Placental, Marsupials, And Monotremes

There are 3 different ways mammals give birth: Placental, Marsupials, and Monotremes. Even though mammals give birth different ways they are still classified as mammals. To be classified as a mammal you need to be a vertebrate, have warm blood, body hair or fur, breathe using lungs, and give milk to their young for nourishment. But the three ways they give birth makes them very different with multiple species included in each kind. Also, the ways they keep and nurse their young varies with the species also. The most known kind of way mammals give birth are placental. Placental mammals make up about 5000 different mammals. This includes humans, dogs, horses, dolphins, and the blue whale. To be a placental mammal you need a placenta: a blood-rich tissue that connects to the umbilical cord. Placental mammals also give birth to their young alive and not needing to develop anymore. Some species of placental mammals give birth to mammals that are able to walk, swim, and run right after birth. But all placental mammals have to nurse off of their mother until they are able to
eat food. Placental mammals are also in the womb longer than other mammals and the have a period of rapid and continuous growth and eating like all other mammals. The second kind of way mammals give birth are marsupial.
Marsupials are native to Australia, South America, and North America. Marsupials include kangaroos, quoll, possum, and wombats. Marsupials are different than placental mammals because they spend less time in their mother’s womb and finish developing in their mother’s pouch. When born marsupials are extremely tiny and delicate. They crawl to their mother's pouch and finish developing in there by getting milk. Marsupials also come back when they are out of their mother’s pouch to still get milk for growth. Some marsupials can support 3 babies at one time by having an embryo, one small baby in her pouch, and one that is big enough to be out of the pouch but still needs milk. Some species of marsupials have backward pouches so when they dig no dirt gets into it. Marsupials can range in size but they are closer in size than placental
mammals. Monotremes are mammals that lay eggs instead of giving birth to an alive young. Monotremes are only made up of 5 different mammals, 4 species of echidna, and the duck-billed platypus. Monotremes also don’t feed on their mother the same way placental and marsupials do, monotremes drink milk from pores on their mother’s skin. Once monotremes are big enough they stop getting milk from their mother and eat food on their own. The eggs monotremes lay are soft-shelled, small, and look like bird eggs. Monotremes also mainly native to Australia and the surrounding islands. All monotremes have defensive adaptations to their body. Echidnas have sharp hair in their body like a porcupine and platypi have a venomous spur on their feet. Monotremes make up the smallest class of Mammalia but are the weirdest. Mammals give birth many different ways. The ways mammals give birth may make the species sound like it is not a mammal but they are still included in the species all the same. Since mammals give birth differently that allows for a species to survive, reproduce, and survive extinction.