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Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum is worn away on the tip of the tooth, does enamel show. [17]
The common name was chosen because the part of the tooth that protrudes from the gums (unlike the strap-like teeth of strap-toothed whales) has a shape similar to the tip of a flensing spade as used by 19th-century whalers. Despite the rather similar dentition, the spade-toothed whale and strap-toothed whale seem to be only distantly related.
The narwhal was scientifically described by Carl Linnaeus in his 1758 publication Systema Naturae. [5] The word "narwhal" comes from the Old Norse nárhval, meaning 'corpse-whale', which possibly refers to the animal's grey, mottled skin and its habit of remaining motionless when at the water's surface, a behaviour known as "logging" that usually happens in the summer.
Odontocetes, such as the sperm whale, possess teeth with cementum cells overlying dentine cells. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum is worn away on the tip of the tooth, does enamel show.
Skull of a cross between a narwhal and a beluga whale, at the Zoological Museum, Copenhagen. The beluga was first described in 1776 by Peter Simon Pallas. [1] It is a member of the family Monodontidae, which is in turn part of the parvorder Odontoceti (toothed whales). [1]
Engraved on the tooth is a picture of the ship Francis, which artist Fred Myrick served on during the early 1800s. Now, sperm whales are protected under the Marine Mammal Protection Act. So, in ...
Cuvier's beaked whale is an odontocete — or toothed whale. Erupted teeth are only present in the adult males. [18] Males also develop two tusks in the right and left corners of their lower jaw. The tusks are possibly used for dueling between the males, though it has not been observed, but may also be used for fighting off threats such as orcas.
Researchers found an increase in common dolphin sightings in the English Channel and Hebrides, and a decline in white-beaked dolphins in the Hebrides.