BACKGROUND:
Paleontologists recognize two basic categories of fossils: body fossils
and trace fossils. Body fossils are pieces or impressions of an ancient
plant or animal. Bones, leaves, feathers, eggs, scales, and shells are all
body fossils. From these we can learn about the physical appearance of the
fossil organism. Trace fossils are remnants of the activities of
ancient animals. Examples of trace fossils include nests, burrows, trails,
footprint track ways, coprolites (fossil dung), and gastroliths (stomach
stones). Trace fossils yield unique information about behavior that is not
revealed by body fossils.
Study of dinosaur footprints and track ways has contributed significantly
to our understanding of dinosaur behavior. From track way sites we have
learned that some types of dinosaurs traveled in herds, that some herds
protected their young by keeping them in the centers of migrating groups,
and that dinosaurs did not drag their tails when they walked (reptiles drag
their tails). Paleontologists can also estimate dinosaur gait and speed from
some footprint track ways. They can even identify specific behaviors such as
hunting, fleeing, or protecting young from others.
All children have seen footprints and tracks, but they may not realize
how much you can learn from them. In this postlab exercise, the students
will try to use their knowledge from the previous lab to interpret tracks.
PROCEDURE:
- Students have now looked at footprints and footprint patterns. This
activity reviews their results from the previous two activities.
Ask the students what type of footprint patterns they observed when
they made footprints during the lab. First, go over the pattern made if
the dinosaur was walking. Have one or two students come to the board and
draw this walking pattern. Do the same for a walking 2-legged dinosaur
with a tail and 4 legged dinosaur running. The correct patterns are
shown below. You wish to demonstrate this with your students by actually
walking or running. Remember a four legged animal walking and a four
legged animal running are very different. If your students have trouble
visualizing the patterns, use some analogies a cat or a dog walking and
then running.
- Have students suggest types of information about dinosaurs (or any
animal) we could get from studying footprints, based on their experience
making tracks outside. Put a list of the things that they suggest on the
board. Your list might include: size of the animal, weight of the
animal, number of feet the animal walked on, age of the animal, or
number of animals traveling together.
- Have the students examine the tracks labeled A, B, and C in their
worksheet. They are on the following page in this manual. Explain that
these are drawings of real dinosaur tracks. Based on the shape and
pattern of the tracks and track ways have students answer the following
questions:
- Which tracks were made by a dinosaur with large claws? (Track way
C)
- Which tracks were made by a dinosaur that walked on four legs?
(Track way A)
- Which tracks show a mother and youngster walking together? (Track
way B)
