Search results
Results from the WOW.Com Content Network
Marsupials Temporal range: Paleocene–Recent Pre๊ ๊ O S D C P T J K Pg N Possible Late Cretaceous records Clockwise from left: eastern grey kangaroo, Virginia opossum, long-nosed bandicoot, monito del monte and Tasmanian devil representing the orders Diprotodontia, Didelphimorphia, Peramelemorphia, Microbiotheria and Dasyuromorphia respectively Scientific classification Domain: Eukaryota ...
The latter subclass is divided into two infraclasses: pouched mammals (metatherians or marsupials), and placental mammals (eutherians, for which see List of placental mammals). Classification updated from Wilson and Reeder's "Mammal Species of the World: A Taxonomic and Geographic Reference" using the "Planet Mammifères" website.
In marsupials, the uterus forms as a duplex organ of two uteri. In monotremes such as the platypus , the uterus is duplex and rather than nurturing the embryo, secretes the shell around the egg. It is essentially identical with the shell gland of birds and reptiles, with which the uterus is homologous .
The pouch is a distinguishing feature of female marsupials and monotremes, [1] [2] [3] and rarely in males as well, such as in the yapok [4] and the extinct thylacine. The name marsupial is derived from the Latin marsupium, meaning "pouch". This is due to the occurrence of epipubic bones, a pair of bones projecting forward from the pelvis
Like most marsupials, female kangaroos have a pouch called a marsupium in which joeys complete postnatal development. Because of its grazing habits, the kangaroo has developed specialized teeth that are rare among mammals. Its incisors are able to crop grass close to the ground and its molars chop and grind the grass. Since the two sides of the ...
The mammalian female reproductive system contains three main divisions: the vagina and uterus, which act as the receptacle for the sperm, the ovaries, which produce the female's ova, and the vulva, which consists of the labia and clitoris. The vagina, uterus and ovaries are always internal while the vulva is external.
As marsupials, female opossums have a reproductive system that includes a bifurcated vagina and a divided uterus; many have a pouch. [29] The average estrous cycle of the Virginia opossum is about 28 days. [30] Opossums do possess a placenta, [31] but it is short-lived, simple in structure, and, unlike that of placental mammals, not fully ...
In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the fetus at a developmental stage when it is ready to feed and breathe. In some species, the offspring is precocial and can move around almost immediately after birth but in others, it is altricial and completely dependent on ...