The difference between antlers and horns is that antlers are shed each year and are made of bone while horns are kept for life and are made of living tissue and bone with a sheath that is very similar to human finger nails.
Antlers vs. Horns: The Bone vs. Keratin Showdown
If you've ever confused a moose with a buffalo or a deer with a goat, you're not alone. But here's the thing: those impressive head decorations follow completely different biological playbooks.
Antlers are pure bone—solid calcium and minerals that deer, elk, and moose grow fresh every single year. They sprout in spring, mature by fall, then drop off in winter like nature's most dramatic fashion cycle. During growth, they're covered in fuzzy skin called velvet that supplies blood and nutrients. Once mature, that velvet dries up and gets scraped off, revealing the hard bone underneath.
Horns, on the other hand, are permanent residents. Animals like sheep, goats, and cattle grow them once and keep them for life. The structure is a bony core covered by a sheath made of keratin—yes, the same stuff as your fingernails and hair. They're not solid bone all the way through, which makes them lighter but still incredibly strong.
The Annual Antler Miracle
Antlers rank among the fastest-growing tissues in the entire animal kingdom. A bull elk can add an inch of antler per day during peak growth. That's insane when you consider they're growing entire pounds of bone in just a few months. The energy cost is massive, which is why only well-fed, healthy males can pull off the biggest racks.
After breeding season wraps up, antlers become dead weight—literally. The connection weakens, and they fall off. Come spring, the whole process starts over. Some animals grow larger antlers each year as they mature, while injury or poor nutrition can result in smaller or deformed growth.
Horns: Low Maintenance, High Durability
Horn-bearing animals skip the drama entirely. Their horns keep growing throughout life, though the rate slows as they age. The keratin sheath gets worn down through fighting and environmental contact, but it's constantly being replaced from the base. Think of it like a nail that never stops growing.
Because horns are permanent, they're built differently. They're often curved or spiraled for structural strength and combat effectiveness. Bighorn sheep can have horns weighing 30 pounds—about 10% of their total body weight. These aren't just for show; they're weapons honed over millions of years of head-bashing evolution.
The Pronghorn Exception
Here's where biology gets weird. The pronghorn—that speedster of the American West—breaks all the rules. It has horns made of keratin sheaths over bone cores, but it sheds and regrows the sheaths annually like antlers. It's the only animal on Earth that does this, making it a biological oddball that scientists find endlessly fascinating.
Why the Split?
The antler-horn divide comes down to evolutionary strategy. Deer family members (cervids) evolved antlers as seasonal breeding signals—big antlers mean good genes and plenty of food access. Horned animals (bovids) went for permanent weapons that also serve as year-round status symbols and defense tools.
Both strategies work brilliantly in their respective niches, which is why you'll find antlered animals across North America, Europe, and Asia, while horned species dominate Africa, Asia, and mountainous regions worldwide.