Day 4: The Swan Song of the Dinosaurs

Map of Continents Through Time

Time in History: 75.5 million years ago (Cretaceous Period)

Environment Parameters & Graphs of Carbon & Oxygen

  • Habitat: Subtropical Jungle
  • Temperature: 110 Fahrenheit, 43 Celsius.
  • Water: Very wet, humid, 1.8 meters (71 inches) of rain per year.
  • Sunlight: Bright
  • Oxygen levels: 14% lower than today. Breathing at sea level then would be the same as being at 4,000 feet today.
  • C02 levels: 1800 ppm (4.6 times 2012 level of 394 ppm)

Question of the Day:

How were dinosaurs able to grow to such gigantic sizes?

Key Concepts


The lineup at dinnertime stretched past the washbasin, around the back of the expedition trailer, and down a sandy track to our fleet of outfits (those are trucks, for the uninitiated). Each person in the line is an expedition team member with a unique set of expertise. We have paleontologists, cooks, drivers, doctors, cowboys, and of course the runners leading the way, spooning corn and chili on boiled potatoes at the front of the line. It is fitting that we’re on land once dominated by another species in the midst of its most diverse era. At 75 million years old, the rock the runners crossed today represents an era when dinosaurs were their most prolific. They stood as tall as two-storey homes, ate meals that would feed most of the expedition team, and were present in such variety that when our ambassadors dug through this earth at the end of their run, they found fossils of 20 unique species in an area the size of a tennis court. But, there will be no desert for the dinosaurs. Their Swan Song ends tomorrow, when we visit rock that tells the tale of the great extinction that wiped out most of their species.

Daily Video Expert Video

Photos of the Day

Coming Soon!

Character of the Day: Parasaurolophus

Parasaurolophus is a huge plant-eating dinosaur that was common 75.5 million years ago in what became Southern Utah. It is estimated that it grew to 9.5 m (31 ft.) in length, and 2.5 tonnes in weight. Parasaurolophus is known for the long crest that protrudes from the rear of the head.

Youth Ambassador Activity

At the end of the run on Day 4 the Youth Ambassadors will visit the famous Kaiparowits Formation and analyze fossil remains found in a single site to try and reconstruct a Cretaceous ecosystem. They will learn how a complex fossil site is analyzed and the data used to reconstruct the environment. A general overview of the Late Cretaceous and the rapid adaptation that was occurring in terrestrial ecosystems will also be reviewed so the Youth Ambassadors can gain an understanding of the importance of this time period to our modern era.