What feature on the Gredos Ibex horns allows observers to estimate the animal's age?

Answer

A new ring appearing each year

For the Gredos Ibex subspecies, their horns grow consistently, with a new ring appearing annually, enabling observers to make a rough estimation of the animal's age by counting these rings.

What feature on the Gredos Ibex horns allows observers to estimate the animal's age?
animalMountainmammaladaptationIbex