Reindeer are the only deer where both the males and females grow antlers. Male antlers can reach up to 100 centimetres (39 inches) in width and 135 centimetres (53 inches) in beam length, while females’ are usually smaller at around 50 centimetres
(20 inches) long. Used for rutting, defending territories and protecting food, antlers require a lot of energy to grow. Males grow their antlers in March to August, while females grow theirs from June to September. The antlers are shed after the mating season and grow back larger each year. Antlers start growing at around two years old and are initially sparklike until the age of three years, where they begin to branch off.