eaters couldn't, and meant the animals could stand in one place while practically inhaling food from a large swath of landscape. But as useful as they were, long necks had some big potential downsides. One of them was immense weight.
For 140 million years, sauropods roamed Earth--but today we have just fossils to tell us about what these animals looked like from the outside. How big were they? How big were their young? What did their skin look like? How fast could they move? And while fossils can't answer every question--like what color the animals were--they do reveal an astonishing amount of information that helps paleontologists understand these massive creatures.
All dinosaurs reproduced by laying eggs, just as living birds and many modern reptiles do. But surprisingly, the babies that hatched out of sauropod eggs were generally no bigger than a modern adult goose. Sauropods didn't start out extremely big--they just grew very, very fast.
As amazing as it seems, we have footprints of sauropods on nearly every continent, left during their 140-million-year stint on Earth. And those footprints, many in long trackways, provide some of the best data on the animals' daily life. With them, scientists can tackle such questions as: How fast could these animals walk? Did they travel in groups? Did young and old move together?
Sauropods came in different sizes--most of them big. An adult female Mamenchisaurus would have weighed about 13 tons (12,000 kilograms). That may sound big, but it's actually below average for sauropods.
In humans, skin is the biggest organ--an average adult's skin weighs as much as a gallon of milk. The skin of an adult Mamenchisaurus weighed about as much as a small car.