Placental Mammals, CHE-ENA
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
cheetah, (Acinonyx jubatus), one of the world’s most-recognizable cats, known especially for its speed. Cheetahs’......
Chesapeake Bay retriever, breed of sporting dog, developed in the United States in the 19th century to retrieve......
Cheviot, breed of hardy, medium-wool, white-faced, hornless sheep developed in Scotland and Northumberland, England.......
chevrotain, (family Tragulidae), any of about 10 species of small, delicately built, hoofed mammals that constitute......
Chihuahua dog, smallest recognized dog breed, named for the Mexican state of Chihuahua, where it was first noted......
chimpanzee, (Pan troglodytes), species of ape that, along with the bonobo, is most closely related to humans. Chimpanzees......
chinchilla, (genus Chinchilla), either of two South American species of medium-sized rodents long valued for their......
chinchilla rat, any of six South American species of rodents that superficially resemble a chinchilla but are more......
Chinese crested, breed of toy dog of ancient ancestry; it is one of the hairless breeds, its coat being confined......
Chinese Shar-Pei, breed of medium-sized dog noted for its loose skin and wrinkles. Once considered to be among......
Chinese water deer, (Hydropotes inermis), very small Asian deer of the family Cervidae (order Artiodactyla), native......
chipmunk, (genus Tamias), any of 25 species of small, striped, terrestrial squirrels with large internal cheek......
chiru, (Panthalops hodgsoni), a small, gregarious, graceful antelope-like mammal of the family Bovidae (order Artiodactyla)......
chital, (Cervus axis, sometimes Axis axis), Asiatic deer, belonging to the family Cervidae (order Artiodactyla).......
Chow Chow, one of the oldest of dog breeds noted for its lionlike mane, its profuse double coat, its blue-black......
civet, any of a number of long-bodied, short-legged carnivores of the family Viverridae. There are about 15 to......
Cleveland Bay, breed of horse notable for its strength, endurance, and beauty and for its prepotency—i.e., its......
cloud rat, any of six species of slow-moving, nocturnal, tree-dwelling rodents found only in Philippine forests.......
clouded leopard, strikingly marked cat, very similar in colouring and coat pattern to the smaller, unrelated marbled......
Clumber spaniel, breed of sporting dog, the heaviest of the spaniel family, said to have originated in France before......
Clydesdale, heavy draft-horse breed that originated in Lanarkshire, Scotland, near the River Clyde. The breed was......
coati, (genus Nasua), any of three species of omnivore related to raccoons (family Procyonidae). Coatis are found......
cocker spaniel, either of two breeds of sporting dogs used by hunters to flush game birds from cover; it is also......
collie, working dog breed developed in Great Britain, probably by the 18th century. There are two varieties of......
colobus, any of some dozen species of long-tailed tree-dwelling and generally gregarious monkeys native to eastern,......
Condylarthra, extinct group of mammals that includes the ancestral forms of later, more-advanced ungulates (hoofed......
Connemara, breed of pony native to the Connemara area of Ireland, used as general riding ponies for adults and......
coonhound, any of several breeds of dogs used primarily in hunting raccoons by scent. Coonhounds are noted for......
Coryphodon, genus of extinct primitive hoofed mammals known from Late Paleocene and Early Eocene deposits (those......
cotton rat, (genus Sigmodon), any of 14 species of terrestrial rodents found from the southern United States to......
cottontail, any of several North and Central American rabbit species of the genus Sylvilagus. See...
cow, in common parlance, a domestic bovine, regardless of sex and age, usually of the species Bos taurus. In precise......
coydog, hybrid of the domestic dog with the coyote...
coyote, (Canis latrans), New World member of the dog family (Canidae) that is smaller and more lightly built than......
crab-eating fox, (Cerdocyon thous), South American member of the dog family (Canidae), found in grassy or forested......
crabeater seal, (species Lobodon carcinophagus), southern seal of the family Phocidae found among drifting ice......
Creodonta, order of extinct carnivorous mammals first found as fossils in North American deposits of the Paleocene......
crested black macaque, (Macaca nigra), a mainly arboreal Indonesian monkey named for the narrow crest of hair that......
Criollo, horse breed of Argentina, Brazil, and other South American countries, used as a stock and riding horse.......
Cro-Magnon, population of early Homo sapiens dating from the Upper Paleolithic Period (c. 40,000 to c. 10,000 years......
curly-coated retriever, breed of sporting dog bred and trained to retrieve game both on land and in the water.......
cutting horse, light saddle horse trained to cut (isolate) livestock, especially cattle, from herds. Most are quarter......
Dachshund, dog breed of hound and terrier ancestry developed in Germany to pursue badgers into their burrows. The......
Cattle, at the initial stages of their domestication, produced a relatively small amount of milk, sufficient only......
Dall sheep, (Ovis dalli), species of bighorn...
Dalmatian, dog breed named after the Adriatic coastal region of Dalmatia, Croatia, its first definite home. The......
Dandie Dinmont terrier, breed of terrier developed in the border country of England and Scotland. First noted as......
Dartmoor, breed of pony about 12 hands (48 inches, or 122 cm) tall, hardy, and semiwild in its native Dartmoor,......
dassie rat, (Petromus typicus), a medium-sized rodent adapted to life among rocky outcrops in the desert hills......
