In medieval times, its long, straight tusk was often given to royalty, passed off as a "unicorn horn." In the 16th century, a narwhal tusk worth $10,000 was given to Queen Elizabeth.

  Narwhals give birth to a baby calf every 3 years. The narwhal's pregnancy lasts 14 months, and then the baby is born in the spring. When the baby is born, its all white. 

  Polar bears, killer whales, sharks, and eat narwhals. The narwhal's greatest predator is a killer whale. Narwhals avoid killer whales by staying in between the cracks of glaciers in the winter. Killer whales are unable to stay there because they are too big to fit. Another reason is because killer whales have dorsal fins, which hinder their ability to squeeze through tight spaces. Narwhals don't have dorsal fins.