YELLOWSTONE NATIONAL PARK — Yellowstone National Park (YNP) shared on Sunday, Dec. 1, that bighorn sheep complete an altitudinal migration in late fall and early winter, versus a latitudinal migration over hundreds or thousands of miles north and south.
Snow in the mountains means that bighorns will become more visible as they migrate down to lower elevations in the Greater Yellowstone Ecosystem.
“Moving down in elevation has brought them to places easier to observe than their summer haunts high in the mountains,” YNP said via Facebook.
The completion of bighorn migration corresponds with their rut or mating season in November and December, YNP said on Facebook. Mature rams will rear up on hind legs and crash their heads together to establish dominance during mating.
YNP confirms that ram skulls have two layers of bone above the brain that function as a shock absorber. This bone adaptation helps to protect a ram’s head during the collision of head-on fighting.
“If you’re really lucky you might not only see those majestic rams but you might witness their epic head-butting battles!” YNP wrote on Facebook.
A ram’s horns will continue to grow its entire lifetime. A female’s horns will grow very little after four to five years, likely due to reproductive efforts says the National Park Service (NPS).
“This time of year is perfect to observe a full-curl ram sporting an entire lifetime’s worth of horn growth,” YNP said.
According to the NPS, the horn size of bighorn sheep rams will influence dominance, rank and the entire social dynamics within the herd.
