Abstract - American Bison Behavior Patterns at Wind Cave National Park

Shult, Milo Jack. 1972. American bison behavior patterns at Wind Cave National Park. PhD Dissertation. Iowa State University. 178 p.


A field study of the behavior patterns of American bison (Bison bison bison) was made at Wind Cave National Park in South Dakota. The study was conducted from June 1, 1968 to Novemeber 17, 1968 and from March 10, 1969 to February 24, 1970, a total fo 17 months. The main emphasis in the study was placed on calving behavior, cow-calf relationships, and rutting behavior. Observations were made throughout the year to provide a basis for comparison with the calving and rutting periods. These behavior patterns are described to enhance the recreational resource value of bison.

A total of 27,583 acres of interspersed grassland and coniferous forest was available to the bison herd. The herd varied in size from 222 animals to over 300 depending on the size of the annual calf crop and the numbers of bison culled during the annual roundups. A total of 3,363 recorded observations were made of bison activities during a total of 2,929 hours in the field. Additional observations were made when detailed field notes were not taken.

Bison were segregated by sex except during the rutting season. Lone bulls and bull groups ranged primarily in the southwestern portion of th park. The bull groups varied in size from 2 to 17 animals and consisted of bulls 4-years old and older. Cow-calf groups ranged primarily in the northern and eastern portions of the park and varied in size from 3 to 240 animals. These groups included cows, calves, and juveniles of both sexes. During the rut lone bulls and members of bull groups entered these groups for courtship and breeding.

Behavior patterns involving grooming, ingestion, elimination, and aggression (agonistic behavior) were described.

Bison cows became wary of human approach prior to the calving season. Because of this, only one incident of parturition was observed. Cow-calf relationships involved a close intimacy during the first week of the calves' lives. This bond decreased in intensity with increasing age in the calves.

Adult bulls investigated cows and formed tending bonds during the rutting periods of June through September for both years. During the peak of the rut chase patterns were recorded. No complete copulations were observed, but indicators of breeding were recorded.

Three interactions between bison and elk (Cervus canadensis) were recorded. These involved harassment of two elk calves and an adult bull elk by the bison. No evidence of predation on bison was recorded. Encounters with humans resulted in varied responses by the bison depending on the degree of harassment.

Examples of the possible effects of bison behavior on the American Indians, particularly those tribes of the Great Plains, are presented in the disseration.

Last updated: April 10, 2015

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