Dinosaur Trackway Analysis Objectives: 1. To apply the procedures used to analyze dinosaur track ways 2. To examine dinosaur tracks to determine speed of movement Introduction The study of dinosaur tracks is yielding considerable information regarding the behavior of dinosaurs. To date, thousands of dinosaur track way sites have been found, and their examination has produced information that has changed the way we think of dinosaurs. Early in this century, dinosaurs were thought of as slow moving plodding animals. But in the last three decades, the detailed study of dinosaur trackways has changed our view of dinosaur behavior to one of rapid moving intelligent animals capable of parental care and coordinated hunting behavior. Procedure: This laboratory will use the details described during the presentations. Don t let the math confuse you. You will be able to calculate dinosaur speeds by simply plugging in the values into the various formulae. First, you need to know the leg length of the dinosaur. Generally the leg length is estimated from the length of the footprint. The footprint is 20% the length of the leg, or you can find the leg length by taking the footprint length times 5. The leg length is 5 times the length of the track. Next we need to measure the length of the stride, which is the length between two consecutive left or right prints.
The stride is measured from the same point on two consecutive right or left prints Next you must determine your relative stride using the formula: Relative stride = length of stride / Leg length Because larger animals can run faster than smaller animals, we must take that into account. To solve that dilemma we need to determine the dimensionless speed. Experiments on mammals determined a relationship that relates the length of the relative stride with dimensionless speed, which can be used in a formula to calculate dimensionless speed. The relationship between relative stride and the dimensionless speed is found with the formula: dimensionless speed = (relative stride -.72) / 1.19 Once the dimensionless speed of a dinosaur has been found, calculating the actual speed is easy using the formula: Actual speed = dimensionless speed times the square root of the (leg length x gravitational acceleration) The gravitation acceleration is 10 meters/second 2. Therefore the Actual speed = dimensionless speed times the square root of the (leg length x 10 meters/second 2 ) Example: First you must measure the various components of the trackway. If a single track is 0.5 meters long, then the length of the leg should be Leg length = track length x 5
or Leg length = 0.5 m x 5 = 2.5 m. Next you need to find the relative stride. If our example has a stride length of 6.5 m, then the relative stride would be: Relative stride = 6.5 m / 2.5 m = 2.6 Now you must determine the dimensionless speed of the dinosaur using the above formula Dimensionless speed = relative stride -.72 / 1.19 = (2.6 -.72) / 1.19 = 1.58 Therefore the actual speed would be Actual speed = 1.58 x square root of (2.5 m x 10 m per sec 2 ) = 7.9 m per second The conversion to km/hr would require that we do the following conversion. 7.9 m/sec x 3.6 km/hr = 28.44 km/hr. There are 1.6 km per mile thus to find the dinosaurs speed in mph, divide 28.44 by 1.6. The dinosaur was running at 17.78 mph! That dinosaur was moving. At Glen Rose, Texas there is a famous trackway site that will provide a case study for us. The area has a large number of tracks, but we will use one set. The footprint is approximately 0.51 m long. It is pictured below.
The trackway can be easily measured using a tape measure. The stride was 6.5 meters. The length of the pace (the distance between consecutive right and left prints) is shown below. Calculate the leg length, relative stride, dimensionless speed and actual speed of the following five dinosaur examples. Using the data from the images above of a single track being 0.51 meters long and the stride being 6.5 meters in length. Calculate the speed at which the dinosaur was moving. Use the table to see how the calculations are preformed. Trackway problem sets 1. A T rex with a track of 0.64 m long was found to have a stride of 9 meters. Calculate the speed of the dinosaur. 2. If the T rex was found to have a stride of 3 meters, then how fast was it moving? 3. A trackway showed a dinosaur with a track of 0.2 meters long and a stride of 5 meters. How fast was this dinosaur moving? 4. The Oxford Megalosaurus trackway had tracks that were 0.64 m long. The stride of the tracks was 2.5 m long. How fast was that dinosaur moving?
5. Tracks further along the trackway had a stride length of 4.6 m. At what speed was this dinosaur moving at that point? 6. A Cetiosaurus trackway had a track size of 0.6 m and a stride length of 2.8 m. How fast was it moving? Dinosaur Trackway worksheet To calculate the dinosaurs speed simply fill in the track size (T) and Stride length (L) from the above data, and complete the calculations indicated. You will end up with the speed in mph. The sample trackway from the introduction is included for your reference. If you are proficient in Excel, you can set up a spread sheet that will simply do the calculations for you. Make sure you format the numbers for only two significant digits track T leg length L stride S relative stride R dimen. speed D actual speed m/sec A km/hr K T T x 5 S S/ L (R-.72)/ 1.19 D x (L x 10) A X 3.6 K/1.6 mph 0.5 2.5 6.5 2.6 1.58 7.9 28.44 17.78
Identifying dinosaur tracks is quite easy. Theropod tracks have three slender toes that often show evidence of a claw. Ornithopod tracks are also three toed, but they are not as pointed and have a more rounded heel. Sauropod hind tracks are rounder with a fore track that is half the size. Examples of each of these and others were presented in lecture. Below is a photograph of a large set of dinosaur tracks. Draw lines along the tracks that were likely made by the same individual (hint the tracks seem to be moving along the same path). Try to identify the types of dinosaurs represented, and how many individuals were present?
Questions: 1. In trackway one, the leg length of the Tyrannosaurus was A. 2 m B. 3 m C. 3.2 m D. 4 m E. 6 m 2. In trackway one, the relative stride of the Tyrannosaurus was A. 2.1 m B. 2.6 m C. 3.2 m D. 4.3 m E. 6.7 m 3. In trackway two, the speed of the Tyrannosaurus with a stride of 9 m in mph was A. 12.5 B. 29.1 C. 22.38 D. 31.2 E. 44.2 4. In trackway three, the relative stride of the dinosaur was A. 2.5 m B. 2.9 m C. 3.6 m D. 5 m E. 6.4 m 5. In trackway three, the speed in mph of the dinosaur was A. 25.59 B. 12.9 C. 30.6 D. 16.5 E. 6.4 5. In trackway four, the speed in mph of the Megalosaurus was A. 2 B. 3.4 C. 1.1 D. 0.66 E. 2.8 6. In trackway five, the speed in mph of the Megalosaurus was A. 2.33
B. 7.67 C. 9.22 D. 5.32 E. 4.54 7. In trackway six, the speed in mph of the Cetiosaurus was A. 2.21 B. 3.43 C. 2.77 D. 5.32 E. 7.43 8. Of the six trackway analyzed, which dinosaur was the fastest? A. Trackway 1 B. Trackway 2 C. Trackway 3 D. Trackway 5 E. Trackway 6 9. In the mixed trackway photograph, were there any theropods? A. yes B. no 10. In the mixed trackway photograph, were there any onithopods? A. yes B. no 11. In the mixed trackway photograph, were there any sauropods? A. yes B. no 12. In the mixed trackway photograph, what type of dinosaur was the most common? (hint: this the number of trails you found) A. theropods B. ornithopods C. sauropods D. ceratopsia E. stegosauria