When Sharks Swam the Great Plains

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If you’ve ever been to, or lived in, or even flown over the central swath of North America, then you’ve seen the remnants of what was a uniquely fascinating environment. Scientists call it the Western Interior Seaway, and at its greatest extent, it ran from the Caribbean Sea to the Canadian Arctic.

Thanks to Dmitry Bogdanov, Nobu Tamura, C.R. Scotese, NASA and the many others listed throughout the video for making their images available to use.

Produced for PBS Digital Studios.

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References:
Oceans of Kansas: A Natural History of the Western Interior Seaway (Second Edition) by Michael J. Everhart.

[TK]

Another thing people tend to forget, the Seaway at its deepest was maybe 400 ft (122m) deep. For contrast the Mediterranean is up to 17, 000+ ft (5, 200 m) deep in places. Meaning the Seaway was incredibly shallow, that meant these predators were literally stacked on top of each other in the water column. But this also meant that the Seaway was one of most abundant and plentiful water ways of all time, which is really how it supported all those predators.

[moxxym]

More ancient marine biology please, its so cool

[veo_]

I love how genuinely excited she seems when discussing how a xiphactinus died after eating something too big for it's entire digestive system.

[Justaguy]

When I was younger, fossil hunting was a big hobby of mine. I'm from Minnesota, and all the fossils I found were shells or other sea dwellers. Even found a Cephalopod, whose shell was in excess of 5 feet, in a stone quarry.

[vegavega]

I have a mountain farm in Norway, (A farmstead located on a mountain), and while building on the farm we had to dig out foundation for a new building-- Underneath the ground we found alot, and I mean-- ALOT of sea shells and sand, which shows that even this mountain has been submerged at some point in time.

[mitchellskene]

No matter what, I'll always call the Western interior Seaway "Hell's Aquarium"

[johngrill]

Hey, can you do a story on the different periods of the Sahara when it becomes a grassland filled with lakes etc

[johannelbekian]

When I read the title, I imagined sharks on two legs running through the Great Plains. Thank you for this beautiful thought.

[nothisispatrick]

Shark: How would anyone eat the likes of us?


Humans: Are you being rhetorical or asking about recipes?

[katiemould]

This woman’s voice always makes my problems go away.. so relaxing :p

[ajedogawa]

"Beasts that found ways to thrive even in spite of each other.." how poetic and philosophical! Love this channel

[Laura-vvyu]

I would like to see an episode on the evolution of modern fish. Like when and how did saltwater and freshwater fish split and adaptations to different water conditions like pH, hardness, and temperature.

[thejimmydanly]

Fascinating video! I'm from the Texas Panhandle, near Palo Duro Canyon, a steep sided canyon (very similar geographically to the Grand Canyon, in fact, it's the second largest in North America and often called the Grand Canyon of Texas). One very interesting feature of the canyon is that, due to many of the historical layers being revealed, you can actually find the layer from when this sea existed (you can visually identify it because of the slightly green color). If you are lucky when hiking in this layer, you can actually find shark teeth! I highly recommend visiting if you're ever travelling through this part of Texas. It's only about 20 minutes south from Amarillo. (Oh, and one thing we have over the Grand Canyon is that you can drive down into the canyon!)

[alienworm]

It always seems like the topic follows the new ecology/paleontology term being taught, and I love it
"Let's make a video explaining niche partitioning, and we'll use this super neat example as a backdrop"

[FathermanQ]

I could only imagine that, not only did some of the smaller fish and marine reptiles migrate from the Arctic to the Caribbean (and vice versa) for purpose of spawning or simply more suitable temperatures, but that their predators would lay in wait at specific locations that would either bottleneck their prey or simply be advantageous due to the currents of the waterway. Big eyes in marine animals today generally occur in the nocturnal species as well, so perhaps (even though living at the same time) some predators merely hunted at different times of the day. Squid are more active at night than in the daytime. I love this channel! Thank you all for your hard work and wonderful information to get the world thinking. Best thing on the internet, right here 👏👍👍

[couchpotatoe]

2:54 "Now North America was a land divided by two!"
Hard to imagine these days, right? xD

[Uncultured_American]

HOW HAVE I NEVER HEARD OF A FRIGGING OCEAN RUNNING THROUGH WHAT IS NOW THE US?? If there was ever anything that that proves how much our high schools suck, it’s this. Thank you PBS for teaching me and others on YouTube about the Earth’s amazing history!

[nump]

I am very curious about ancient life in the Amazon. How long was the Amazon covered in rain forest? What environments existed before it became the world's largest rain forest? Are there other regions that had bigger or comparable rain forests, and how did those jungles disappear?

[planetpeterson]

Videos every week, and not just awesome content but content that I would have NEVER thought of. So glad this channel exists, nothing else like it.

[NavyDood]

I love all the episodes of Eons. I would love to see you and the team you work with produce a long, Planet Earth, style documentary.