In every culture, in every era, humans have always been fascinated by monsters. We love to sit around the fire- or listen to the radio, or read a book, or play a video game- immersing ourselves in tales of dragons, gorgons, yokai, trolls, asuras, tokoloshe, and even stranger beings that lurk in the unseen corners of our world. The phenomena of cryptids is just the newest iteration of this fascination, though our modern age has added a scientific veneer onto these hidden monsters.
With that being said, I wanted to expand this list of state cryptids out beyond the European American legends to include mysterious beasts form other cultures of the North American continent.
Thunder beings and their rivals, the horned water serpents, are prominent in the legends of many Native American peoples, and are known under many names. Among the Lakota Sioux and other Native peoples of the American prairies, the Thunder Beings are known as Wakinyan, and the horned serpents called Unktehi. The Wakinyan often manifest as great birds to do battle with the serpents, smiting them with lightning and driving them into the Earth. Some legends say that the bones of both combatants can be found all over the American West, particularly in the prairies of Midwest and in the Badlands of South Dakota.
These bones are said to have great wakan, spiritual power similar to the Algonquian concept of manitou. People sometimes gather bones from Unktehi for medicine bundles. And there are stories of evil sorcerers using shards of horned serpent bones to “sting” or curse others.
In the late 1800s, European-American paleontologists such as Othniel Charles Marsh and Edward Drinker Cope came to the West in search of fossils. Guided by Native stories, they collected many of the monstrous bones and identified those of the Wakinyan as pterosaurs. Unktehi bones found on the grasslands were discovered to be from aquatic reptilian mosasaurs, while the bones from in badlands belonged to extinct mammals.
Why, one must wonder though, are the bones of marine animals found in the middle of the prairies? The answer lies in the late Cretaceous period when a long, shallow Interior Sea ran through North America, dividing the continent into the landmasses of Laurentia in the West, and Appalachia in the East. Mosasaurs, ichthyosaurs, and giant carnivorous fish such as Xiphactinus hunted these waters, while pterosaurs soured above the waves, and dinosaurs such as Tyrannosaurus and duck-billed hadrosaurs roamed the shores. Over millions of years, plate tectonics pushed up the floor of the Interior sea, leaving the bones of its prehistoric inhabitants entombed on dry land.
It's important to note that the cryptid commonly called a "Thunderbird" by many European Americans is distinct from the Wakinyan. While the former was definitely inspired by the legends of Native peoples, it tends to be thought of as a natural- if unusual- animal such as a giant bird or even a pterosaur. The Wakinyan, however, is a spiritual being that can take many forms. I've talked about the other type of Thunderbird- and an imfamous phantom photograph of one that everyone remembers, but no one can find- in a previous post.
SOURCES
Fossil Legends of the First Americans by Adrienne Mayor
Lakota Belief and Ritual by James R. Walker, edited by Raymond J. DeMallie and Elain A. Jahner
A legend of the Unktehi from the National Park Service website
Information on the "horned serpent" from Native-Language.org