Flagstaff, AZ – Every year bull elk spend a lot of energy growing and hefting around antlers. These phenomenal structures, made purely of bone, have been known to grow at a rate of 1 inch per day during summer.
But is it worth it? Growing bony headgear that quickly requires enormous amounts of calcium. Some of it comes from plants, but most of it is provided by the bull elk's own rib bones. Only the healthiest of males can afford this diversion of minerals from their bodies so a big rack indicates an animal in good shape.
The drama of extracting minerals from bone and hoisting up to 12 pounds of d cor culminates in the rut, or the annual fall mating season. The elk with the largest rack generally gets to mate with the most females.
He also often gets to avoid the energy-expending sparring matches in which lesser bulls engage. His impressive size is a clear broadcast for any contenders to step off, and he can often sit back and let potential mates come to him.
Rocky Mountain elk wear their antlers all winter, slogging through snow to feed on the exposed twigs of mountain shrubs. Even after the rut is over antlers serve a further purpose, as bulls with the most magnificent racks can claim the best winter forage.
This nutritional advantage outweighs the cost of carrying the extra weight. Finally, in early spring, the bulls lay down their spectacular burden and gorge on green growth and then start the process all over again.