JACKSON, Wyo. — It’s antler growing season for moose and other members of the deer family like mule deer, elk and white-tailed deer in the Greater Yellowstone Ecosystem.
For bull elk, antler growth begins soon after they shed their previous set, in March and April. The first set of antlers begins growing for bull elk at about one year old. According to Yellowstone National Park (YNP), antler growth is triggered in spring by a combination of two factors: a depression of testosterone levels and lengthening daylight.
The antler-growing period is shortest for yearling bulls, about 90 days, and longest for healthy, mature bulls, about 140 days. Roughly 70% of the antler growth takes place in the last half of the growing period. Antlers of a mature bull will grow two-thirds of an inch each day. The antlers of a typical, healthy bull are 55–60 inches long, just under six feet wide, and weigh about 30 pounds per pair.
Unlike moose, bull elk retain their antlers throughout the winter. Bulls use their antlers to settle disputes and bulls with larger antlers are at the top of the social structure, garnering them better feeding sites and attracting the best mates.
For elk, moose and other members of the deer family, growing antlers are covered with a thick fuzz, referred to as velvet. According to YNP, the velvet is actually skin and a network of veins. Blood flowing in the skin deposits calcium that makes the antler. Usually around early August, further hormonal changes signal the end of antler growth, and the bull begins scraping the velvet off, polishing and sharpening the antlers in the process.
Moose
Moose antlers grow from April or May until August, says YNP. Beginning as small bumps called pedicles on each side of the forehead, the antlers enlarge until they are knobs. The knobs change into antlers and grow until August.
Yearlings grow six- to eight-inch forked antlers; prime adult bulls usually grow the largest antlers—as wide as five feet from tip to tip.
Bulls usually shed their antlers in late December to late January, although young bulls may retain their antlers as late as March. Shedding their heavy antlers helps moose conserve energy and promotes easier winter survival, according to YNP.
In the summer, an adult moose consumes as much as 50 pounds of food per day.
Bulls weigh close to 1,000 pounds while cows weigh up to 900 pounds. In the summer months, moose blend in well to their environment and can be surprisingly hard to see for such large animals. They are likely to stand their ground even when they hear people approaching, so pay close attention to your surroundings, especially in prime moose habitats such as willow thickets or around streams or ponds.
Unlike bears, it is okay to run from moose, says the National Park Service. The Park Service offers the following safety tips.
- If it hasn’t detected you yet, keep it that way
- If it knows you’re there, talk to it softly and move away slowly
- Don’t be aggressive – you want to convince the moose that you aren’t a threat
- If you think the moose is going to charge you, take cover or run away
Although moose and elk have “eye shine” or tapetum lucidum underneath the retina of their eyes, they can be hard to spot at night because they stand higher than headlights and have dark coats. Drivers are urged to slow down and be mindful of wildlife, especially at dawn and dusk.
