We have many animals in North America that have antlers. How are these different from horns and what purpose do they serve?
Antlers are found on animals that are part of the Cervidae family. This includes animals like deer, moose, and elk.1&2 Meanwhile, horns are found in the Bovinae family, which includes cows, goats, and sheep.1&3 Horns are covered in keratin and tend to be found on both males and females in this group, while antlers are made of bone and usually are only found on males.1
Another big difference between the two is that antlers grow from their tip while horns grow from their base. Antlers are also shed every year, while horns are permanent.2 Bigger antlers are a sign that a male is healthy – as it takes a lot of energy to grow large antlers – and they’re used to both impress females during the breeding season and to express dominance over other males during this time.3
After breeding season, animals with antlers will shed their antlers. A couple of weeks after shedding, they’ll begin the process of growing them again. The antlers will usually grow in the same way every year, with the exception of the animal being injured, which can interfere with growth.3
The signals of shorter days lower testosterone in these animals, and thus begins a process that weakens the area where the antler is connected to the skull. They don’t always lose both antlers at the same time but may drop them at different times. These antlers are rich sources of nutrients, such as calcium or phosphorus, and become a vital source of nutrition for other animals within the forest habitats where they’re dropped.2