Placental Mammals, 9 (-BLA

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).
Back To Placental Mammals Page

Placental Mammals Encyclopedia Articles By Title

9 (Lives of) Famous Cat Lovers
Cats are among the most beloved pet animals in the world. Second only to dogs as the most common pet of choice,......
aardvark
aardvark, (Orycteropus afer), stocky African mammal found south of the Sahara Desert in savanna and semiarid areas.......
aardwolf
aardwolf, (Proteles cristatus), insectivorous carnivore that resembles a small striped hyena. The shy, mainly nocturnal......
Abyssinian
Abyssinian, breed of domestic cat, probably of Egyptian origin, that has been considered to approximate the sacred......
acouchy
acouchy, (genus Myoprocta), either of two species of South American rodents that resemble the small tropical-forest-dwelling......
adapiform
adapiform, any of several dozen extinct species of primates of the suborder Strepsirrhini (a group that includes......
addax
addax, (Addax nasomaculatus), the most desert-adapted African antelope, formerly found throughout most of the Sahara......
affenpinscher
affenpinscher, breed of toy dog known since the 17th century. It is thought to have originated in Germany, where......
Afghan hound
Afghan hound, breed of dog developed as a hunter in the hill country of Afghanistan. It was once thought to have......
African bush elephant
African bush elephant, (Loxodonta africana), one of two living species of African elephants (genus Loxodonta) and......
African forest elephant
African forest elephant, (Loxodonta cyclotis), one of two living species of African elephants (genus Loxodonta)......
African pouched rat
African pouched rat, (subfamily Cricetomyinae), any of five species of African rodents characterized by cheek pouches......
African spiny mouse
African spiny mouse, (genus Acomys), any of more than a dozen species of small to medium-sized rodents characterized......
African wild dog
African wild dog, (Lycaon pictus), wild African carnivore that differs from the rest of the members of the dog......
African wildcat
African wildcat, (Felis silvestris libyca), small, tabbylike cat (family Felidae) found in open and forested regions......
agouti
agouti, (genus Dasyprocta), any of about a dozen species of tropical American rodents resembling the small forest-dwelling......
Airedale Terrier
Airedale Terrier, the largest of the terriers, called the “King of Terriers,” probably descended from the otterhound......
Akita
Akita, breed of working dog that originated in the mountains of northern Japan. In 1931 the Japanese government......
Alaskan Malamute
Alaskan Malamute, sled dog developed by the Malemiut people of Alaska, from whom it takes its name. The Alaskan......
Albino
Albino, colour type of horse, characterized by pink skin and a pure white coat. Unlike some other colour types,......
alpaca
alpaca, (Vicugna pacos), domesticated South American member of the camel family, Camelidae (order Artiodactyla),......
American Bully
American Bully, breed of muscular companion dog (in contrast to a working dog) created in the United States in......
American Quarter Horse
American Quarter Horse, one of the oldest recognized breeds of horses in the United States. The breed originated......
American Saddlebred horse
American Saddlebred horse, breed of riding horse possessing several easy riding gaits and great vigour and style.......
American spiny rat
American spiny rat, (family Echimyidae), any of at least 80 nocturnal species of medium-sized Central and South......
American Staffordshire Terrier
American Staffordshire Terrier, breed of dog, originally called Staffordshire Terrier when registered with the......
American water spaniel
American water spaniel, breed of sporting dog originating in the United States in the late 1800s, bred to retrieve......
Americas, pony of the
pony of the Americas, riding-pony breed used as a child’s mount, developed in the United States in the 1950s by......
Angora goat
Angora goat, breed of domestic goat originating in ancient times in the district of Angora in Asia Minor. The goat’s......
Angus
Angus, breed of black, polled beef cattle, for many years known as Aberdeen Angus, originating in northeastern......
anomalure
anomalure, (family Anomaluridae), any of seven African species of rodents comprising the large anomalures (genus......
anteater
anteater, (suborder Vermilingua), any of four species of toothless, insect-eating mammals found in tropical savannas......
antelope
antelope, any of numerous Old World grazing and browsing hoofed mammals belonging to the family Bovidae (order......
aoudad
aoudad, (Ammotragus lervia), North African goatlike mammal of the family Bovidae (order Artiodactyla). This species......
ape
ape, (superfamily Hominoidea), any tailless primate of the families Hylobatidae (gibbons) and Hominidae (chimpanzees,......
