It’s one of the first things visitors see when they enter the Academy of Natural Sciences: measuring up to 42 feet in length and weighing in at an estimated 7.5 tons, Tyrannosaurus rex was one of the largest predators to ever walk the Earth.

This impressive animal is one of many dinosaurs and other Mesozoic creatures you’ll encounter in Dinosaur Hall. More than 30 species are represented, about half of which are full skeletal mounts, including Avaceratops, Chasmosaurus, Corythosaurus, Deinonychus, Pachycephalosaurus, Tenontosaurus, and Tylosaurus.

In addition to the skeletons, visitors can view dinosaur eggs, footprints, sculptures, murals, paleontologist tools, a life-size model showing the internal anatomy of a Stegosaurus, and a green-screen video studio where they can project their own images into a world full of dinosaurs.

Denizens of Dinosaur Hall

More than 30 species of dinosaurs and other Mesozoic reptile can be found in the Academy's Dinosaur Hall. Click on one of the species names below to see illustrations by paleo-artist Robert F. Walters and find out more about some them.

• Chasmosaurus
• Avaceratops
• Corythosaurus
• Deinonychus
• Elasmosaurus
• Pachycephalosaurus
• Tenontosaurus
• Hadrosaurus
• Torosaurus
• Tylosaurus
• Tyrannosaurus Rex

Illustration by Robert F Walters

Chasmosaurus belli

Pronunciation:

KAZ-mo_SORE-us, BELL-eye

Meaning of name:

Bell's open lizard

Length:

17 feet (5 meters)

Weight:

Estimated 2 tons (1,800 kg)

Diet:

Plants

Range:

North America (Alberta)

Age:

Late Cretaceous, 76-73 million years ago

What's real?:

This mount is a cast of the original at the Canadian Museum of Nature.

What is it?

Chasmosaurus is a ceratopsian (horned dinosaur).

Illustration by Robert F Walters

Avaceratops lammersi

Pronunciation:

AY-va-SARE-ah-tops LAMM-urz-eye

Meaning of name:

Ava's horned face, of the Lammers

Length:

7 feet (2 meters)

Weight:

Estimated 400 pounds (180 kg)

Diet:

Plants

Range:

North America (Montana)

Age:

Late Cretaceous, 76 million years ago

What's real?:

The skeleton is a cast. The original bones are kept in the Academy's research collection for study.

What is it?

Avaceratops is a ceratopsian or horned dinosaur.

Illustration by Robert F Walters

Corythosaurus casuarius

Pronunciation:

core-ITH-oh_SORE-us, CASS-oo-WARE-ee-us

Meaning of name:

Helmeted lizard, like a cassowary bird

Length:

30 feet (9 meters)

Weight:

Estimated 3 tons (2,700 kg)

Diet:

Plants

Range:

North America (Alberta)

Age:

Late Cretaceous, 76-73 million years ago

What's real?:

Most of this fossil skeleton is real. The skull is a cast of an original Corythosaurus skull from the Royal Ontario Museum in Toronto.

What is it?

Corythosaurus is a hadrosaur (or duckbill) dinosaur.

Illustration by Robert F Walters

Deinonychus antirrhopus

Pronunciation:

dye-NON-ick-us, ant-er-ROPE-us

Meaning of name:

Terrible claw, counterbalanced

Length:

9.5 feet (3 meters)

Weight:

Estimated 175 pounds (80 kg)

Diet:

Meat

Range:

North America (Montana, Wyoming)

Age:

Early Cretaceous, 115-105 million years ago

What's real?:

This is a cast of the original fossil material at Yale University.

What is it?

Deinonychus is a theropod dinosaur.

Illustration by Robert F Walters

Elasmosaurus platyurus

Pronunciation:

ee-LAZ-mow-SORE-us PLAT-ee-YOUR-us

Meaning of name:

thin-plated lizard with flat tail

Length:

42 feet (13 meters)

Weight:

Estimated at 2.3 tons (2,100 kg)

Diet:

Meat

Range:

North America (Kansas)

Age:

Late Cretaceous, 82 million years ago

What's real?:

This mount is a cast. The original fossils are in the Academy's research collection for study.

