Bison Bellows: Vocalization

About Bison Bellows:

In November 2016, the National Park Service Biological Resources Division in Fort Collins, Colorado, began the 52-week long "Bison Bellows" series. Every week, "Bison Bellows" featured short articles—known as "Bellows"—highlighting stories centered on three themes: meeting the herd, meeting the people, and telling the story. In essence, it is a celebration of all things bison.

NPS Photo.

What sound does a bison make? The answer may not come to you as fast as "moo" for a cow or "baa" for a sheep, but that is because bison make a variety of sounds. These sounds include anything from the low rumblings of male bellows heard during mating season to the high-pitched bleats of a calf looking for its mom. Other common sounds consist of "snorts," "coughs," "roars," and "grunts."

During mating season, known as the rut, male "bellows" are commonly heard. These bellows have been compared as to revving up an old Chevy truck! It is believed that these bellows announce the male's presence and establish dominance within the herd. The frequency of these sounds increase during male-male competitions or when they are trying to find mates. Scientific studies indicate that the acoustic qualities such as the frequency, length, and volume of the bellows demonstrate which males are more dominant, and therefore, a better mate to females. These vocalizations may reveal information about the male's competitive ability, physiological quality and condition, and sexual receptivity---in other words, the bellows denote fitness-related information.

Calves also produce a variety of sounds such as higher pitches grunts and bleats. These vocalizations are commonly associated with when they are searching for their mothers or when they are playing with other calves. As calves grow older, they will not stay as close to their mothers and when calves have traveled too far, their mother will utter a series of low-pitched grunts and the calf will respond with higher-pitched ones. So next time you find yourself in a national park or wildlife refuge, tune into listening for the classic sounds of bison!

Check out the Yellowstone National Park sound library for some of the common bison sounds - including a bellow - you'll hear in national parks!

Read more Bison Bellows here.

Did you know?

Mature bull bellows can be heard up to three miles away during peak rutting season!