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Year:
2000
PLACE:
Gadoufaoua, Niger
Expedition members:
17
Fossil in focus:
Sarcosuchus imperator
Age:
middle Cretaceous, some 110 million years ago
Estimated adult length:
40 feet
Estimated weight:
ten tons
Quote:
“To visualize what can’t yet be seen—that’s the key to big fossil discoveries.”
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Go into the bush with Paul Sereno to get up close and personal with SuperCroc.
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SuperCroc
You’ll find interactive maps, models, photos of SuperCroc and bios of paleontologist Paul Sereno and herpetologist Brady Barr on our National Geographic site.
Project Exploration’s SuperCroc Site
Get inside SuperCroc’s head—and take an interactive tour of its skeleton. This site includes tons of information
about the fossil discovery, an extensive image gallery, classroom activities, and interviews with the scientists, sculptors, and artists involved
in bringing SuperCroc to life.
Dinosaur Expedition 2000
Witness paleontology in action! See a firsthand account of the challenges facing Paul Sereno and his team on their four-month expedition to the world’s largest desert and follow their tracks as they find the bones of one of the largest crocodilians that ever lived—an animal they came to call SuperCroc.
Crocodilians
How do crocodiles communicate? Hear juvenile distress calls, threatening adult hisses, and courtship bellows—and learn more about all 23 species of modern crocodilians—at this comprehensive site. Find out how you can help prevent the extinction of the highly endangered Chinese alligator.
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| Photographs by Michael Hettwer |
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This Week’s Questions. Click on a question for a full response.
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| Name: | Peter Irving |
| Subject: | Why so big? |
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| Question 1: |
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| When I heard about SuperCroc, my first thought was: 110 million years ago,
why were so many animals so BIG? |
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| Sereno’s Answer: |
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| Many scientists think that the physiology of dinosaurs was different and the
climate was different, the first being more important than the latter. Mammals are limited in size by their
physiology; dinosaurs may have been warm to the touch and active, but large dinosaurs could not have been as
metabolically active as large mammals, which have never gotten much larger on land than an elephant. Second, we
live in an era of dramatic climate change. I am speaking of the glacial cycles, which extended back some tens of millions
of years. Many large mammals went extinct because of this, even though they were smaller than the dinosaurs. So climate
change has been tough on large animals during the era of mammals. By comparison, the dinosaur era saw no glaciers and
was relatively moderate pole to pole. Many animals back then, however, were the same size as today—they
just don’t get as much press! For example, there were five other croc species living with SuperCroc, three of
which were dwarf species smaller than nearly all living species today. |
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| Name: | Zack Thorpe |
| Subject: | Different lengths |
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| Question 2: |
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| Why are crocs different lengths in different places? |
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| Sereno’s Answer: |
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| Crocs vary in size because they have adapted to different lifestyles and diets.
In Australia the “saltie” [saltwater or estuarine crocodile] is large because it is a predator of large
fish and land mammals; it is capable of swimming in the salty ocean and relocating in distant rivers.
The “freshie” [freshwater crocodile] is smaller and is adapted to life in rivers as more of a
small-fish specialist. These crocs are different sizes because they have different lifestyles, or “niches”;
they do not compete directly with one another. |
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| Name: | Rashka Ebonhand |
| Subject: | Croc Predators |
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| Question 3: |
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| Are there any predators that hunted this croc? |
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| Sereno’s Answer: |
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| Besides other hungry SuperCrocs, it would have run into
Suchomimus, the large spinosaur, as a competitor. I don’t think it had any natural enemies
that would have preyed upon it. |
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| Name: | Bill Unwin |
| Subject: | Male or Female? |
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| Question 4: |
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| Is there any evidence to tell if the SuperCroc you discovered is male or female? If
it was female, that would make a full-grown bull considerably larger. |
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| Sereno’s Answer: |
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| In modern crocs there are almost no clues to the sex of the individual in
its bones. In fact, it is difficult in most cases to tell the sex of a living croc with all its flesh attached! You
need to look closely at its underside. The long-snouted gharials are an exception: The males grow a knob on the tip
of their nose when they reach maturity, but even this knob leaves almost no mark on the skull.
With Sarcosuchus, we knew that it most likely would be impossible to tell male from female with only the fossil
bones at hand. However, if the enlargement of the bony opening for the nose varied in size in adult skulls, we might
guess that the males had large openings and females had smaller ones, using the living gharial as a model. However, so
far we have not noticed any differences in the nose openings—they are all large. |
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| Name: | Diane Benzler |
| Subject: | Life span |
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| Question 5: |
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| How long do you think the life span of these large crocs was? |
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| Sereno’s Answer: |
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| We know it took 50 to 60 years to grow to full adult size. Adults may have
lived as long as a century. |
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