What is it?

Elasmosaurus is not a dinosaur. It is a plesiosaur, a marine reptile.

Illustration by Robert F Walters

Hadrosaurus foulkii

Pronunciation:

HAD-row_SORE-us, FOLK-eye

Meaning of name:

Foulke's bulky lizard

Length:

23 feet (7 meters)

Weight:

Estimated 2.5 tons (3,200 kg)

Diet:

Plants

Range:

North America (New Jersey)

Age:

Late Cretaceous, 73 million years ago

What's real?:

The bones from this mount are cast from the original fossils, which are in the Academy's research collection for study.

What is it?

Hadrosaurus is a hadrosaur (or duckbill) dinosaur.

Illustration by Robert F Walters

Pachycephalosaurus wyomingensis

Pronunciation:

PASK-ee-SEFF-uh-low-SORE-us, wyy-OME-ing-EN-sis

Meaning of name:

Thick-headed lizard from Wyoming

Length:

9 feet (3 meters)

Weight:

Estimated 250 pounds (115 kg)

Diet:

Plants

Range:

North America (Alberta, Montana, South Dakota, Wyoming)

Age:

Late Cretaceous, 68-65 million years ago

What is it?

Pachycephalosaurus belongs to a group of dinosaurs called pachycephalosaurs (domed dinosaurs), which are related to ceratopsians (horned dinosaurs).

Illustration by Robert F Walters

Tenontosaurus tilletti

Pronunciation:

teh-NON-toe_SORE-us, TILL-et-eye

Meaning of name:

Tillett's tendon lizard

Length:

23 feet (7 meters) for adults. The larger skeleton in the museum is a juvenile (13 feet or 4 meters). The smaller ones are young.

Weight:

Estimated 1,500 pounds (680 kg)

Diet:

Plants

Range:

North America (Montana, Utah, Wyoming)

Age:

Early Cretaceous, 115-105 million years ago

What is it?

Tenontosaurus is a dinosaur that is probably related to Iguanodon.

Illustration by Robert F Walters

Torosaurus latus

Pronunciation:

TORE-oh_SORE-us, LATT-us

Meaning of name:

Wide perforated lizard

Length:

25 feet (7.5 meters)

Weight:

Estimated 6 tons (5,400 kg)

Diet:

Plants

Range:

North America (Wyoming, Montana, Saskatchewan)

Age:

Late Cretaceous, 68-65 million years ago

What's real?:

The skull is made up of real fossil but the missing parts are made of plaster.

What is it?

Torosaurus is a ceratopsian (horned dinosaur). Recent research by Jack Horner and his colleagues indicates that Torosaurus latus is not a true species. Instead, these fossils are probably from older individuals of Triceratops horridus.

Illustration by Robert F Walters

Tylosaurus prorigor

Pronunciation:

TIE-low-SORE-us pro-RIG-or

Meaning of name:

Knot lizard, stiff in front

Length:

43 feet (13 meters)

Weight:

Estimated 2 tons (1,800 kg)

Diet:

Fish, ammonites, other marine reptiles

Range:

North America (Kansas)

Age:

Late Cretaceous, 85-78 million years ago

What's real?:

The skeleton is a cast of the original at the Kansas University Museum of Natural History

What is it?

Tylosaurus is a mosasaur and not a dinosaur. It's related to monitor lizards.

Illustration by Robert F Walters

Tyrannosaurus rex

Pronunciation:

tie-RAN-oh-SORE-us REX

Meaning of name:

tyrant lizard, king

Length:

35-40 feet (10-12 meters)

Weight:

Estimated 6 tons (5,500 kg)

Diet:

Meat

Range:

North America (Alberta, Colorado, Montana, New Mexico, Saskatchewan, South Dakota and Wyoming)

Age:

Late Cretaceous, 68-65 million years ago

What's real?:

The skeleton and skulls are casts. The original fossils are in the American Museum of Natural History in New York.

What is it?

Tyrannosaurus is a theropod dinosaur.