What Is The Difference Between A Marsupial And A Placental?

Marsupials and Placentals are mammals, and while many people might not realize the differences at first, there are quite a few differences that help set these two groups of mammals apart. 

When it comes to identifying whether or not an animal is a placental or a marsupial, it is incredibly easy to tell, and once you know what the differences between these two types of mammals are, you will soon be able to know which is which in no time at all. 

What Is The Difference Between A Marsupial And A Placental?

So, if you want to learn more about the differences between a marsupial and a placental mammal, then read through our guide to learn all of the information you need to know about both marsupial mammals and placental mammals! 

What Are Placental And Marsupial Mammals?

Initially, it might be slightly confusing when it comes to trying to figure out which animals in the animal kingdom are placental, and which are marsupials.

However, when you consider the name “placental” a little bit, the initial difference might become a little clearer. 

Placentals are the most common type of mammal in the animal kingdom, and include dogs, cats, mice, cows, whales, and most importantly, us humans too!

There are well over 5,000 types of placental mammals on the planet, and they inhabit every continent on Earth outside of Antarctica. 

In contrast to this, however, there are way fewer marsupials in the world, in fact, there are less than 300 known species of marsupial mammals on the planet, which tend to make their homes in places such as Central and South America, as well as Australia.

These include animals such as Wombats, Koalas, Opossums, Kangaroos, and Tasmanian Devils. There is just one marsupial mammal that can be found in North America, and that is the Virginia Opossum. 

The Differences Between Placental And Marsupial Mammals

So, now that you’re more aware of what sort of animals make up each group of these subcategories of mammals, then chances are that you’ll at least realize what the biggest difference between these two groups is, if not, then allow us to explain further: 

The Biggest Difference

The biggest difference between these two groups of mammals is arguably a Marsupial’s defining feature, and that is that the females will actually have a pouch. 

It’s worth noting that not ALL Marsupials have a pouch, but for the most part, they do, but it goes much further than this too because there is actually some variance in the types of pouches that a female marsupial can have too.

These pouches have a few differences between them too, such as their size, as well as the strength of their pouch.

In addition to this, not all marsupials have a permanent pouch on their bodies, as some marsupials only gain this pouch once they begin to undergo their reproductive cycle. 

So, rather than have a placenta to provide everything their offspring need whilst they develop, a Marsupial’s pouch provides both safety and nourishment for their young, especially as a Marsupial’s nipples can be found in the pouch, so the young aren’t exposed and can have constant access to the mother’s milk. 



Aside from the pouch, Marsupials actually have more teeth than a placental animal does too, but the type of teeth that they have is entirely dependent on the species.

For example, some marsupials, such as Opossums and Common Wombats only have two incisors, which are located on their lower jaw.

In contrast, placental mammals, and other marsupials, typically have four incisors, two on the lower jaw and two on the upper jaw. 

Marsupials can only usually replace certain teeth too, whereas most placental animals are known to have two sets of teeth, one set is known as the “baby teeth” and the other is then known as the “adult teeth”, which replace the first set of teeth entirely as the animal matures. 

Reproductive Anatomy

For the most part, the males of both marsupials and placentals don’t tend to differ from one another all too much. However, this is certainly not the case for females. 

Female marsupials have two fully developed reproductive systems. So that means that they have two vaginae, two cervixes, two uteri, as well as two fallopian tubes.

On the other hand, apart from the two fallopian tubes, placentals only have one of each of these. 

The vaginae of a marsupial are placed on either side of its ureter, and both of them are completely able to be fertilized, but they fuse together once the marsupial is ready to give birth, which then leads to the formation of what is known as the “median vagina”.

Once a marsupial has given birth once, this will reform until the next time, except for in some species where it remains open permanently. 


Marsupials tend to gestate for a lot shorter period of time in comparison to placentals, and the young of placentals experience a lot of growth during their time in the uterus, which is why they tend to resemble their parents’ appearance and capabilities as soon as they are born (except for humans). 

On the other hand, much of a marsupials development comes after its birth, where they are nourished and protected inside their mother’s pouch in order for them to develop, and as the milk she produces changes as their young develops, it ensures that all of the nutrients and nourishment they need is delivered properly and consistently to ensure that they grow and develop as they need to. 


To summarize, there are some stark differences between marsupials and placental animals, including their anatomy, teeth, as well as their differing reproductive system and gestation periods.

After learning about what some of these differences are, it should now be incredibly easy to understand which animals are marsupials and which animals are placentals. Visit this Guide To Know Animals That Aren’t Mammals if you’d like to learn more.

Olivia Kepner