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Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia.They are natively found in Australasia, Wallacea, and the Americas.One of marsupials' unique features is their reproductive strategy: the young are born in a relatively undeveloped state and then nurtured within a pouch on their mother's abdomen.
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.
Due to the fact that placental mammals and marsupials nourish their developing embryos via the placenta, the ovum in these species does not contain significant amounts of yolk, and the yolk sac in the embryo is relatively small in size, in comparison with both the size of the embryo itself and the size of yolk sac in embryos of comparable developmental age from lower chordates.
A boa constrictor in the U.K. gave birth to 14 babies — without a mate. The process is called parthenogenesis, from the Greek words for “virgin” and “birth.” It tends to occur in ...
The mammals included are only viviparous (marsupials and placentals) as some mammals, which are monotremes (including platypuses and echidnas) lay their eggs. A marsupial has a short gestation period, typically shorter than placental. For more information on how these estimates were ascertained, see Wikipedia's articles on gestational age.
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.
They have one opening for excretion and reproduction called the cloaca. They hold the eggs internally for several weeks, providing nutrients, and then lay them and cover them like birds . Like marsupial " joeys ", monotreme " puggles " are larval and fetus-like, [ 9 ] as like them they cannot expand their torso due to the presence of epipubic ...
An aquarium in South Africa is stretched beyond capacity after more than 500 baby sea turtles were washed up on beaches by a rare and powerful storm and rescued by members of the public.