Coyotes are so common in South Dakota that the University of South Dakota athletic teams are the “Coyotes.” The coyote was made the official state animal in 1949.
 
South Dakota became a state in 1889, but “Coyote State” was used before that. “Coyote state” (both Dakotas) was cited in print in 1877, 1883 and in early 1889. “‘Coyote State’ meaning the State of South Dakota, of course” was cited in an 1893 newspaper.
 
South Dakota’s official nickname is “The Mount Rushmore State.”
 
     
University of South Dakota
USD QUICK FACTS
Location: Vermillion, S.D.
Founded: 1862
Enrollment: 10,061
Nickname: Coyotes (KI-Yotes)
 
Chronicling America
1 May 1877, Daily Press and Dakotaian (Yankton, SD), pg. 1, cols. 3-4:
THEY ALL WANT IT.
More Arguments in Favor of the State of Dakota.
The Vermillion Standard.
(...)
Let us hope that in the near future we shall have a place assigned us among the states that have preceded us in Uncle Sam’s fold, and that the star of the Coyote state will yet shine brightly from our country’s flag.
 
1 February 1883, Dakota Daily Leader (Huron, SD), pg. 4, col. 3:
Buffalo Poem.
NOT BY A NEW YORK MAN.
(...)
We’ll have the ‘‘coyote state,”
The “dug-out” state, also.
Where roamed the Indian wild,
Where roamed the buffalo.
 
Chronicling America
25 April 1889, Jamestown (ND) Weekly Alert, pg. 4, col. 3:
The Kansas press points with pride to its idol, calls her a typical Kansas girl, and now from across the coyote state comes a warning note, Let the Dakota girl Beware!
 
12 March 1890, The Daily Boomerang (Laramie, WY), “Extracted from Exchanges,” pg. 2, col. 2:
Wind River Mountaineer: “Equality state” and “Geyser state” have been suggested as nicknames for Wyoming. Why not call it “Coyote state” or as an innovation drop the state and call it “Old Maid’s paradise?”
   
31 January 1893, Aberdeen (SD) Daily News, “A Vigorous Protest,” pg. 2, col. 2:
EDITOR NEWS:—I recently received through the mail a pamphlet, the backside of which was adorned with the portrait of the sender, and the front page with these words: “Coyote State Almanac.” “Coyote State” meaning the State of South Dakota, of course.
 
Google Books
A History of the United States for Schools
By John Fiske and Frank Alpine Hill
Boston, MA: Houghton, Mifflin and Company
1895
Pg. 516:
The state of North Dakota is sometimes called the Sioux State, while its southern sister has been called the Coyote State.
 
Google Books
The WPA Guide to South Dakota
Compiled and written by the Federal Writers’ Project of the Works Progress Administration
Pierre, SD: State Publishing Company
1938
Pg. ?:
Animal Life: The coyote is a native of South Dakota, and is the State university mascot and the State animal. At one time South Dakota was known as “the Coyote State.” These animals are still quite numerous in western South Dakota, where it has been estimated by professional hunters that there is an average of one coyote to each square mile.
 
OCLC WorldCat record
Poets of the coyote state : an anthology of verse by residents of the state of South Dakota.
Publisher: [S.l.] : Paebar Co., ©1948.
Edition/Format:   Print book : Poetry : English
Database: WorldCat
Summary:
Includes poems by Mrs. Earl Arne, Ruth Thomas Burns, A’lise Churchill Chaphe, Badger Clark, Mary A. Fink, Edwin C. Graber, Corinne Huntington Jackson, Gladys Mackey, Mary Frances Martin, Mildred Irwin Peterson, Velma Rickenbach, Sister M. Eunice, Ardelle Tellinghuisen, Edna Tystad, Lerna Diez Veling, Esther L. Voller, Rachel A. Walradth, Edna Weaver, Fannie B. Williams.
 
OCLC WorldCat record
North Dakota the flickertail state, South Dakota the coyote state
Author: H.M. Gousha Company.; Continental Oil Company.
Publisher: Chicago : H.M. Gousha Co., ©1959.
Edition/Format:   Map : English
 
OCLC WorldCat record
Early stories of the coyote state.
Author: Chloe Garber
Publisher: New York : Vantage Press, 1973.
Edition/Format:   Print book : English
 
OCLC WorldCat record
South Dakota crime in perspective : crime in the “Coyote State.”
Author: Morgan Quitno Corporation.
Publisher: Lawrence, Kan. : Morgan Quitno Corp., 1994-
Edition/Format:   Journal, magazine : English
 
Google Books
Focus on American English & Culture
By Pierfranca Forchini
Milan: EDUCatt - Ente per il diritto allo studio universitario dell’Università Cattolica
2014
Pg. 52:
South Dakota
(...)
The other common nickname is The Coyote State, which comes from the prairie wolf, named by the Nahuatl Indians as the “coyotl”, from which we get “Coyote” (and which is also a nickname for the residents of the state).