What is the Difference Between Placental and Marsupial?

The main difference between placental and marsupial mammals lies in their reproductive systems and the way they nurture their offspring. Here are the key differences:

1. Placenta: Placental mammals have an internal placenta, an organ that attaches to the growing embryos and provides them with oxygen and nutrients during pregnancy. Marsupials, on the other hand, have no internal placenta, and their offspring absorb nutrients from the yolk of their ovum.
2. Gestation: Marsupials have a brief gestation period compared to placental mammals. Young placentals experience a tremendous amount of in utero growth and development, while marsupial offspring are born in a less developed state.
3. Lactation: Marsupials compensate for the lack of a placenta by providing an extended lactation period during which the offspring suckle on their mother's nipples. Placental mammals, in contrast, have a more limited lactation period.
4. Reproductive Anatomy: Female marsupials have two fully developed sets of reproductive structures, including two vaginae, two cervices, two uteri, and two fallopian tubes. In contrast, female placentals have only one of each of these organs.

Despite these differences, both marsupials and placentals are considered placental mammals, and they share some similarities in their reproductive systems.

Comparative Table: Placental vs Marsupial

Here is a table comparing the differences between placental and marsupial mammals:

Placental mammals, such as humans, elephants, and dolphins, have a developed placenta that provides nutrients and oxygen to the fetus during gestation. They give birth to fully-developed live young with a longer gestation period. On the other hand, marsupial mammals, like kangaroos and koalas, have a yolk sac placenta and give birth to underdeveloped live young that require further development in an external pouch.