Horns and antlers are both typically used for defending territory, fighting off predators and attracting mates. Many people use the terms horns and antlers interchangeably, but they refer to two very different structures. So how do we tell them apart?
Antlers are a characteristic of the family Cervidae that helps us to recognize its members, including deer, elk, moose and caribou. Only male members of this family possess antlers, except for caribou-where both males and females develop antlers. Antlers can be forked or branched, with the physical size and appearance changing between species. Typically, the size of antlers reflects the age and strength of the male, which appeals to potential mates. Antlers are shed and regrown annually, growing larger every year. Growing antlers annually uses up a large amount of an animal's energy, so a male with large antlers is more impressive to females because he has the strength to grow a large rack.
Antlers are made of bone and develop from pedicels, bony structures that are fused to the skull that help to support the antlers as they grow. New antlers are covered with velvet to carry blood and nutrients to the antlers as they are developing. When the antlers are done growing the velvet dies and is shed as the animal scrapes its antlers on brush and trees. This also helps to stain, shine and sharpen the rack to appear more impressive to potential mates and when competing with other males. In the winter, the hormones that helped to grow and maintain the antlers are no longer produced, so the pedicel loses calcium, weakening the connection between the antlers and pedicel until the antlers are shed.
Horns are found on members of the Bovidae family, including bison, bighorn sheep, and mountain goats. They can grow on both males and females depending on the species, and also vary widely in size and shape. Unlike antlers, horns are single protrusions, and are never branched, forked or shed. Horns start to grow shortly after birth and continue to grow nonstop throughout an animal’s life as they are worn down through use over time. A horned animal will always have its horns unless they are broken off.
Horns are comprised of an internal living bone core which is covered with a permanent sheath of keratin-which makes up our hair and fingernails. The boney core is fused to the skull with connective tissue but is not a part of the skull.
Pronghorns are found in southern Alberta and possess unique horns. They are branched near the base and have a hook near the tip. Pronghorn horns do consist of a boney core and keratinous sheath, but the sheath is shed annually unlike the permeant sheath held by Bovids.