Placental Mammals, VIV-ZOR
Placental mammal, (infraclass Eutheria), any member of the mammalian group characterized by the presence of a placenta, which facilitates exchange of nutrients and wastes between the blood of the mother and that of the fetus. The placentals include all living mammals except marsupials and monotremes. Although some authorities consider the marsupials (cohort Marsupialia) to be placental mammals, these animals have a less-developed, less-efficient type of placenta that limits the gestation period. The true placenta of the placentals allows for a longer developmental period within the protection of the womb, a factor considered to have contributed to the evolutionary success of the group. Fossil evidence shows that the first placental mammals evolved between about 163 million and 157 million years ago during the Jurassic Period (201.3 million to about 145 million years ago).
Placental Mammals Encyclopedia Articles By Title
viverrid, (family Viverridae), any of 35 species of small Old World mammals including civets, genets, and linsangs.......
Vizsla, breed of sporting dog whose ancestors were probably brought to Hungary by the Magyars more than a thousand......
vole, any of numerous species of small-bodied mouselike rodents of the Northern Hemisphere that are classified,......
Wagyu, slow-growing Japanese cattle breed prized for its tender, flavorful, and highly marbled meat. Evidence suggests......
walrus, (Odobenus rosmarus), huge, seal-like mammal found in Arctic seas. There are two subspecies: the Atlantic......
warthog, (Phacochoerus aethiopicus), member of the pig family, Suidae (order Artiodactyla), found in open and lightly......
water buffalo, (Bubalus bubalis), either of two forms, wild and domestic, of Asian mammal similar to the ox. There......
water rat, any of 18 species of amphibious carnivorous rodents. They exhibit many adaptations associated with hunting......
water shrew, any of 12 species of amphibious shrews that have a broad, fleshy muzzle, large chest, and long hind......
waterbuck, antelope species of the genus Kobus...
weasel, any of various small carnivores with very elongated slender bodies. Most live in the Northern Hemisphere......
Weddell seal, (Leptonychotes weddellii), nonmigratory earless seal (family Phocidae) found around the South Pole,......
Weimaraner, sporting dog breed developed in the early 19th century by German nobles of the court of Weimar. First......
Welsh Corgi, either of two breeds (Pembroke Welsh Corgi and Cardigan Welsh Corgi) of affectionate dogs developed......
Welsh pony, breed of small horse popular as a child’s or an adult’s mount. A hardy breed that developed in the......
Welsh terrier, breed of terrier native to Wales, where it has been used as a hunter of foxes, otters, and badgers.......
West Highland white terrier, a short-legged dog standing 10 to 11 inches (25 to 28 cm) tall and weighing 13 to......
whale, any of the larger species of aquatic mammals belonging to the order Cetacea. The term whale can be used......
Giraffes, as browsers, primarily feed on new, tender shoots and leaves of trees, with a particular fondness for......
Whales have a diverse diet that varies significantly between species, primarily depending on whether they are baleen......
The sperm whale is the loudest animal on Earth. These majestic creatures can produce sounds that reach an astonishing......
While river otters and sea otters might appear similar at first glance, the two exhibit many striking differences......
whippet, hound breed developed in mid-19th-century England to chase rabbits for sport in an arena. The breed was......
white tiger, colour variant of the Bengal tiger (Pantheria tigris tigris), the Siberian tiger (P. tigris altaica),......
white-tailed deer, (Odocoileus virginianus), common American deer of the family Cervidae (order Artiodactyla) that......
white-toothed shrew, (genus Crocidura), any of 164 species of mouse-sized African and Eurasian insectivores making......
Amazon river dolphins, also known as botos, are often pink due to a combination of factors, including their diet,......
Black cats are considered unlucky in some cultures because of superstitious beliefs that have been passed down......
The name Boxer is derived from the dog’s unique behavior during play and combat, which is reminiscent of a human......
Dogs are loyal due to their evolutionary history, domestication process, and the strong bonds they form with humans.......
Beavers are quite the clever architects when it comes to safeguarding their homes. They build dams to raise the......
Cats blink slowly as a form of nonverbal communication, often interpreted as a sign of trust and affection toward......
Cats clean themselves frequently because of a combination of health benefits and social behaviors. Cats are meticulous......
Cats have slit pupils primarily to enhance their ability to see in varying light conditions. They are crepuscular......
Cats are drawn to boxes primarily because these enclosed spaces offer a sense of safety and comfort. By nature......
The aromatic leaves of the catnip (Nepeta cataria), a herb of the mint family, are known to be particularly exciting......
Cats are naturally inclined to use scratching posts because it fulfills several instinctual needs and behaviors.......
While purring is often associated with a cat’s contentment, such as when they are being petted or snuggled up in......
Dogs eat grass for several reasons, and while the exact motivations can vary, there are a few common theories that......
Dogs wag their tails primarily as a form of communication, allowing them to express a range of emotions. Tail wagging......
The long neck of a giraffe (genus Giraffa) is a classic example of adaptation, which is the process by which a......
Chest beating is a powerful tool in the gorilla’s communication arsenal. Both males and females engage in this......
Llamas spit for a number of reasons. When a llama feels threatened, it might spit to protect itself or to maintain......
Whale songs serve as a means of communication among individuals and groups. These vocalizations help whales share......
There are several theories about why zebras have stripes. Scientists believe that one of the main reasons is camouflage......
Touching a manatee is illegal in the United States. The ban’s aim is to protect these vulnerable marine mammals......
wildcat, (species Felis silvestris), a small wild member of the cat family (Felidae) native to Eurasia and Africa.......
wolf, any of two species of wild doglike carnivores. The gray, or timber, wolf (Canis lupus) is the better known.......
wolverine, (Gulo gulo), member of the weasel family (Mustelidae) that lives in cold northern latitudes of North......
wood mouse, (genus Apodemus), any of about 20 species of small-bodied rodents found from northern Europe eastward......
woodland vole, (Microtus pinetorum), a small mouselike rodent of the eastern United States that is well adapted......
woodrat, (genus Neotoma), any of 23 species of medium-sized North American and Central American rodents. Some species......
woolly mammoth, (Mammuthus primigenius), extinct species of elephant found in fossil deposits of the Pleistocene......
woolly monkey, any of five species of densely furred South American primates found in rainforests of the western......
woolly rhinoceros, (genus Coelodonta), either of two extinct species of rhinoceros found in fossil deposits of......
woolly spider monkey, (genus Brachyteles), extremely rare primate that lives only in the remaining Atlantic forests......
working dog, any of various breeds of dog bred as guard, herding, draft, or rescue animals. Breeds range from medium......
xenarthran, (magnorder Xenarthra), an ancient lineage of mammals comprising the armadillos (order Cingulata) and......
yak, (Bos grunniens), long-haired, short-legged oxlike mammal that was probably domesticated in Tibet but has been......
Yorkshire, breed of swine produced in the 18th century by crossing the large indigenous white pig of North England......
Yorkshire Terrier dog, breed of toy dog developed about the mid-1800s in the English counties of Yorkshire and......
zebra, any of three species of strikingly black-and-white striped mammals of the horse family Equidae (genus Equus):......
zokor, (genus Myospalax), any of seven north Asian species of subterranean rodents. Zokors are molelike animals......
zorille, (Ictonyx [sometimes Zorilla] striatus), African carnivore of the weasel family (Mustelidae), frequenting......