This topic came up in a conversation I had some time back, and since there’s still plenty of confusion about what a horn is vs. an antler, I drew up this handy-dandy one-page guide! Also, as a side note keratin horns degrade relatively quickly when exposed to the elements, which is why you don’t really find fossilized horns (other than the bone cores attached to the skull) whereas fossilized antlers are common. 

A couple of notes on common names of the species I chose: first, mountain goats aren’t actually goats! They’re the only living member of the genus Oreamnos; the only other member went extinct at the end of the Pleistocene, about 13,000 years ago. Also, pronghorn antelope aren’t true antelope. Not only is the pronghorn the only surviving member of its genus, it’s the only surviving member of the family Antilocapridae. So both mountain goats and pronghorn are the last remnants of groups that were much more numerous during the last Ice Age, and we are fortunate to still have them in part because they help give us some idea of what their extinct cousins may have looked like, something we don’t always have with extinct species.

Species portrayed: Columbian black-tailed deer (Odocoileus hemionus columbianus), mountain goat (Oreamnos americanus), pronghorn antelope (Antilocapra americana)