Marsupial Reproduction :: Marsupials Reproduction Mammals Biolgoy Essays

Marsupial Reproduction Knowledge can be obtained and conveyed in a variety of ways. One can spend hours upon hours hidden away in the corner of a library, reading the thoughts and discoveries of other researchers and writers. Or, one can allow himself to make his own discoveries through experiments and observations that he makes himself. Both methods are necessary in order to come to a complete understanding of a topic. An experimenter cannot fully appreciate the things that she observes without having a background in that area. In the same way, a man does not truly use the knowledge he has gained from book research without applying it to the real world in some way. Knowledge of marsupial reproduction is this way. There is much to be learned from the writings of scientists of the past, while at the same time there are many new discoveries to be made as researchers of the present apply this knowledge to answering new questions. The purpose of this paper is to compile knowledge that has already been written on marsupial reproduction, including the topics of: marsupial characteristics, reproductive anatomy, sexual behavior, development of young, hormonal control, and ecological implications of reproductive patterns, so that it can be used as a basis for new insights and discoveries. What is a marsupial? Many biologists of the past and present have been intrigued by a group of animals known as marsupials. Marsupials are a subdivision of mammals with several defining characteristics. First, marsupials generally have more incisor teeth than eutherian (placental) mammals. In most marsupials, as in most primates, the first toe of the hind foot is opposable to the other four, and it always lacks a claw. Interestingly, most terrestrial marsupials have lost this toe altogether. Marsupials also tend to have a smaller brain than eutherians of equivalent size and their body temperature and rate of metabolism are slightly lower than eutherians. (Gould, 52) Other important characteristics of marsupials come from their unique reproductive patterns and reproductive system. Externally, differences include à ¬such interesting anatomical features as a prepenal scrotum and biparte penes and vaginae in most groups and typically, but not always, a pouch over the teats.à ® (Bronson, 187) The major difference is the dramatically abbreviated period of gestation marsupials have adopted and the function of this phenomenon. Few marsupials have a gestation period longer than their oestrous cycle. This means that all marsupials give birth to highly altrical