Horns vs. Antlers

Bighorn sheep, as the name implies, grown horns.

NPS

Horns never shed and continue to grow throughout an animal's life. Antlers are shed and regrown yearly. One exception is the pronghorn, which sheds and regrows its horn sheath each year.

Horns

• Found on pronghorn, bighorn sheep, and bison
• Are a two-part structure. An interior portion of bone (an extension of the skull) is covered by an exterior sheath grown by specialized hair follicles call keratin (similar to human fingernails).
• Horns are usually found on both males and (in a diminutive form) females.
• Generally permanent; horns continue to grow throughout the animal's life and are not shed.

Elk antlers can grow an astonishing 1 inch per day and generally grow larger on older males.

NPS / Jacob W. Frank

Antlers

• Found on members of the deer family—grow as an extension of the animal’s skull.
• Made entirely of bone and are a single structure.
• Generally, are found only on males.
• Grow and are shed seasonally; most species grow a new set of antlers every year.
• Covered in a soft, velvety skin during growth, which provides nutrients and blood supply. Once fully developed, the velvet is shed, revealing the hard bone beneath.

Purpose

Both horns and antlers serve similar purposes, such as:

• Defense against predators.
• Combat during mating seasons to establish dominance and attract mates.
• Display to signal health and vitality to potential mates.