Antlers!

White-tailed Deer at Hagerman NWR, by Larry Paar

Majestic moose. Elegant elk. Regal deer. What makes them so memorable? Antlers! National wildlife refuges are home to thousands of antlered animals. Here are some fascinating facts about antlers. 

Bull moose at Seedskadee National Wildlife Refuge in Wyoming. (Photo by Tom Koerner/USFWS)

Fact #1: Adult male elk, caribou, moose, white-tailed deer and mule deer – all native to North America -- have antlers. Most female caribou have antlers, too.  They all belong to the Cervidae family of mammals.

Fact #2: North America has four subspecies of elk: Roosevelt, Rocky Mountain, Tule and Manitoban.  Roosevelt elk, the largest subspecies, are found in the Northwest, including at: Willapa and Julia Butler Hansen Refuges in Washington and Nestucca Bay, William L. Finley and Bandon Marsh Refuges in Oregon.  Tule elk live in California, including at San Luis and Bitter Creek Refuges. Caribou (also known as reindeer) are found at many of Alaska’s 16 national wildlife refuges.  

Fact #3: Antlers can grow up to an inch per day, among the fastest-growing animal tissue on the planet. 

Fact #4:  Antlers are made of bone.  All antlered animals have a velvet phase, which helps antler growth by providing a blood supply to the growing bone. Before breeding season, the velvet dries up and the animal rubs the velvet off on vegetation. 

Tule elk in velvet at California’s San Luis National Wildlife Refuge. (Photo: Steve Martarano/USFWS)

Fact #5: Antlers serve various purposes. They facilitate competition among males for females. They are also used for defense against predators. They can also be used to assert dominance – usually for food and against others in the same species. 

Fact #6: Size matters. Antler size is an indication of male health because antlers take a lot of resources to produce and carry. Only healthy males can produce the largest antlers. Elk antlers can grow to seven or eight points each, can have a length and spread of four feet and can weigh 20 pounds each.

Fact #7: During the annual rut (breeding season), males use antlers to display dominance. Females tend to mate with males that have the largest antlers. Sometimes a male will carry vegetation on his antlers. Biologists believe the male is trying to enhance his size. For elk, moose and caribou, the rut generally occurs in late summer/early fall. For deer, it’s generally November/December.

Fact #8: After the rut, elk, moose, caribou and deer shed their antlers. The pedicles – the bony protrusions from which the antlers grow – often are injured. Once they are healed, a new set of antlers typically begin to grow.  

Fact #9: Although a new set of antlers grow each year, an animal doesn’t necessarily grow antlers of similar form each year.

Fact #10: Antlers are not horns. The deer (Cervidae) family has antlers. Bison, antelopes, sheep, goats and domestic cattle – all in the bovine family – have horns. Antlers are composed of bone. Horns are composed of keratin (same material as hair and fingernails) on the outer portion and live bone on the inner core. 

Bighorn sheep have horns, not antlers. This photo is from the National Bison Range in Montana. (Photo: Dave Fitzpatrick/USFWS volunteer)

Antlers! is from the Friends Newswire, a service of  US Fish & Wildlife