Challenger Monroe’s Field Notes

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Giant Squid

FIELD NOTES
Date: Cretaceous Period
Site: Western Interior Seaway
Subject: Giant Squid
Participants: C. Monroe

Millions of years ago, North America was split in two by a shallow sea known as the Western Interior Seaway. Throughout the Cretaceous Period, this sea was warm, nutrient-rich, and full of life. Sharks, fish, plesiosaurs, and ammonites shared the water with another, more mysterious creature: the giant squid.

Very little is known about the giant squid that lived in the Western Interior Seaway. Unlike fish and ammonites, squid do not have hard bones or shells that easily fossilize. This means that most of a squid’s bulk will rot away before any fossilization can occur. However, two squid body parts are tough enough to enter the fossil record. The first is the squid’s hard, birdlike beak. The second is a spoon-shaped structure known as the gladius, which helps support the mantle, or body, of the squid. Based on these two body parts, scientists have tried to figure out what an ancient squid would have been like.

Because paleontologists have very little evidence to work with, they don’t always agree with each other! Some scientists believe that the ancient squid known as Tusoteuthis might have been up to twenty-five feet long. Others think it was shorter and squatter, perhaps only about eleven feet long. Some paleoartists – artists who draw scenes from the Mesozoic Era – have created pictures that show giant squid fighting with other Cretaceous marine monsters, like mosasaurs. Others point out that there’s no evidence battles like that ever happened!

There is one thing all scientists do agree on: there were squid in the Western Interior Seaway, and they were large. As more fossils are found, who knows what new discoveries they might make?

Marginal comment: The only way to know for sure what the giant squid of the Cretaceous were like would be to go back and take a look at one…

Want to learn more? Check out these sources!
http://www.prehistoric-wildlife.com/species/t/tusoteuthis.html
https://www.wired.com/2012/08/giant-squid-vs-mosasaur/ (content warning: mild language)

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Hadrosaurs

FIELD NOTES
Date: Cretaceous Period
Site: North America
Subject: Hadrosaur
Participants: C. Monroe

Hadrosaurs, commonly known as “duck-billed” dinosaurs, lived on Earth during the late Cretaceous period, 75-65 million years ago. The term Hadrosaur is actually a broad category that contains many species that share common traits, including their distinctive duck-like mouths. Different hadrosaur species could grow to be different sizes. For example, the species sauropholus could be 30 feet long and weigh 2 tons, but the species shantungosaurus could grow to be 50 feet long and weigh 15 tons! That’s almost ten times as large as an elephant!

Because Hadrosaur fossils are often found in large groups, scientists think many Hadrosaur species traveled in herds. Fossils have also been found that show adults standing near eggs, nests, and baby dinosaurs. Based on this evidence, scientists believe that Hadrosaurs looked after and cared for their young. One Hadrosaur species was even given the name maiasaura, or “good mother lizard.”

Some Hadrosaur species had long crests on the backs of their heads. These crests contained passages that connected to the dinosaur’s nasal cavity. Scientists have shown that if air is forced through these passages, the crest can make a loud sound. They believe Hadrosaurs might have used the noises from their crests to communicate with other animals in their herd. 

Hadrosaur fossils have been found all over the world. In fact, so many Hadrosaur fossils have been found that scientists believe Hadrosaurs may have been the most populous dinosaur of the late Cretaceous!

Marginal comment: These “duck-billed” dinosaurs actually had hundreds of teeth. Some species could have up to 1,000!

Want to learn more? Check out these sources!
https://www.fossilera.com/pages/about-hadrosaurs
https://www.thoughtco.com/hadrosaurs-the-duck-billed-dinosaurs-1093749

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Albertosaurus

FIELD NOTES
Date: Cretaceous Period
Site: North America
Subject: Albertosaurus
Participants: C. Monroe

Albertosaurus, known scientifically as Albertosaurus libratus, was a large meat-eating dinosaur that lived at the end of the Cretaceous Period. Fossils of Albertosaurus have been found in the northern part of North America, mostly in Canada, Alaska, Wyoming, and Montana.

