What Can You Learn From A Dinosaur Track?

The size and shape of a dinosaur footprint gives us some information about the dinosaur.

Look at the footprint on the left above. This is an impressed track (indented into the rock). Notice the toe on the left appears to be attached to the side of the foot. That is one characteristic indicating a theropod dinosaur made this footprint. In addition, the toe that appears to be on the side of the foot is always on the inside of the foot. That means the dinosaur's right foot made this footprint.

Next look at the tip of the center toe. Notice that it bends slightly to the left. For theropods the tip of the center toe tends to bend toward the inside of the foot. That's another indication this is a right foot.

Take a look at the footprint on the right (above). Is this a left or right foot? The tip of the center toe is not bent, but the toe on the right may be attached slightly closer to the heel than the toe on the left. That would indicate this may be a right foot. Yes, this track is harder to read. Dinosaur tracks were made by a living animal who could move its foot and change its stance, and the track was made in a medium (mud in this case) that varies greatly. That means dinosaur tracks are highly variable and their identification may not be clear. It also means this track, which most likely is a theropod right foot, may not be a right foot or even a theropod footprint.

Here's something interesting to do: If you visit a museum that has a theropod dinosaur skeleton with footprints on display, check to see if the footprints are correct for the left and right feet. Often they are not.

Looking At Raised Tracks

In a photograph it can be difficult to know if you are looking at a raised or impressed footprint. The above picture shows a raised track.

Notice the track has big claws. The center toe is long, and the footprint is longer than it is wide. And one toe appears to be attached to the side of the foot. It's a theropod footprint. But, is it a right or left foot?

A raised track is a natural cast of the dinosaur's footprint. That means the foot impression is on the bottom side of the rock. To see that impression we need to turn the rock over. That means what we are seeing here is a footprint for which the right and left sides are swapped. Look at the palm of your left hand. Your thumb is on the left. Now turn your hand over and look at the back of your hand. Your thumb is now on the right. That's what we are seeing when we look at a raised track. It is the opposite of the depressed footprint.

Notice the tip of the center toe and claw bends downward in this photo. And the toe that appears to be attached to the side of the foot is on the bottom of the picture. That means this is a right foot. Do you see it? Remember you are looking at a reversed image (mirror image).

Although this foot impression is very high quality, we've made this one more difficult to see by looking at a raised track turned on it's side. However, all the characteristics of a theropod's right foot are there.

How Big Was This Dinosaur?

To get the approximate size of the dinosaur, measure the footprint from the tip of the center toe claw, to the back of the heel. For this track that is about six inches. This is the dinosaur's foot length.

To get the height of the dinosaur at its hip, multiply the foot length by four. In this example that gives us 24 inches. The dinosaur that made this footprint stood about two feet high at the hip. Please note, this is a rough estimate. The ratio varies from four (used here) to five. It would be equally valid to multiply the six inch foot length by five to get a hip height of 30 inches. That's a variation of six inches, and is as close as we can get.

To get the size of the dinosaur take the number of inches in the foot size and that number is approximately the number of feet from the tip of its nose to the tip of its tail. In this example the foot is six inches, that means the dinosaur is six feet from nose to the end of its tail. Another way to say it (or if you are working in metric), multiply the foot size by 12 to get the size of the dinosaur. Again, this is a rough estimate. Some, instead of multiplying by 12, will multiply by 10. Just like people there is variation in dinosaurs. Some small people have proportionally large feet, and some large people have proportionally smaller feet. What we can say is this dinosaur was probably between five and six feet from nose to tail.

These formula only give an approximation and the ratio can vary with the dinosaur. However, they do give us a rough idea of the size of the dinosaur.

Next - Ornithopod Tracks   Go Deeper - Mud Crack Evidence