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Animals where this occurs include antelopes, musk-deer, camels, horses, wild boar, some apes, seals, narwhal, and walrus. [6] Male dogs have larger canines with different contour than do females. [7] Humans have the proportionately smallest male canine teeth among all anthropoids and exhibit relatively little sexual dimorphism in canine tooth size.
Nocturnal animals (for example, tarsiers) and animals that live in open landscapes have larger eyes. The vision of forest animals is not so sharp, and in burrowing underground species (moles, gophers, zokors), eyes are reduced to a greater extent, in some cases (marsupial moles, mole rats, blind mole), they are even covered by a skin membrane.
Even without moving their eyes, some birds have a 360-degree field of view. Some other animals – usually, but not always, predatory animals – have their two eyes positioned on the front of their heads, thereby allowing for binocular vision and reducing their field of view in favor of stereopsis.
"At this time we see a flurry of evolution in the forerunners of mammals, such as Dimetrodon, an animal the size of a mountain lion that looked something like a big lizard with a giant sail on its ...
(The largest two teeth of the top and bottom rows of teeth.) A fang is a long, pointed tooth. [1] In mammals, a fang is a modified maxillary tooth, used for biting and tearing flesh. In snakes, it is a specialized tooth that is associated with a venom gland (see snake venom). [2] Spiders also have external fangs, which are part of the chelicerae.
Front view of land snail showing upper and lower sets of tentacles Abalone showing pallial tentacles. Many molluscs have tentacles of one form or another. The most familiar are those of the pulmonate land snails, which usually have two sets of tentacles on the head: when extended the upper pair have eyes at their tips; the lower pair are chemoreceptors.
Tusks are generally curved and have a smooth, continuous surface. The male narwhal's straight single helical tusk, which usually grows out from the left of the mouth, is an exception to the typical features of tusks described above. Continuous growth of tusks is enabled by formative tissues in the apical openings of the roots of the teeth. [2] [3]
The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as a food source for the whale. Baleen is similar to bristles and consists of keratin, the same substance found in human fingernails, skin and hair. Baleen is a skin derivative. Some whales, such as the bowhead whale, have