Marsupial

Marsupial

A Marsupial is a type of mammal characterized by giving birth to relatively undeveloped young. They are part of the Infraclass Marsupialia, which is further divided into seven orders.

Characteristics

Marsupials have a unique reproductive system in which the female has two uteruses, unlike placental mammals which have one. The young, often called a joey, is born at a very early stage of development and crawls out of the uterus and into the mother's pouch. There, it latches onto a nipple and continues to develop.

Distribution and Diversity

Marsupials are found primarily in Australia and New Guinea, but also in America, particularly South America. They range in size from tiny shrew-like species to the large kangaroos and wallabies. The most well-known marsupials include the koala, wombat, and Tasmanian devil.

Evolution

The exact evolutionary history of marsupials is still a subject of debate among scientists. However, it is generally agreed that marsupials originated in South America and then spread to other parts of the world.

See also

• Monotreme
• Placental mammal

References

<references />

External links

• Marsupial at Encyclopædia Britannica

• 
  Marsupialia
• 
  Koala climbing tree
• 
  Sugar Glider Cincinnati Zoo
• 
  Kangaroo and joey
• 
  The cyclopædia of anatomy and physiology (1847)
• 
  Cambridge Natural History Mammalia Fig 048
• 
  Jeune M. rufogriseus poche
• 
  A hand-book to the marsupialia and monotremata (Plate XXXII)
• 
  Phylogenetic tree of marsupials derived from retroposon data (Paucituberculata)
• 
  Phylogenetic tree of marsupials derived from retroposon data (Microbiotheria)
• 
  A monograph of the Macropodidæ, or family of kangaroos