Albertosaurus was a large theropod that was closely related to Tyrannosaurus rex, and looks like a slightly smaller version of its famous cousin. It had a large, strong skull that contained 80 curved teeth. It was about 9 meters (30 feet) long, and could weigh up to 1,500 kilograms (3,300 pounds)!

Scientists have been trying to discover if Albertosaurus was a hunter, or a scavenger. Its forward-facing eyes probably gave it good depth perception, and it likely also had a great sense of smell. Both of those qualities would help make it an excellent hunter. Some scientists even believe that Albertosaurus hunted in packs! 

Most scientists currently believe that Albertosaurus used both hunting and scavenging to get food. They would hunt dinosaurs like Hadrosaurs, the duck-billed dinosaurs, but also scavenge from a carcass if they happened to find one. Using both strategies would help them find enough food to support their huge bodies.

Like its cousin T. rex, Albertosaurus had very short arms that ended in two-fingered hands. Most people might think these little arms were useless, but scientists aren’t so sure! They’ve found heavy scarring on Albertosaurus arms that suggest they were using their arms for something. Scientists just have to figure out what!

Marginal comment: I wouldn’t want to run into one of these in the middle of a dark forest!

Want to learn more? Check out these sources!
https://www.sdnhm.org/exhibitions/fossil-mysteries/fossil-field-guide-a-z/albertosaurus/
https://www.nhm.ac.uk/discover/dino-directory/albertosaurus.html

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Western Interior Seaway

FIELD NOTES
Date: Cretaceous Period
Site: North America
Subject: The Western Interior Seaway
Participants: C. Monroe

In the Cretaceous Period, North America looked very different from what we know today. The middle of the continent was covered by a shallow sea that connected the Gulf of Mexico in the south to the Arctic Ocean in the north. This means that states like Colorado, Wyoming, Nebraska, and Kansas used to be entirely underwater! Scientists call this sea the Western Interior Seaway, or the North American Inland Sea. 

The sea was formed when the Rocky Mountains began to rise. The motion that caused the mountains to rise also caused land east of the mountains to dip. Because the planet was very warm at the time, there was no ice at the poles and sea levels were much higher. The high water flowed into the dip and split North America in two.

Because the sea was so shallow – only about 2,500 feet deep – it was very warm and full of life. The bottom of the sea contained little oxygen, which means that animals who died there were easily fossilized. Scientists have found fossils of huge marine reptiles like plesiosaurs and mosasaurs, as well as giant bony fish, huge clams, and turtles the size of cars! They have also found evidence of cartilaginous animals, like giant sharks, which are not normally fossilized. Some of the most spectacular fossil finds in the world have been found in the area that was once covered by the Western Interior Seaway. 

What happened to the Western Interior Seaway? At the end of the Cretaceous Period, Earth underwent sudden cooling, likely due to the same massive asteroid strike that ended the time of the dinosaurs. As water began to freeze at the poles, sea levels fell. Eventually, the Western Interior Seaway dried completely, leaving the flat, dry land we know today.

Marginal comment: Scientists have also found evidence of giant squid in the Western Interior Seaway.

Want to learn more? Check out these sources!
https://www.realclearscience.com/blog/2019/10/26/what_lived_in_north_americas_ancient_inland_sea.html
https://www.cretaceousatlas.org/geology/

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Troodon

FIELD NOTES
Date: 74-65 million years ago
Site: Earth
Subject: Troodon
Participants: C. Monroe

Troodons, known scientifically as Troodon formosus, were small theropod dinosaurs who lived near the end of the Cretaceous period. Theropods are dinosaurs who walked on two legs and ate meat. Scientists today believe that some theropods are the evolutionary ancestors of modern birds.

The word “Troodon” means “wounding tooth,” and this dinosaur certainly earned the name! Its teeth are long, pointed, and have saw-like serrations along the edges. Paleontologists believe that these serrations may have been used to help chew plant matter, and may be a sign that Troodons were omnivores – animals that eat both meat and plants.

Troodons are very interesting dinosaurs. They have large brains for their size, and scientists believe they may have been one of the smartest dinosaurs. They lived together in social groups, and scientists believe they brooded over their eggs. This could make them an important link between early egg-laying crocodilians and modern birds!

