The Differences Between Horns And Antlers – Feathered Photography

Many people use the words “antlers” and “horns” interchangeably as if they’re the same thing. They aren’t.

Occasionally I rerun a favorite older blog post. I was inspired to rerun this one, originally published nearly seven years ago, by a conversation I heard fairly recently on Antelope Island when a car pulled up behind me. Two middle-aged couples got out of the car and I could hear them discussing a small group of nearby Mule Deer. They were trying to determine if the deer were bucks or does and I could hear them repeatedly referring to buck deer as having “horns”.

The teacher in me wanted to gently correct them. I didn’t but resisting wasn’t easy. Today’s post will scratch that itch.

For this version of the post I’ve modified the title, added a photo, edited the text and tweaked the formatting.

Antlers are found on members of the deer family (Cervidae) – all species of deer, moose and elk. This mule deer buck with his neck swollen for the rut has a handsome rack of antlers, not horns. To me his face looks sheep-ish, but that’s neither here nor there.

Antlers:

• are made of bone and found only on males (with the exception of caribou where females have small antlers)
• are grown every spring and shed every winter (with very few exceptions including a couple of small tropical deer species that don’t shed their antlers)
• are typically branched

This is a bull elk whose still-growing antlers are covered in velvet which carries blood and nutrients to the growing antlers. When the antlers reach full size the velvet dies and is shed, leaving the mature antlers behind.

Horned mammals never have velvet.

Horns are found on members of family Bovidae, the cloven hoofed ruminants, including cattle, bison, water buffalo, antelope, sheep, goats and muskoxen. I think readers will agree that this male Desert Bighorn Sheep has spectacular horns.

Horns:

• have a bony core that is covered with a thick sheath of keratin (the protein that hair, fingernails and hooves are made of). It’s the keratin that we actually see.
• most horns are never branched, are never shed and grow throughout the life of the animal
• are typically found on both males and females though they’re much smaller on females
• shape and size vary considerably

So an adult horned mammal of either sex will always have its horns while antlered mammals only have antlers in season (usually) and only on males (usually).

This female Mountain Bighorn Sheep is an example of a female having much smaller horns.

Male bighorns can actually be aged by counting the growth rings (annuli) on their horns. At this angle we can see three distinct growth rings on his left horn. Determining age accurately is just a little bit tricky but if you’re interested in how it’s done you may want to visit this link.

There are a few minor exceptions to some of the “rules” I’ve provided above and the Pronghorn is one of them. Pronghorns have horns (made of keratin) but like antlers they’re shed annually and regrown, leaving the bony core behind in the interim. Pronghorns are the only mammals to have branched horns.

Pronghorns are commonly and incorrectly called antelope (witness Antelope Island and Home On The Range – “where the deer and the antelope play”) but they aren’t at all closely related to true antelope which are all native to the Old World. Pronghorns are the only surviving members of family Antilocapridae and their closest living relatives are the giraffes and okapi of Africa.

Then there are animals that don’t neatly fit either definition very well. Giraffes have ossicones – made of ossified cartilage covered with skin. The horns of rhinos are made completely out of keratin – no bone. Some horned lizards have true horns with a bony core, while the “horns” of other horned lizards are made of specialized body scales with no bone.

To make things even more confusing, sometimes horns and antlers are deformed for various reasons and don’t fit any logical description regarding shape.

This buck Pronghorn roamed Antelope Island for several years and became almost famous amongst my friends and acquaintances who are bird and wildlife photographers. He had the most screwed up horns I’ve ever seen on any mammal. I affectionately called him Curlicue, but I know others who called him Twisty. It was always a good day on the island when I found Curlicue.

OK, I’ve probably beaten this antler vs. horn thing to death but that distinction has always been an important one for me. Anyone who ever took my Utah wildlife or zoology classes at South High School and then Highland High School definitely knew the difference(s) before they passed my class.

Ron