PREDATOR OR SCAVENGER?

PREDATOR OR SCAVENGER?
Introduction
With teeth as big as bananas, Tyrannosaurus rex could have been the
fiercest predator on earth―but was it? Some paleontologists argue
that T. rex may have actually been a scavenger, feasting on animals
that were already dead. In this activity, you’ll explore different physical
characteristics of T. rex and compare them to modern predators and
scavengers. Your job will be to piece together the evidence to support
whether Tyrannosaurus rex was a scavenger or predator.
Directions:
Make a hypothesis
I think T. rex was a (circle one)
scavengerpredator
because
Materials:
̻ Pencil
̻ Internet Access
Collect Evidence
#1: Teeth
Tyrannosaurus rex had powerful four-foot long jaws with large teeth, all of a
similar shape and size. The teeth had small serrations but were not extremely
sharp. Based on the size of T. rex’s mouth, scientists estimate it could have
swallowed up to 500 lbs. of flesh in a single gulp. Was it decaying flesh that
T. rex sniffed out, or was it torn from an animal T. rex pursued and attacked?
1
Research the T. rex, wolf and hyena. Describe the jaw size as well as the
shape, angle, and type of teeth found on each one. How do they compare?
Wolf Skull (Predator)
Hyena Skull (Scavenger)
T. Rex Skull
This evidence supports that T. rex was a:
Scavenger
Predator
Both
#2: Eye size, position, and vision
Hunting animals, like tigers or wolves, have eyes that face forward. The viewing
range of each eye overlaps and creates an area of binocular vision. Binocular
vision is what allows us to figure out if something is close to us or farther away,
which is important for hunters targeting prey. Hunting animals, especially hawks
and owls, also tend to have eyes that are very large relative to their head size.
2
Compare how the eyes of each animal below are positioned on their head. What does
that mean for their field of view? Rank each animal according to each characteristic.
field of view
overlap
field of view
overlap
Pig (Scavenger)
Puma (Predator)
field of view
overlap
T. Rex
Eye Position Score
1 = In Front of Head
2 = In Between
Pig
3 = Side of Head
T. Rex
Puma
Eye Size Compared to Head Score
1 = Large Eyes
2 = Medium Eyes
Pig
3 = Small Eyes
T. Rex
Puma
Eye Position Score
1= Large Field of View
2 = Medium Field of View
3 = Small Field of View
Pig
Puma
T. Rex
Pig
Total Score
Puma
Total Score
T. Rex
Total Score
This evidence supports that T. rex was a:
Scavenger
Predator
Both
3
#3: Speed and shape of body used to chase and catch prey
The sheer size of a T. rex suggests that it might have been clumsy when running
down prey, and T. rex arms appear too small to hold its victims! However, new
research has suggested that its arms still might have been useful, and stronger
than they look.
Using the internet to help you, find out how fast each of these animals can run. Then,
describe any adaptations each animal might have for both chasing and catching prey.
Cheetah (Predator)
Jackal (Scavenger)
T-Rex
Speed
Helpful
Adaptations
for Catching
Prey
(Body shape,
Camouflage,
etc)
This evidence supports that T. rex was a:
Scavenger
Predator
Both
4
Putting the Pieces Together
After comparing the T. rex’s physical characteristics with that of modern day
scavengers, review your evidence. Which idea do you think your evidence
supports? Was your hypothesis right?
Challenge Yourself!
A T. rex’s claws were sharp and shaped like a hook, but not great weapons
since its arms were so short they couldn’t touch each other. In order to
understand how a T. rex may have used its claws, it is helpful to study modern animals
that also have claws and try and understand how each animal uses them to survive.
Take a look at the claws from modern day animals. How does each animal use
its claws to survive? How might scientists use this information to help them when
trying to understand adaptations of dinosaurs from the past, like the T. rex?
MODERN
ANIMAL
CLAW
T. rex claw
FUNCTION
How does this animal use its claws to survive?
Bear
Owl
Koala
Cat
5