Troodons were less than one meter tall and between two and three meters long, though some large teeth found in Alaska show that some Troodons may have been larger. Fossils of Troodons have been found in North America and in northeastern Asia.

Marginal comment: Scientists believe Troodons were intelligent, for dinosaurs. They don’t know the half of it…

Want to learn more? Check out these sources!
https://www.nhm.ac.uk/discover/dino-directory/troodon.html
https://www.nationalgeographic.com/animals/prehistoric/troodon-formosus/

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Geologic Time

FIELD NOTES

Date: 4.5 billion years ago, to present
Site: Earth
Subject: Geologic Time
Participants: C. Monroe

Earth is a little over 4.5 billion years old. Over all those years, Earth has changed a lot. The weather, atmosphere, and land have all changed many times. Many creatures that used to roam the Earth no longer exist today. For a long time, there was no life on Earth at all!

When scientists study Earth’s past, they use something called “geologic time.” Geologic time splits Earth’s history into sections. Think about how we split the lifespan of a human into sections: baby, child, teenager, adult. Scientists do the same thing for the lifespan of the Earth.

The biggest sections are called “eons.” There have only been four eons so far. The first eon began when the Earth formed. Our current eon – the Phanerozoic Eon – began more than 500 million years ago.

Because eons are so long, scientists break them down into smaller sections called “eras.” Then they break the eras into even smaller parts called “periods.” When a scientist says that something happened during a certain period, everybody knows exactly what part of Earth’s history they are talking about. They know what kinds of plants, animals, rocks, and atmosphere existed on Earth at that time, and how long ago it was.

Today, we live in the Quaternary Period, which is part of the Cenozoic Era. The era right before ours was the Mesozoic Era. That was the time of the dinosaurs. Dinosaurs went extinct about 65 million years ago, which feels like a long time to us. In terms of geologic time, however, it’s like it happened only yesterday.

The Mesozoic Era is split into three periods: Triassic, Jurassic, and Cretaceous. Different dinosaurs existed during each period. At the end of the Cretaceous, a huge natural disaster caused the dinosaurs to go extinct and ended the Mesozoic Era. The time of the dinosaurs was over; the time of mammals was just beginning.

Marginal comment: The Triassic, Jurassic, and Cretaceous Periods all have interesting dinosaurs. However, I find the population at the end of the Cretaceous to be the most fascinating.

Want to learn more? Check out these sources!
https://geology.com/time.htm
https://sciencing.com/three-time-periods-dinosaurs-lived-8737410.html

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The History of the Universe

FIELD NOTES
Date: time=0 to 2020 AD
Site: the Universe
Subject: Natural History
Participants: C. Monroe

The Universe began with a bang. About 13.7 billion years ago, all of the matter in the universe exploded into existence in a single tremendous burst of energy. A few hundred million years later, the first stars had formed. And many billions of years after that, the first planets.

Our planet, Earth, was formed roughly 4.6 billion years ago. A wide disk of gas and rock was orbiting around a newly-formed star. Today, we call that star the Sun. Over time, bits of those rocks began to stick together, to form larger and larger bodies in space. Eventually those bodies became planets. One of those planets was our Earth.

At the beginning of its life, Earth was a violent place. Volcanoes blasted from the surface and asteroids fell from the sky. Some of the asteroids that hit Earth contained water. When they smashed into the ground, the water was thrown into the sky as a vapor, or gas. As the Earth cooled, this water vapor condensed and fell to the ground as rain. Even as the first oceans began to form, however, lava still flowed. Earth experienced near-constant volcanic eruptions for almost 700 million years.

As the planet cooled and oceans formed, life on Earth began. No one knows exactly how. But somehow, deep within those primordial oceans, matter came together to form one-celled organisms that could absorb energy and reproduce. And from those single cells, the whole great train of evolution began rolling.

That’s when things really got interesting.

Marginal comment: 13.7 billion years. Compared to that, even my great travels have covered only the blink of an eye in the history of the Universe.

Want to learn more? Check out these sources!
https://www.nasa.gov/mission_pages/spitzer/multimedia/timeline-2006121889912.html
https://thewire.in/science/a-brief-history-of-the-earth-how-it-all-began