What is the difference between antlers and horns?

Antlers are branching bony appendages that are shed annually. All male cervids , like moose, deer and elk have antlers. Only caribou and reindeer have females with antlers, though much smaller than their male counterparts. When they grow, they are covered in a thin fuzzy skin covering called "velvet" which contains blood supply to help the antlers grow. This skin covering is shed before rutting season.

Horns are a pointed projection of skin and hair of an animal, consisting of a layer of keratin surrounding a living bone core. Animals that have horns include all those in the family Bovidae (bovines, sheep, goats and antelope). Horns usually have a spiral or curved shape, with ridges or fluting. Horns begin growth soon after birth, and continue growth until the animal dies. They never fall off every year, except in pronghorns, where they shed the outer shell every year, but retain the inner bony core. Only the males of most species of Bovidae have horns, except those of the bovine genus including bison, buffalo, gnu and domestic cattle.