Appaloosa
Appaloosa, colour breed of horse popular in the United States. The breed is said to have descended in the Nez Percé......
Arabian horse
Arabian horse, earliest improved breed of horse, valued for its speed, stamina, beauty, intelligence, and gentleness.......
Arctic fox
Arctic fox, (Vulpes lagopus), northern fox of the family Canidae, found throughout the Arctic region, usually on......
Ardipithecus
Ardipithecus, the earliest known genus of the zoological family Hominidae (the group that includes humans and excludes......
argali
argali, (Ovis ammon), the largest living wild sheep, native to the highlands of Central Asia. Argali is a Mongolian......
armadillo
armadillo, (family Dasypodidae), any of various armoured mammals found mainly in tropical and subtropical regions......
Arsinoitherium
Arsinoitherium, genus of extinct large, primitive, hoofed mammals that have been found as fossils in Egypt in deposits......
Asian tree mouse
Asian tree mouse, (subfamily Platacanthomyinae), any of three species of small rodents found only in a few tropical......
Asiatic black bear
Asiatic black bear, (Ursus thibetanus), member of the bear family (Ursidae) found from southern Iran to the Himalayas,......
Asiatic lion
Asiatic lion, (subspecies Panthera leo leo), population of lions whose geographic range once extended from Turkey......
ass
ass, either of two species belonging to the horse family, Equidae, especially the African wild ass (Equus africanus)......
Asselar man
Asselar man, extinct human known from a skeleton found in 1927 near the French military post of Asselar, French......
aurochs
aurochs, (Bos primigenius), extinct wild ox of Europe, family Bovidae (order Artiodactyla), from which cattle are......
Australian Cattle Dog
Australian Cattle Dog, breed of herding dog developed in the 19th century to work with cattle in the demanding......
Australian Shepherd
Australian Shepherd, breed of herding dog that, despite its name, was developed in the western United States in......
Australian terrier
Australian terrier, breed of dog that originated as an Australian farm dog. First exhibited in 1885 as the Australian......
Australopithecus
Australopithecus, (genus Australopithecus), group of extinct primates closely related to, if not actually ancestors......
Australopithecus sediba
Australopithecus sediba, extinct primate species that inhabited southern Africa beginning about 1.98 million years......
avahi
avahi, (genus Avahi), long-legged arboreal lemur of Madagascar. Avahis have short arms, a short muzzle, and a round......
aye-aye
aye-aye, (Daubentonia madagascariensis), rare squirrel-like primate of Madagascar, the sole living representative......
Ayrshire
Ayrshire, breed of hardy dairy cattle originating in the county of Ayr, Scotland, in the latter part of the 18th......
babirusa
babirusa, (Babirousa babyrussa), wild East Indian swine, family Suidae (order Artiodactyla), of Celebes and the......
baboon
baboon, (genus Papio), any of five species of large, robust, and primarily terrrestrial monkeys found in dry regions......
Bactrian camel
Bactrian camel, either of two of the three living species of camels inhabiting the steppes and arid regions of......
badger
badger, common name for any of several stout carnivores, most of them members of the weasel family (Mustelidae),......
baleen whale
baleen whale, (suborder Mysticeti), any cetacean possessing unique epidermal modifications of the mouth called......
bamboo rat
bamboo rat, any of four Asiatic species of burrowing, slow-moving, nocturnal rodents. Bamboo rats have a robust,......
bandicoot rat
bandicoot rat, any of five Asiatic species of rodents closely associated with human populations. The greater bandicoot......
banteng
banteng, (species Bos banteng), a species of wild Southeast Asian cattle, family Bovidae (order Artiodactyla),......
barasingha
barasingha, (Cervus duvauceli), graceful deer, belonging to the family Cervidae (order Artiodactyla), found in......
Barb
Barb, native horse breed of the Barbary states of North Africa. It is related to, and probably an offshoot of,......
