Title: Narwhal Facts - Earth's Endangered Creatures
Headings: Narwhal
Narwhal
Endangered Species of Our Planet

Content: It is possibly also related to the Irrawaddy dolphin. Description
The most conspicuous characteristic of male narwhal is their single extraordinarily long tusk, an incisor that projects from the left side of the upper jaw and forms a left-handed helix. The tusk can be up to 3 metres (nearly 10 ft) long (compared with a body length of 7–8 m [23–26 ft]) and weigh up to 10 kilograms (22 lbs). About one in 500 males has two tusks, which occurs when the right tooth, normally small, also grows out. Although rare, a female narwhal may also produce a tusk. There is a single recorded case of a female with two tusks. The purpose of the tusk has been the subject of much debate. Early scientific theories suggested that the tusk was used to pierce the ice covering the narwhal's Arctic Sea habitat. Others suggested the tusk was used in echolocation. More recently, scientists believed the tusk is primarily used for showmanship and for dominance: