What are narwhal horns made of?

The narwhal's horn, also known as a tusk, is an elongated canine tooth. It is made of dentine, a semi-hard tissue that is the main component of teeth and tusks. Dentine is composed of tiny tubules, which contain nerve endings and blood vessels. The outer layer of the narwhal's horn is covered with a thin layer of enamel, which protects the tooth from wear and tear.