Bison bison (Linnaeus)



Description:   The Bison is the only native member of its family in Kansas. It can be distinguished by: 1) head, lower shoulders and legs dark brown to almost black while its distinctive upper shoulder hump and back are a lighter yellowish brown, and 2) black, curved horns, which may measure (maximum) 970 mm on the outside curve with a 380 mm circumference at the base, and tip to horn spread as wide as 380 mm.

Size:   Adults may attain the following dimension: total length 1980-3800 mm; tail 430-815 mm; hind foot 460-660 mm; ear 110-150 mm; weigh 410-910 kilograms. Adult females are approximately 40 percent smaller than adult males.

Range and Habitat:

A Bison bull (shedding Winter coat).
Photo by Alice P. Munzo.   Copyright 2000. All rights reserved.

   In the early 1800's the Bison was the dominant large mammal occupying the prairies of North America, with a population numbering in the millions. Bison once occurred statewide in Kansas, with the larger herds located on the central and western prairie. The Flint Hills and the drainage area of Smoky Hill River supported herds numbering in the hundreds of thousands. Herds grazing across the rolling hills covered the prairie from horizon to horizon. One herd alone in southwestern Kansas was estimated to contain over four million bison. This was in 1871. By 1879 the Bison was reported exterminated in Kansas when the last known survivor was killed west of Dodge City. Today a few small herds are maintained on reservations in the state.

   The rut of Bison is prolonged, with male activity from early July to late September. During this time the bulls engage in butting and shoving matches to establish dominance and access to receptive cows. Breeding is somewhat more restricted in time, and, after a gestation period of approximately nine to nine and a half months, a single calf (rarely twins) is born in late April or May, rarely June. The young calf lacks the characteristic hump and is tawny to yellowish in color. Calves are very precocious, and able to follow their mothers a few hours after birth. Within a few weeks the coat darkens and the hump begins to develop. By autumn the calves are nearly as dark as adults. They remain with the females throughout their first winter. Growth continues into the seventh or eighth year. Cows first breed at two to three years of age, but bulls usually do not attain breeding size until they are four or five years old.

A pregnant bison cow.
Photo by David M. Watson.   Copyright 1999. All rights reserved.

Habits:   Bison were highly gregarious, living together in large herds. Bison inhabiting the woodlands of eastern Kansas lived in smaller groups. The core of the herd was formed by the cows, accompanied by calves, yearlings, and two-year olds. Older bulls stayed on the periphery of the main herd, in small bands or alone, except during the rut, when they joined the cow-subadult bands within the main herd. They usually sought water twice a days, although they could go for several days without watering during periods of drought. Old bulls were sometimes solitary. In spring and summer while shedding thick winter wooly hair, bison wallowed in depressions, moist or dry. The dust or caked mud may have afforded some relief from parasites, flies, and mosquitoes. Even today these basinlike depressions can be found in Kansas, formed by the thousands of wallowing bison who carried away the mud in their shaggy coats. Isolated rocks and trees were also used as traditional rubbing spots. Bison herds on the Great Plains migrated seasonally, north in summer and south in winter. Unfortunately, their migratory habits were never carefully studied, and we remain ignorant of the details.

Food:   The Bison was a very efficient grazer of prairie grasses and plants, more so than domesticated cows. It consumed a wide variety of both grasses and broad leafed plants.

Remarks:   Bison (sometimes called buffalo) herds encountered by early Kansas settlers were viewed with dismay. They were incompatible with the homestead style of agriculture practiced at that time. Commercial meat hunters and robe collectors, and the ever increasing number of human settlers soon reduced the hundreds of thousands of Kansas Bison to a few scattered individuals. From 1868 to 1881 2.5 million dollars was paid to in Kansas for Bison bones gathered on the prairie, and one man in Dodge City (after 1873) shipped over 3,000 railcars of Bison bones to carbon works about the country. The normal maximum life span of Bison was 20 to 30 years.,

Return to the Mammals of Kansas index page.