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Female beaked whales' teeth are hidden in the gums and are not visible, and most male beaked whales have only two short tusks. Narwhals have vestigial teeth other than their tusk, which is present on males and 15% of females and has millions of nerves to sense water temperature, pressure and salinity.
In modern toothed whales, this fat pad in the mandibular foramen extends posteriorly to the middle ear. This allows sounds to be received in the lower jaw, and then transmitted through the fat pad to the middle ear. Similar to pakicetids, the orbits of ambulocetids are on the top of the skull, but they face more laterally than in pakicetids. [18]
Whales have two flippers on the front, and a tail fin. These flippers contain four digits. Although whales do not possess fully developed hind limbs, some, such as the sperm whale and bowhead whale, possess discrete rudimentary appendages, which may contain feet and digits.
[3] [4] Parts recovered include the jaw, front and hind legs, bits of spine, and tail. Olivier Lambert, a scientist at the Royal Belgian Institute of Natural Sciences and lead author of the study, noted that Peregocetus "fills in a crucial [knowledge] gap" about the evolution of whales and their spread.
[51]: 446 The vestigial hind legs are enclosed inside the body. Rorquals need to build speed to feed, and have several adaptions for reducing drag, including a streamlined body; a small dorsal fin, relative to its size; and lack of external ears or hair. The fin whale, the fastest among baleen whales, can travel at 37 kilometers per hour (23 mph).
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.
Baleen whales have two flippers on the front, near the head. Like all mammals, baleen whales breathe air and must surface periodically to do so. Their nostrils, or blowholes, are situated at the top of the cranium. Baleen whales have two blowholes, as opposed to toothed whales which have one.
The melon is structurally part of the nasal apparatus and comprises most of the mass tissue between the blowhole and the tip of the snout. The function of the melon is not completely understood, but scientists believe it is a bioacoustic component, providing a means of focusing sounds used in echolocation and creating a similarity between characteristics of its tissue and the surrounding water ...