Barbary macaque
Barbary macaque, (Macaca sylvanus), tailless ground-dwelling monkey that lives in groups in the upland forests......
barbastelle
barbastelle, (genus Barbastella), either of two bats of the vesper bat family, Vespertilionidae, found in Europe......
Barylambda
Barylambda, extinct genus of unusual and aberrant mammals found as fossils in deposits in North America in the......
Basenji
Basenji, ancient breed of hound native to Central Africa, where it has historically lived as a village dog (one......
basilosaurid
basilosaurid, any member of the family Basilosauridae, an early group of whales that lived from the middle Eocene......
Basilosaurus
Basilosaurus, extinct genus of primitive whales of the family Basilosauridae (suborder Archaeoceti) found in Middle......
Basset Hound
Basset Hound, breed of dog developed centuries ago in France and long maintained, chiefly in France and Belgium,......
bat
bat, (order Chiroptera), any member of the only group of mammals capable of flight. This ability, coupled with......
bat-eared fox
bat-eared fox, (species Otocyon megalotis), large-eared fox, belonging to the dog family (Canidae), found in open,......
Batodonoides
Batodonoides, genus of extinct insectivorous mammals that lived during the Eocene Epoch (56 to 33.9 million years......
Beagle
Beagle, small hound dog breed popular as both a pet and a hunter. It looks like a small foxhound and has large......
beaked whale
beaked whale, (family Ziphiidae), any of more than 20 species of medium-sized toothed whales that have an extended......
bear
bear, (family Ursidae), any of eight species of large short-tailed carnivores found in the Americas, Europe, and......
bearded collie
bearded collie, dog breed developed in Great Britain for herding sheep and driving cattle to market; it is one......
bearded seal
bearded seal, (Erignathus barbatus), nonmigratory seal of the family Phocidae, distinguished by the bushy, bristly......
beaver
beaver, (genus Castor), either of two species of amphibious rodents native to North America, Europe, and Asia.......
Bedlington terrier
Bedlington terrier, breed of dog developed in the 1800s in Northumberland, England, and named for Bedlingtonshire,......
beef cattle breeds
All modern domestic cattle are believed to belong to the species Bos taurus (European breeds such as Shorthorn......
beisa
beisa, African antelope, a race of the species Oryx gazella. See ...
Belgian horse
Belgian horse, breed of heavy draft horse descended from the Flemish “great horse,” the medieval battle horse native......
Belgian Malinois
Belgian Malinois, breed of herding and working dog developed in the Malines area of Belgium in the 1800s. The Belgian......
Belgian sheepdog
Belgian sheepdog, working dog developed in the village of Groenendaal, Belgium, in 1885. A long-haired black dog,......
beluga
beluga, (Delphinapterus leucas), a small, toothed whale found mainly in the coastal waters of the Arctic Ocean......
Bengal tiger
Bengal tiger, (subspecies Panthera tigris tigris), subspecies of tiger (Pantheria tigris) inhabiting the hot and......
Berkshire
Berkshire, breed of domestic pig originating in England, where in the early 19th century the name “Berkshire” became......
Bernese Mountain Dog
Bernese Mountain Dog, breed of Swiss working dog taken to Switzerland more than 2,000 years ago by invading Romans.......
Bichon Frise
Bichon Frise, breed of small dog noted for its fluffy coat and cheerful disposition. For many centuries it was......
bighorn sheep
bighorn sheep, (Ovis canadensis), stocky, climbing hoofed mammal of western North America known for its massive......
binturong
binturong, (Arctictis binturong), catlike omnivore of the civet family (Viverridae), found in dense forests of......
birch mouse
birch mouse, (genus Sicista), any of 13 species of small, long-tailed mouselike rodents. Birch mice live in the......
bison
bison, (genus Bison), either of two species of oxlike grazing mammals that constitute the genus Bison of the family......
black bear
black bear, (Ursus americanus), the most common bear (family Ursidae), found in the forests of North America, including......
black panther
black panther, colloquial term used to refer to large felines classified in the genus Panthera that are characterized......

Placental Mammals Encyclopedia Articles By Title