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Mamenchisaurus
hochuanensis

OLogy Series
extinct animal
card
340

Mamenchisaurus
hochuanensis

OLogy Series
extinct animal

Sauropods weren't just the largest dinosaurs. They were also the largest animals to ever live on land. The sauropod Mamenchisaurus (Mah-MEN-chi-SAWR-us) lived about 160 million years ago. Like other sauropods, it had a long, flexible, and surprisingly light neck. Although it wasn't the biggest sauropod, it had the longest neck for its body size of any other dinosaur. It could have reached lots of plants while standing in one place.

The head of an African elephant head weighs about 1,000 pounds. The head of Mamenchisaurus weighed:

4,500 pounds

450 pounds

45 pounds

Are you right?

Correct!

Like all sauropods, Mamenchisaurus had a small head. Small, light heads can be an advantage: long necks were able to support them. And even though their brains were small, they were "big enough" for them to find food and herd young.

Being big is hard work! The heavier an animal, the more energy it uses and the more it needs to eat. When its length doubles, its weight:

doubles (weight x 2)

is squared (weight x weight)

is cubed (weight x weight x weight)

Are you right?

Correct!

Say a young 40-foot-long sauropod weighed 3 tons. By the time it grew to 80 feet, it would have weighed around 27 tons (3 x 3 x 3 = 27)! Sauropods were about as big as land animals can get. Blue whales may be larger, but they have water to support their bulk.

Mark Norell, paleontologist

It makes sense that sauropods breathe like modern-day birds. After all, sauropods and birds descended from the same common ancestor.

Mark Norell, paleontologist

The neck of Mamenchisaurus was more than 30 feet (9 meters) long. That's about half its total length! Air pockets in the neck bones kept the neck amazingly light.

When the baby Mamenchisaurus hatched, it wasn’t much bigger than you were as a baby.

Fact
or
Fiction
?

Fact

Sauropods didn't start out extremely big. They just grew very, very fast. A hatchling would double its size in just 5 days! An adult Mamen-chisaurus was 10,000 times its birth weight.

Very different than mammal lungs, sauropod lungs worked like those of living birds.

Fact
or
Fiction
?

Fact

With big lungs and air sacs, sauropods could get lots of oxygen from each breath, much more than humans can!

Huge animals like Mamenchisaurus had to eat a lot to get big. They spent all day chewing.

Fact
or
Fiction
?

Fiction

Sauropods didn't waste time chewing. They swallowed their food whole! Their stomachs functioned like giant compost heaps. It took as long as two weeks to digest tough plants.

Lived: Jurassic Period, about 160 million years ago, in what is now China
Size: 60 feet (18 m) long; 13 tons (11,800 kg)
Diet: about 1,150 pounds of plants a day!
Reproduction: laid eggs
Social Behavior: possible herding
Cool Fact: Sauropods might have been brightly colored, like many modern-day birds and reptiles.
Cool Fact: Sauropods may have released around 13 gallons (50 l) of gas per day.

Image credits: © Raúl Martin; Mark Norell: AMNH; Mark Norell: AMNH.