Bison are iconic North American animals. Many wonder about their distinct features, especially how horns differ between sexes, which helps distinguish males from females.
Horns on Female Bison
Female bison, also known as cows, possess horns, a permanent feature that remains throughout their lives and does not shed like antlers. These horns are composed of keratin, the same material found in human fingernails. Female bison horns generally appear thinner and tend to curve inward towards their heads. They typically grow up to two feet long. Calves are born with small horns that continue to grow and change shape as they mature.
Differences in Horns and Their Purpose
While both male and female bison have horns, noticeable differences exist in their size, thickness, and curvature. Male bison, or bulls, typically have horns that are heavier, thicker at the base, and less curved than those of females. As bulls age, their horns tend to stand more upright, while a cow’s horns will curve inward and backward.
Horns serve multiple purposes for both sexes. They are primarily used for defense against predators such as wolves, bears, and mountain lions, allowing bison to charge, slash, and gore threats. During the breeding season, bulls use their horns to establish dominance and compete for mating rights, engaging in powerful displays of strength. Bison also utilize their horns for foraging, especially in winter, to clear snow and ice to access vegetation.
Other Ways to Distinguish Bison Sexes
Beyond horn characteristics, several other physical traits can help differentiate male and female bison. Males are significantly larger and heavier than females, with adult bulls weighing up to 2,000 pounds and standing around six feet tall at the hump. Females, in contrast, typically weigh about 800 to 1,200 pounds and stand around five feet tall.
Bulls also exhibit a more pronounced muscular build, particularly in their head, neck, and shoulder hump. Their heads are often described as massive and block-like, covered with a thick, curly mop of hair, while a cow’s head is narrower and more linear. The shoulder hump, which consists of muscle and elongated vertebrae, is notably larger and more developed in males. While both sexes possess a beard, it tends to be more prominent in bulls.