Types : Marsupial Mammal (pouched mammal)
Number of species : 103 or more species in 19 genera.
Size : Length from nose to tail, 2.5 ft (76 cm)
Fun facts : These animals are most famous for "playing possum." When threatened by dogs, foxes, or bobcats, opossums sometimes flop onto their sides and lie on the ground with their eyes closed or staring fixedly into space. They extend their tongues and generally appear to be dead. This ploy may put a predator off its guard and allow the opossum an opportunity to make its escape. Plus, Opossums are excellent tree climbers and spend much of their time aloft. They are aided in this by sharp claws, which dig into bark, and by a long prehensile (gripping) tail that can be used as an extra limb. Opossums nest in tree holes or in dens made by other animals.
Habitat : They live in mainly North America and Canada. To be specific, opossums are found in forest, farmland, grassland, urban and suburban areas, near water.
Number of species : 103 or more species in 19 genera.
Size : Length from nose to tail, 2.5 ft (76 cm)
Fun facts : These animals are most famous for "playing possum." When threatened by dogs, foxes, or bobcats, opossums sometimes flop onto their sides and lie on the ground with their eyes closed or staring fixedly into space. They extend their tongues and generally appear to be dead. This ploy may put a predator off its guard and allow the opossum an opportunity to make its escape. Plus, Opossums are excellent tree climbers and spend much of their time aloft. They are aided in this by sharp claws, which dig into bark, and by a long prehensile (gripping) tail that can be used as an extra limb. Opossums nest in tree holes or in dens made by other animals.
Habitat : They live in mainly North America and Canada. To be specific, opossums are found in forest, farmland, grassland, urban and suburban areas, near water.
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Additional reproductive, physiological facts
Opossums has some special traits comparing to general mammals. To explain briefly, first, the arrangement of 'yolk' in the oocyte cytoplasm. Second, the time of formation of cortical granules and the mode of sperm penetration through the zone pellucida. Third, the sperm membrane involved in sperm-egg fusion, Fourth the fate of inner acrosomal and sperm plasma membranes. Lastlly, the rapidity of sperm chromatin decondensation in the ooplasm.
Early in embryologic development have paired invagina. Female opossum has 2 vagina that preventing urine not from fusing together during development of pouch. Neither of the vaginae functions as a birth canal. Instead, new opening form of connective tissue lies between the vagina. This special pseudovaginal canal develops at the reproductive delivery time and disappears after that. Deep well defined pouch functions as living incubator in which to maintain her young baby during first 75 days to 80 days.
Opossums has some special traits comparing to general mammals. To explain briefly, first, the arrangement of 'yolk' in the oocyte cytoplasm. Second, the time of formation of cortical granules and the mode of sperm penetration through the zone pellucida. Third, the sperm membrane involved in sperm-egg fusion, Fourth the fate of inner acrosomal and sperm plasma membranes. Lastlly, the rapidity of sperm chromatin decondensation in the ooplasm.
Early in embryologic development have paired invagina. Female opossum has 2 vagina that preventing urine not from fusing together during development of pouch. Neither of the vaginae functions as a birth canal. Instead, new opening form of connective tissue lies between the vagina. This special pseudovaginal canal develops at the reproductive delivery time and disappears after that. Deep well defined pouch functions as living incubator in which to maintain her young baby during first 75 days to 80 days.
Fertilization Mechanisms
The fertile estrus period of the opossum is 12 hours in duration or more. Following ovulation and mating, the paired sperm separate in the oviduct. With the seperation of the sperm pair, the acrosome of each sperm swells and is filled with small membranous vacuoles. Just prior to fertilization the acrosomal surface of a sperm comes to lie flat on the zona pellucida surrounding the ovum. The hydrolytic enzymes contained within the acrosome are then released and digest a relatively large, uneven hole in the zona pellucida. The acrosomal surface of the sperm head then fuses with the cell membrance of the ovum. Fertilization is monospermic. Granules called cortical granules, concentrated in the peripheral margin of the opossum ovum interestingly disappear at fertilization. The release of the cortical granules is an absence of egg and sperm membrances around the decondensing sperm head soon after its incorporation into the ovum. This patter on gamete interaction more closely resembles that of non-mammalian vertebrates and intervertebrates than eutherian mammals. The second polar body, containing excess genetic material is shed by oocyte following the incorporation of the single spermatozoon. Following cortical granule mentioned above, release by fertilized ova, the oocytes are covered by thick oviductal mucus. Thus this ferilized oocytes now referred to as zygotes reach the uterus between 12 and 24 hours after ovulation.
The fertile estrus period of the opossum is 12 hours in duration or more. Following ovulation and mating, the paired sperm separate in the oviduct. With the seperation of the sperm pair, the acrosome of each sperm swells and is filled with small membranous vacuoles. Just prior to fertilization the acrosomal surface of a sperm comes to lie flat on the zona pellucida surrounding the ovum. The hydrolytic enzymes contained within the acrosome are then released and digest a relatively large, uneven hole in the zona pellucida. The acrosomal surface of the sperm head then fuses with the cell membrance of the ovum. Fertilization is monospermic. Granules called cortical granules, concentrated in the peripheral margin of the opossum ovum interestingly disappear at fertilization. The release of the cortical granules is an absence of egg and sperm membrances around the decondensing sperm head soon after its incorporation into the ovum. This patter on gamete interaction more closely resembles that of non-mammalian vertebrates and intervertebrates than eutherian mammals. The second polar body, containing excess genetic material is shed by oocyte following the incorporation of the single spermatozoon. Following cortical granule mentioned above, release by fertilized ova, the oocytes are covered by thick oviductal mucus. Thus this ferilized oocytes now referred to as zygotes reach the uterus between 12 and 24 hours after ovulation.
Defense Mechanisms
There are several defense action when the opossum confronts danger. First, The opossum has involuntary comatose like state induced by extreme fear. They pretend to be killed to be left alone by predators. Second method is drooling, an Opossum work its jaw until excessive drool forms and it is actually blowing bubbles out of its nose. Third one is Anal gland flud, which cause release of a green color anal fluid out of the body.
There are several defense action when the opossum confronts danger. First, The opossum has involuntary comatose like state induced by extreme fear. They pretend to be killed to be left alone by predators. Second method is drooling, an Opossum work its jaw until excessive drool forms and it is actually blowing bubbles out of its nose. Third one is Anal gland flud, which cause release of a green color anal fluid out of the body.