Last week there was big news for Moab Giants! A team of paleontologists, including our scientists, Dr. Martin Lockley, Dr. Gerard Gierliński and Dawid Surmik described in the journal Scientific Reports http://www.nature.com/articles/srep18952 mysterious traces made by theropod dinosaurs. This amazing discovery came from the 110 million years old rocks in the Gunnison Gorge and Dominguez-Escalante National Conservation Area, in western Colorado, 70 miles (about 100 km) east of Moab. Several large areas with digging or scraping marks indicate dinosaur behavior unlike any reported before. Because of close evolutionary relationships between dinosaurs and birds scientists compare their behavior with living birds. Some bird species show a so-called “nest scrape display” behavior as part of their breeding or mating rituals. This is a type of foreplay, before mating and nest building.

Moab Giants Tracks Museum - Acrocanthosaurus
Moab Giants Tracks Museum

Many modern birds engage in elaborate and very energetic mating behavior rituals. These involve dancing, which includes, wing, tail, leg and neck movements as, for example, in the male peacock tail display. They also involve what is called “nest scrape display” showing a partner “I know how to build a nest!” Today such displays take place in the breeding season (spring), most likely near nesting sites.

Moab Giants Tracks Museum - Theropod Digging Traces
Moab Giants Tracks Museum - Theropod Digging Traces
Moab Giants Tracks Museum - Theropod Digging Traces

Dr. Gerard Gierliński found the well preserved footprint inside one of those digging structures and indentified it as the footprint type called Irenesauripus. Fourteen years ago, Dr. James Farlow from Indiana-Purdue University, studying similar tracks from Texas showed that those types of footprints were made by huge carnivorous dinosaurs – Acrocanthosaurus.

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