DeBrazza’s monkey, (Cercopithecus neglectus), large brightly coloured guenon widely distributed through central......
deer, (family Cervidae), any of 43 species of hoofed ruminants in the order Artiodactyla, notable for having two......
deer mouse, (genus Peromyscus), any of 53 species of small rodents found in a variety of habitats from Alaska and......
degu, (genus Octodon), one of four species of ratlike South American rodents found primarily on the lower western......
Denisovan, member of a group of archaic humans who emerged about 370,000 years ago during the Pleistocene Epoch......
desert dormouse, (Selevinia betpakdalaensis), a rarely seen or captured small rodent of Central Asia. Weighing......
desman, either of two species of amphibious Eurasian moles that den on land but seek prey underwater instead of......
dhole, (Cuon alpinus), wild Asian carnivore of the dog family (Canidae), found in central and southeastern wooded......
diana monkey, (Cercopithecus diana), arboreal species of guenon named for its crescent-shaped white browband that......
dibatag, (Ammodorcas clarkei), a rare member of the gazelle tribe (Antilopini, family Bovidae), indigenous to the......
TV shows such as The Flintstones depict humans and dinosaurs living together in harmony. But that’s just fiction,......
Yes, humans lived during the same time period as saber-toothed cats. Now extinct, saber-toothed cats existed from......
dik-dik, (genus Madoqua), any of four species of dwarf antelopes (tribe Neotragini, family Bovidae) that are adapted......
dingo, (Canis lupus dingo, Canis dingo), member of the family Canidae native to Australia. Most authorities regard......
Dinohyus, extinct genus of giant piglike mammals found as fossils in deposits of early Miocene age in North America......
dire wolf, (Aenocyon dirus), canine that existed during the Pleistocene Epoch (2.6 million to 11,700 years ago).......
disk-winged bat, (family Thyropteridae), any of three species of bats inhabiting Central America and northern South......
Not all donkeys have a cross on their back, but most of them do. The distinctive cross pattern consists of a dark......
Camels have long been known for their ability to go weeks at a time without needing to drink water—an ability that......
Schizophrenia—any of several severe mental disorders having such symptoms as hallucinations, disorganized thinking,......
Cows are notorious for their emissions of methane (CH4), a greenhouse gas. Cows produce methane through digestion,......
Yes, elephants have good memory. For example, they are able to return to the locations of vital water and food......
The spotted, or laughing, hyena (Crocuta crocuta) is a ruthless scavenger and killer, burglarizing food stores,......
Lemmings are small creatures with wild reputations. In the 17th century, naturalists perplexed by the habit of......
Mongooses are unlikely to rank anywhere on lists of the most popular or lowest-maintenance pets because, frankly,......
Raccoons are known to dip their food in and out of water when they eat near a water source. This behavior has earned......
Yes, whales can have teeth. Specifically, toothed whales, called odontocetes, are a diverse group of cetaceans......
Whales do sleep, but their sleep is quite different from what we typically understand as sleep in humans. Whales,......
Doberman Pinscher, breed of working dog developed in Apolda, Germany, by Karl Friedrich Louis Dobermann, a tax......
dog, (Canis lupus familiaris), domestic mammal of the family Canidae (order Carnivora). It is a subspecies of the......
Dogo Argentino, breed of working dog created in Argentina in the 1920s as a pack-hunting, big-game hunter. The......
dolphin, any of the toothed whales belonging to the mammal family Delphinidae (oceanic dolphins) as well as the......
domestic shorthair, breed of domestic cat often referred to as a common, or alley, cat; a good show animal, however,......
donkey, (Equus asinus), domestic ass belonging to the horse family, Equidae, and descended from the African wild......
dormouse, (family Myoxidae), any of 27 species of small-bodied Eurasian, Japanese, and African rodents. The largest,......
douc, (genus Pygathrix), any of three colourful species of langur monkeys found in the tropical forests of central......
drill, (Mandrillus leucophaeus), large short-tailed monkey found from southeastern Nigeria to western Cameroon......
dromedary, Arabian (one-humped) riding camel (Camelus dromedarius), a swift domestic species not found in the wild.......
Dryopithecus, genus of extinct ape that is representative of early members of the lineage that includes humans......
dugong, (Dugong dugon), marine mammal that inhabits the warm coastal waters of the Indian and Pacific Oceans, feeds......
duiker, (tribe Cephalophini), any of 17 or 18 species of forest-dwelling antelopes (subfamily Cephalophinae, family......
Duroc, breed of pig developed between 1822 and 1877 from the Old Duroc pig of New York and the Red Jersey pig of......
durukuli, (genus Aotus), any of several species of closely related nocturnal monkeys of Central and South America......
Once upon a time, Lil BUB met Grumpy Cat. It was not love at first sight for two of the most-famous Internet cats:......
Ehringsdorf remains, human fossils found between 1908 and 1925 near Weimar, Germany. The most complete fossils......
eland, (genus Taurotragus), either of two very large, oxlike African antelopes of the spiral-horned antelope tribe......
elephant, (family Elephantidae), largest living land animal, characterized by its long trunk (elongated upper lip......
elephant seal, either of the two largest pinnipeds (aquatic mammals of the suborder Pinnipedia): the northern elephant......
elephant shrew, (order Macroscelidea), any of approximately 20 species of rat-sized African mammals named for their......
elk, (Cervus elaphus canadensis), the largest and most advanced subspecies of red deer (Cervus elaphus), found......
Enaliarctos, extinct genus of mammals that contains the oldest known member of Pinnipedia, the group that contains......