Cow elk sometimes have tiny outgrowths on their skulls in the same location you find pedicles on bull elk. Renowned elk biologist Valerius Geist calls them “mini-pedicles.” One reason may be ovarian cysts in older females that can cause high levels of androgen, which can induce pedicle growth. And while it’s rare, cows can even sport short spikes that remain always in velvet, sometimes referred to as eo-antlers. Testosterone imbalances, trauma or disease can all cause such antler growth in cows.
But evolution might also be the culprit behind antlered cows, Geist says. Over time, cow elk in North America have evolved to compete with young bulls for resources by developing male traits, a process called male mimicry. It’s girl power, Darwin-style.
Caribou might be the best example of male mimicry at work. Females exert a lot of energy digging through snow to reach buried lichens. Young bulls will try to steal this forage by displacing females. Through male mimicry, female caribou have evolved to have similar body size and small antlers to help level the playing field with these young bulls.
Unlike their diminutive red deer cousins, cow elk rival young bulls in body mass and grow a similar large neck mane. “What we see in female elk is that there is a potential for the female to grow antlers as young males and females stay together,” says Geist. “She is on the way to becoming more male-like.”
Have you ever seen a cow elk with antlers? Let us know below.