Let’s Talk Bones

Mule Deer Shed Their Velvet In Anticipation Of The Autumn Rut

Story and photos by Reid Neureiter
For the GPHN

Deer antlers — think whitetail, mule deer, moose and elk — are the fastest growing bones in the world. 

According to the U.S. Fish and Wildlife Service, elk and mule deer antlers can grow more than an inch a day during the high growth days of summer. Immature antlers are covered in skin with short, dense fur — they’re called velvet for a reason. 

As seen below, in July and early August, mule deer bucks at the Rocky Mountain Arsenal National Wildlife Refuge north of Park Hill can be seen lounging in bachelor groups, sporting heavy, growing antlers with rounded tips encased in thick brown velvet. The velvet indicates that the antlers are still growing, with an oxygen-rich blood supply bringing calcium to the antlers. They start as cartilage and then calcify into bone.  

The driving force toward large antler growth is good nutrition, and so good habitat is critical for bucks to grow massive antlers.

Come late August and early September, antlers reach their final size, and the velvet dries and becomes itchy. You can sometimes see mule deer bucks rubbing their antlers on tree trunks or branches to remove what is left of the dried, rotting velvet. As seen at bottom right, the antlers become sharp and dangerous spikes, which are used in the battle for breeding dominance.

The velvet is shed in early September, and the mule deer mating season — called the rut— happens in earnest in November and can last into the new year. By February, the antlers will be shed and the growth process will begin anew.