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An early birth removes a developing marsupial from its mother's body much sooner than in placentals; thus marsupials have not developed a complex placenta to protect the embryo from its mother's immune system. Though early birth puts the tiny newborn marsupial at greater environmental risk, it significantly reduces the dangers associated with ...
There have been six autism-related genes that are linked to the X chromosome when it comes to autistic spectrum disorder. 5 The first gene that has been linked to autism is the Fragile X mental retardation gene (Fmr1). For example, rodents with this gene exhibit elevated cortical spine densities that are similar to those found in autism as well ...
A marsupial has a short gestation period, typically shorter than its estrous cycle, and gives birth to an underdeveloped newborn that then undergoes further development; in many species, this takes place within a pouch-like sac, the marsupium, located in the front of the mother's abdomen.
Among mammals, marsupials and most rodents are altricial. Domestic cats, dogs, and primates, such as humans, are some of the best-known altricial organisms. [14] For example, newborn domestic cats cannot see, hear, maintain their own body temperature, or gag, and require external stimulation in order to defecate and urinate. [15]
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.
Altricial young (marsupials, rodents) are completely helpless and dependent on their mothers, precocial young (elephants, cattle) have highly developed sensory and motor functions at birth, and primates who are semi-helpless young, have an intermediate level of maturation. This variation in maturation at birth requires different maternal care ...
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
It was the first marsupial to have its genome sequenced. The gray short-tailed opossum is used as a research model in science, [4] and is also frequently found in the exotic pet trade. It is also known as the Brazilian opossum, rainforest opossum and in a research setting the laboratory opossum.