Notes

Many animals grow horns. Sheep, antelope, goat, and cattle can grow horns of all different sizes and shape. Some horns can be 6 inches long, while some can reach up to 3 feet! They are also really thick. Antlers tend to shed, but animals with horns keep the same pair for their whole life. What are horns made up of? Horns are made of a bone core coated with keratin, a protein that is also found in hair and fingers!
The only animal species that grow horns are deer. Antlers are made entirely with bone. Every year, they will shed the antlers and grow a new pair. Reindeer, or caribou, are the only known species to have the male and female grow antlers. Antlers, like horns, come in different shapes and sizes.
Tusks are like horns, but they are actually teeth. You know that "unicorn horn" you can find on narwhals? They are actually tusks, and on males, they can grow up to 9 feet long! Male and female African Elephants can grow tusks, but only male Asian Elephants grow tusks.