DETERMINING THE DIET OF ANCIENT ANIMALS
David J. Davies
Department of Geology and Geography
Centenary College of Louisiana
Shreveport, LA 71104
Level: Upper elementary to senior high
Anticipated Learning Outcomes
- Students will explain the relationship between the shape
of a tooth or toe bone and the animal's diet. (Meat-eater, herbivore, etc.)
- Students will predict the overall size and shape of a
dinosaur based on a single bone. (Is it large and bulky? Slim and fast?)
- Students will understand the methodology of functional
morphology, the study of why organisms have the shape they do. (Why does
this animal have a tooth shaped like this? What type of food could best
be cut by this shape of tooth?)
- Students will interpret whether these animals were well
adapted to their environment (e.g., "Survival of the Fittest").
(Is this the best possible shaped tooth/toe to help capture and eat a particular
type of food? Does its predicted diet match with the known shape of the
animal? How could the animal have been better shaped to obtain its type
- Students will be introduced to basic concepts and methods
of paleobiology, such as paleoecology and evolution.
- Replicas of several dinosaur, ichthyosaur or mosasaur
teeth and tooth batteries. (A tooth battery is a group of similarly shaped
teeth that fit together in the jaw; each tooth would act like a single
tooth in a saw blade.) At least one should be from each category: carnivorous
dinosaur; uplands herbivore; lowlands herbivore; ichthyosaur or mosasaur.
- For related activity: replicas of several dinosaur toe
bones; at least one each from a carnivore, an herbivore, and a swimming
ichthyosaur or mosasaur.
Inexpensive, life-like models of dinosaur teeth, toe bones
and other bones may be purchased from Dino Productions (P.O. Box 3004,
Englewood, CO 80155-3004; (303) 741-1587) among other sources. They also
include descriptions of the animals, a drawing of the tooth/bone for student
handouts, and information on their life habits. They can assist you in
determining the feeding habits of the animals whose "bones" you
- Pointed knife
- Fish gig (a stick with hooked, sharpened end to stab
and hold fish)
- Saw blade
- Coarse sandpaper
- Imitation models of dinosaur food
- Paper reproduction of herbivorous dinosaur
- Paper reproduction of fish
- Woody, leafy tree branch
- Soft vegetation: moss, fern, grass, etc.
- Photographic reconstructions of the life activities of
the animals, available in library books on dinosaurs. Good examples are
in the two volume set by the Natural History Museum of Los Angeles County,
- Explain to the class the concept of "Functional
Morphology" (Dodd and Stanton, 1990; Raup and Stanley, 1971); that
is, animals have the shape they do because of their lifestyle. For example,
the reason that predatory sharks have such a shape is they must be streamlined
to catch prey. Birds, in order to fly, must have lightweight but strong,
long wing bones. The same principle, popularly described as "function
defines form", is also true for individual parts of the body; each
part has a shape well adapted to its purpose. For example, since teeth
are used to grasp and cut food, the tooth's shape must be effective in
catching and chewing the type of food that the animal eats. Paleontologists
determine the best model from the real world to use as an analogy for the
body part. For example, the best machine to cut wood is a saw. Therefore,
you would expect the jaw of an animal that eats hard, woody plants to have
a battery of teeth in it that could cut like a saw.
- Then explain that dinosaurs and other large Mesozoic
(Age of Reptiles, 245 to 65 million years ago) animals interacted with
each other and their environment; the study of how organisms interacted
with other species is called paleosynecology. All of these animals ate
one of four types of food: meat (eaten by carnivores); fishes (piscivores);
woody land vegetation (uplands herbivores); or soft swamp vegetation (bottomlands
herbivores). Each must be processed differently to gain the maximum food
value in digestion:
- Meat is easily digested and very nutritious; the prey,
usually other dinosaurs, must be caught and cut into chunks to be swallowed.
- Fishes are also easily digested and very nutritious;
however, slippery fishes are hard to grasp and swallow, typically whole.
- Woody plants, typically living in uplands areas, have
tough leaves and stems; they are thus difficult to eat; the high cellulose
content also makes them the most difficult food to digest. They must be
cut/crushed into very small pieces to be swallowed and digested.
- Swampy plants are typically softer (less cellulose) and
easier to digest than woody plants; however, as they also contain much
less nutritional value, vast quantities must be eaten and ground up, along
with the mud in which they live, so the animal can gain enough nourishment.
- Then demonstrate these four types of dinosaur feeding
patterns by using the tooth models to grasp and process the imitation models
of the appropriate food as a dinosaur would. For example, use the saw to
cut up the small leafy branch, as an herbivore would have used its battery
of teeth to cut up ancient uplands plants. Examples are listed below.
|| Food Processor
|| Piercing, slashing, and cutting teeth
|| Pointed knife|
|| Pointed teeth curved toward the back of the mouth to grasp
and hold slippery prey
|| Fish gig|
| Uplands (woody) vegetation
|| Battery of short, sharp, serrated cutting teeth
|| Saw blade|
| Swampy (soft) vegetation
|| Battery of short, flat teeth for grinding soft food
|| Coarse sandpaper|
- Groups of 3-4 students will then describe teeth from
several different feeding types (guilds) of dinosaurs. Have the group discuss
each tooth to determine: (a) the animal's diet; (b) the likely shape of
each animal. These shapes may include bulky lowlands herbivore (hadrosaur);
trim and fast running carnivore (Tyrannosaurus); water dwelling
piscivore (ichthyosaur); uplands herbivore with long neck to reach tree
tops (Apatosaurus or Diplodocus).
Results, Discussion, Conclusions
- Student groups, after working together, will determine
from a single tooth the likely food source and overall body shape for each
animal. They will write their responses in the table provided, and orally
present their results to the class.
- Results will be checked by the teacher. Class discussion
will then be initiated by naming the animal whose tooth was described,
then showing color pictures of reconstructions of the dinosaur, its habitat
and environment from library books on dinosaurs. Other aspects of its activities,
e.g., family life, solitary or herd lifestyle, cold vs. warm blooded, and
the techniques scientists use to determine these, can then be discussed
to initiate further investigation into paleobiology.
- Discussion will follow centered on how each dinosaur
was able to develop teeth so well suited to its particular lifestyle; this
will lead to the students discovering the concept of adaptation and "survival
of the fittest."
- This exercise allows dinosaurs, kid's favorite fossils,
to be used to introduce basic topics of paleobiology such as predator/prey
interactions; scientific methods of determining lifestyles of extinct animals;
and processes of evolution.
A similar procedure to determine food source, animal body
shape, weight and speed can be developed using toe or claw bones (bones
used to obtain the food cut up by the teeth in the previous exercise). Are
the toes light-weight, with slashing claw attachments as would come from
a fast running carnivore (lion or Tyrannosaurus or Velociraptor);
blocky to support much weight, like a bulky, heavy herbivore (elephant or
Triceratops; or part of a paddle, as a swimming ichthyosaur would
DODD, J. Robert, and STANTON, R.J., Jr., 1990, Paleoecology:
Concepts and Applications: Second Edition, John Wiley and Sons, 497 p.
Natural History Museum of Los Angeles County, 1987, Dinosaurs Past and Present:
v. 1 and 2, University of Washington Press.
RAUP, David M., and STANLEY, Steven M., 1971, Principles of Paleontology:
W.H. Freeman, 481 p.
WHAT DID THAT ANCIENT ANIMAL EAT?