Q. When deer lose their antlers each year, do they grow back in the same pattern?

A. Yes, the new pattern is remarkably similar — at least until old age, when malnutrition may interfere.

The process of antler regeneration and the chemical signals involved are incompletely understood. The antlers are used for sexual display and fighting, and sex hormones play a key role, especially in the timing. Light signals from the changing day length are also involved.

The close replication from year to year strongly indicates a genetic component, according to the leading researcher on antlers, Richard H. Goss, the author of “Deer Antlers: Regeneration, Function and Evolution.”

The annual loss and swift regrowth of antlers in the buck deer is one of the most intriguing phenomena in the mammalian world, and some experts think that studying it may shed light on the possibility of regenerating human organs.