90,000 Miles to Me

16,478 Miles • Mrs. T-Rex

Heading east from Yellowstone National Park, I wound a circuitous route through several high mountain passes in gorgeous northern Wyoming.

Circuitous mountain passes. All of the roads in this picture are one continuous road. It was like this for many, many miles. The white patches are snow. In August.


Circuitous…and beautiful. Another of these picturesque lakes is at the top of this page.

This nimble climber was scampering up rocks overlooking a sign that read “Beartooth Pass Summit Elevation 10,947.” At this elevation, some areas had the same characteristics as the Arctic tundra.

The pass behind me, I turned north and back west, eventually coming to Bozeman, Montana, where Zephram Cochrane built and flew the Phoenix, the first starship from Earth to achieve faster than light speeds using warp drive. His first flight attracted the attention of a Vulcan scout ship and led to Earth’s first (confirmed and acknowledged) contact with extra-terrestrials in 2063, ushering in a new era of peace and prosperity for humanity.

Unfortunately, the memorial of this event, including Cochrane’s statue, won’t be built for another hundred years, so I didn’t get to see that on this trip.

Instead, I took a trip through time in the other direction, courtesy of the Museum of the Rockies. Montana is a treasure trove of dinosaur bones, and one find in particular grabbed my attention.

In 2000, a field crew digging for dinos in a corner of northeastern Montana called the Hell Creek Formation, struck gold with an unprecedented five T. Rex specimens in one summer. One of those was poking out of the middle of a 40 foot cliff, miles from the nearest unpaved backroad. After more than three weeks of labor-intensive digging, hammering, and shoveling while suspended from the cliff in climbing gear just to get to the the skeleton, and more weeks of digging to carefully remove it, they had unearthed both hind legs and some foot bones. Although the skeleton was incomplete, they were some of the best preserved T. Rex bones ever found.

The T-Rex, whose dig site was nicknamed B-rex, was half way up the vertical face of the rock on the left side of this photo.

At the end of the summer, they packed the bones into a plaster jacket for transport. With no roads nearby, Windway Corporation from Wisconsin sent a helicopter to airlift the package, but at a hefty 3,000 pounds, it weighed too much to lift.
I imagine that at this point there was a lot of hand wringing, head scratching and debating about what to do. It must have been a particularly sticky situation, because paleontologists regularly have to transport heavy fossilized bones from remote locations, and what they chose to do this time is not what scientists usually do with their hard won treasures.

They cut open the plaster jacket and broke their specimen.

A 3.5 foot long femur, to be precise. It could then be safely airlifted out. Yet in the process of breaking the femur, the fossilized bone shed some fragments, which the crew wrapped up and shipped to a colleague in North Carolina, leading to one of the most remarkable discoveries in paleontology.

Across the country in North Carolina, Dr. Mary Schweitzer, a biologist with a strong background in paleontology–an unusual combination–found medullary bone inside that well preserved and broken femur. She ran numerous tests and conclusively confirmed that this was indeed medullary bone. 

Medullary bone is a highly specialized type of tissue that is only formed in the marrow cavities of adult female birds just before laying eggs as a way for the body to store extra calcium that will then be used to form the eggs. Based on the amount of medullary bone present, this T-Rex probably died during egg-laying. 

Dinosaurs had two active oviducts, so they laid two eggs a day (birds today have one oviduct and lay one egg a day) and from the remains of egg nests, we know that most dinosaurs laid between 12 and 30 eggs, so egg-laying would have taken from 6 to 15 days. If Mrs. T-Rex had died after egg laying, there wouldn’t be any medullary tissue left. If she died before egg-laying, more of the tissue would be expected.  

This is the first time that any dinosaur remains have been conclusively identified as either male or female. Scientists have been trying for ages to differentiate between males and females by the shape or size of their body, size of their head crest, ornamentation, anything. None of those seem to have been much different between males and females. They even tried looking for indications of sex via behavior. The closest they ever got was one dino who was found sitting on two eggs. But nothing had been conclusive until this.

Dr. Schweitzer continued testing the samples, using methods common in biology but never tried in paleontology, where the assumptions are that fossils are bones turned to stone with no biological traces left to be found. Her unusual techniques paid off, however, and in 2005 she dissolved the bone fragments in dilute acid to remove some calcium phosphate. When the rock wore away, what remained was soft tissue–the matrix part of bone that consists primarily of collagen. She has since found blood vessels, cells, proteins, and other soft tissues. 

Schweitzer compared her samples to those of ostrich and emu, the biologically most primitive living avian relatives to dinosaurs.

The prevailing wisdom is that soft tissue is not supposed to be able to last very long, and certainly shouldn’t be preserved for thousands or millions of years. But she indeed found, and it has been confirmed, in multiple dinosaur samples, that soft tissue can and does remain in these 65 million year old fossils.

This discovery is forcing scientists to reconsider how fossils are formed. How could soft tissue be preserved, and what can we learn from it? When she first published, headlines over-dramatized the finding, touting it as the first step to dinosaur cloning and Jurassic Park-type theme parks. Schweitzer insists that they are a long, long, long, way off from that. They haven’t even found DNA yet, and it would probably be badly damaged even if they did. 

For me, I think what they did discover is fascinating enough. Just think, that blood vessels and cells have survived, encased in what is essentially stone, for 65 million years, not breathing or eating, not alive, but not entirely decomposed, either. For me, this shows me one more glimpse of how wondrous and complex and fascinating life is, and how little we understand about the mysteries of the universe. 

And it is all because some desperate paleontologists were willing to take a chance and do the unthinkable, they broke their bone, and gave some fragments to an unorthodox colleague who tried some unusual tests and got surprising results. I love stories with a happy ending. 


*Photos with the beige background were taken from displays at the Museum of the Rockies

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