Mammals are the most developed animals of all vertebrates , they are known to be warm-blooded, have their bodies covered in hair, and they breastfeed their cubs. However, not all of this class have the same properties. In fact, we can divide them into placentals and marsupials . Let’s see then 4 differences between placental mammals and marsupials that will help you understand such an important group of the animal kingdom .
1. Placenta verses marsupia
The fundamental distinction between placental mammals and marsupial mammals is precisely the way in which gestation occurs in females. In placentals, the creatures develop inside the mother’s body, in a sac called the placenta – hence its name – which provides the embryo with oxygen and all the nutrients necessary for its formation.
The young are born in advanced stages and are stronger against the environment. In marsupials, on the other hand, the little ones pass into a bag, called a marsupia , where they finish their formation. They are too weak to deal with the environment, so they need to stay within their “lair” until their development is complete.
2 . Reproductive organs in placental and marsupial mammals
The female placentals have a single vagina , which is used to perform copulation and later as a conduit for the birth of the puppy. In contrast, female marsupials have two vaginas
Both open to the same external hole, but lead to two different spaces within the uterus . Placental males have a penis that is inserted into their partner’s vagina during intercourse. Marsupials have a double-headed penis, which corresponds to the two female vaginas.
3. Waste disposal process
Placental mammals and marsupials also have different ways of removing waste from their bodies. The former have a hole to defecate and urine is produced through the penis.
In marsupials, on the other hand, the penis is only a sperm conduit for fertilization . Both sexes have a hole called the cloaca , which joins the urogenital sac , where waste accumulates and is later expelled.
4. How do they breastfeed your young?
We already said that a characteristic that unifies mammals is that they breastfeed their young . However, both types of animals do it in different ways. The placental female has nipples that lead to the mammary glands , from where the milk comes out that the little ones will suck. Marsupials, always so rare, do not have nipples, but the young stimulate milk production and the liquid is secreted through pores. The puppies lick the milk.
We have seen that although both belong to the class of mammals , there are differences between placental and marsupial mammals . These adaptations are related to the different environments where these groups of animals developed during the evolutionary process .