Emory Report

September 25, 2000

 Volume 53, No.5

Martin uses Apache methods to track dino-behavior

By Keely Solomon

How did dinosaurs behave? The question has puzzled scientists for more than 150 years. Paleontologists can reconstruct what dinosaurs looked like; geologists can determine the physical nature of the environment that they lived in.

Behavior, on the other hand, is a characteristic exhibited by living animals, and reconstructing the behavior of creatures extinct for 65 million years can be quite challenging.

Anthony Martin, however, is undaunted. A senior lecturer in environmental studies, Martin has recently taken a novel approach to interpreting ancient animal behavior.

Martin is an ichnologist; he studies plant and animal traces, or "biogenic structures." These traces include any feature made by a living plant or animal, such as tracks, burrows, nests and feces, and they are often preserved in the fossil record. Because they are the result of the activity of a living organism, traces are a valuable resource for understanding animal behavior, both modern and ancient.

Traditionally, an ichnologist studies an animal trackway by describing the shape and size of the footprints and measuring the distance between them. The researcher can then use these data to determine the type of animal that made the tracks and the speed at which it was moving.

According to Martin, much more can be learned from animal tracks than simply the identity and gait of the animal. "To me, that's very unimaginative," he said. "That's acting like [the animal] is a robot. These tracks represent the dynamic movement of a living animal, and it comes alive by looking at those steps."

In an attempt to extract more information from animal tracks and trails, Martin has added a new twist to ichnology: He has begun using Apache tracking methods to study fossilized footprints. According to Martin, these methods allow the researcher to make many interpretations-gender, handedness, head direction, subtle pace changes, weight-that cannot be made using traditional ichnological tracking techniques.

Martin learned much of the Apache tracking methodology through two courses taught by Tom Brown Jr., founder of the Tracker School. Brown, author of 16 books on wilderness skills, is purported to have learned his tracking skills from an 83-year-old Lipan Apache scout beginning when he was 7.

The tracking techniques are based on the identification and interpretation of certain pressure-induced points left within the track. Brown refers to these subtleties as "pressure release."

"The pressure release features are giving you details and nuances of behavior that you ordinarily would not get from what most ichnologists see," Martin said.

Head position provides a good example of how this technique works. If a standing person looks up, they have more weight on their heels. If they look down, the weight becomes shifted to their toes. "So you can look at the depth of the track with regards to the toes versus the heel to tell this sort of head position," Martin explained.

Martin presented his novel application of this old technique in August at the International Geological Congress meeting in Rio de Janeiro, Brazil. "It's something that does provoke incredulity," he said.

Obviously, Martin can never actually observe the behavior of the extinct animals that made the fossilized tracks. Therefore, validating the behavioral interpretations made from the footprints will present a special difficulty. However, Martin said the accuracy of this methodology can easily be tested using modern animals.

For example, a video camera can record an animal's movements, and then a scientist can use the Apache methods to interpret the tracks made by those movements. The validity of the scientist's interpretations can then be checked against the videotape. "You can genuinely, empirically test it," Martin said. "That's the real potential I see in this."

To further test his methodology, Martin plans to study fossilized tracks from a wide range of animals, both vertebrate and invertebrate.

Shorebirds are one group of animals he plans to study. These birds have existed for 90 million years, and many have left fossilized tracks as old as some of the dinosaur tracks he studies. Unlike dinosaurs, however, ancient shorebirds had very similar anatomies to their living relatives, whose behavior can be observed.

In addition, Martin plans to study mammal tracks recorded in the more recent fossil record and test how their behavior may have differed from their modern descendants.

Though he is currently one of the only academic ichnologists to employ these Apache techniques to the study of fossilized tracks, Martin hopes that will soon change. "I see this as completely scientific," he said. "I'm encouraging people to test it."

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