The Dinosaurs of Wyoming - Wyoming State Geological Survey ...

CHAPTER XVII
The Carnivorous Dinosauria and Their Food
Problem
The flesh-eating dinosaurs all possess sharp, flattened, sawtoothed,
cutting teeth and sharp claws on all four feet. The
fore-limbs are always small, incapable of functioning in locomotion,
so that the theropod dinosaurs were bipedal, walking
or leaping with their powerful hind legs, using the heavy tail
as a support, just like modern kangaroos. This group of dinosaurs
has had the longest history of any of the dinosaurian
groups, and they have a wide range in size-some being quite
small and slender, others large and powerful. The Theropoda
are the stem group of the Dinosauria.
The largest and most powerfuL of the many kinds of carnivorous
dinosaurs is that elephantine giant Tyrannosaurus
rex, whose skull is over four feet long (50 inches), and the jaw
has a height of 35 inches. The teeth are flattened, sharp and
numerous. Its body was more than forty feet long and doubtless
had a weight of many tons. It was the most powerful
engine of destruction in the animal world. Five skulls and
complete skeletal material are preserved in the American
Museum of Natural History. One of the skulls was secured
in the Upper Cretaceous of Niobrara County, Wyoming, and
the other material from the Hell Creek Beds of Montana
(Upper Cretaceous).
The theropodous dinosaurs were the makers of the abundant
three-toed footprints (Figure 17a) which are found in the
Triassic of the Connecticut Valley. These dinosaurs ran nimbly
about like birds, setting one foot nearly in front of the
other, so that the prints of the right and left feet are nearly
in a straight line.
Another well-known carnivorous dinosaur from Wyoming
is that form called Allosaurus, with a hind limb taller than a
man, measuring over thirty-four feet long and with' a height
of over eight feet. This skeleton, shown mounted in the American
Museum, feeding on an amphibious dinosaur, has an interesting
history. It is a '\Tyoming treasure, collected in
October, 1879 in the Como Bluffs near Medicine Bow at the
richest locality for dinosaurs, by Mr. F. F. Hubbell, working
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