Modern humans originated in Africa, some 200,000 years ago, and evolved from their most recent ancestor, Homo erectus, which means ‘upright man’ in Latin.
Homo erectus is now an extinct species that lived from 1.9 million years ago up to around 135,000 years ago.
However, despite lots of different studies and experiments, there is still some confusion as to which species humans belong to. So, are humans marsupials?
In this post, we’ll address some widespread misconceptions and break down the differences between these two groups.
Are Humans Marsupials?
No, humans are not marsupials. They belong to a group of mammals of the order Primates, together with other animals like lemurs, lorises, tarsiers, monkeys, and apes.
Humans are the most widespread species of primates that walk on two feet (bipedalism) and have large, complex brains.
Humans are not considered marsupials since they do not carry their newborns in a pouch as most marsupials do. Also, unlike most marsupials, humans give birth to a fully developed baby.
Humans (Homo Sapiens) are one of over 300 species that belong to the order Primates, the third most diverse order of mammals, after rodents and bats.
On the other hand, marsupials are animals that belong to the group called Marsupialia. Humans are not part of this group of animals.
What Are Marsupials?
Marsupials are mammals that give birth to an altricial young to be nursed inside a pouch. Altrical youngs are born prematurely in an undeveloped state, and continue their development while attached to the nipples on the mother’s lower belly.
Humans are definitely not one of those animals!
The pouch – or marsupium, from which the group got its name – is a flap of skin covering the nipples.
Wombats and marsupial moles, species of burrowing marsupials, have backward-facing pouches so the dirt doesn’t get in as the animals dig. The pouch of a female koala opens to the side, while in water opossums both females and males have pouches.
Almost 70% of marsupials can be found in Australia and New Guinea; the rest are distributed throughout North, Central, and South America.
Some larger species of marsupials are the kangaroos, koalas, wombats, and wallabies, while the smaller ones include opossums, Tasmanian devils, and bandicoots.
The largest marsupial in the world is the red kangaroo, weighing up to 200 pounds – the baby kangaroo, called a joey, is just an inch long at birth and weighs only 0.035 oz!
Marsupials first evolved in South America about 100 million years ago, when South America, Australia, and Antarctica were a single continent.
Why Are Humans Not Marsupials?
Humans are not marsupials because they belong to a different infraclass of animals.
There are three types of mammals based on the way they reproduce: monotremes (mammals that lay eggs), marsupials (mammals that give birth to an early-stage fetus), and placentals (mammals that give birth to fully developed fetus).
Marsupials belong to an infraclass called Marsupialia, where the newborns are incompletely developed and are typically carried and suckled in a pouch on the mother’s belly.
For example, the red kangaroo is born after only about one month of pregnancy. At this stage in development, the newborn is hairless, has closed eyes, and has undeveloped back legs.
After that, this bean-sized animal has to climb into the pouch and latch on one of four nipples. It will remain there for about 8 months before it leaves the pouch and starts feeding on its own.
Unlike marsupials, humans have a placenta and do not carry their babies in a pouch.
Humans are not members of that infraclass.
Are Humans Placental Mammals?
Yes, humans are placental mammals. The eutherian or “placental” mammals, like humans, make up the biggest part of the mammalian group and include nearly 4000 species.
Humans belong to the infraclass Placentalia, in which a placenta develops during pregnancy.
The placenta provides oxygen and nutrients to a growing baby, removes waste products from the baby’s blood, and protects it while it grows inside the uterus.
The placenta attaches to the wall of the uterus, and the baby’s umbilical cord arises from it.
After the baby is born, the umbilical cord is no longer needed and gets clamped and snipped.
After the umbilical cord – through which the mammalian fetus receives nourishment – is removed, humans will have a scar on their stomach. This is known as the belly button or a navel.
Unlike humans and other placental mammals, marsupials will not have a belly button scar.
Humans, dogs, rabbits, elephants, lions, tigers, bears, lemurs, and many other animals are placental mammals. Nearly 95% of all modern mammals species belong to this group.
It should be noted that not all marsupials have a pouch. Some have exposed teats, while others will develop a pouch only during pregnancy.
And as we mentioned before, marsupials are most diverse in Australia and New Guinea, where there are no placental mammals. That allowed them to thrive there and diversify into a variety of different species.
In places where marsupials and placental mammals developed alongside one another, placental mammals took over and were the dominant ones.
Still, these groups are closely related. According to genetic studies, some 180 million years ago, marsupials diverged from placental mammals, during the Jurassic Period.
Marsupials are notably less intelligent than other placental mammals, partly because of their simpler brains.
Final Thoughts – Are Humans Marsupials?
In conclusion, humans are not marsupials. They are animals that belong to the order of placental mammals called Primates.
Primates can be split into two groups: strepsirrhines (‘twisted-nostriled’) and haplorhines (‘simple-noses’).
Strepsirrhines include lemurs, galagos, and lorisids.
Haplorhines include tarsiers and the simians (apes and monkeys).
Simians, or snub-nosed, are split into platyrrhines (flat-nosed) and catarrhines (narrow-nosed). Flat-nosed animals are the New World monkeys, while the narrow-nosed ones are the Old World monkeys and apes (including humans).
The main difference between humans and marsupials is that the humans are placental mammals that do not give birth to an undeveloped baby and do not keep it in their pouches, as marsupials do.
If you were pondering on the question “are humans marsupials”, we hope this article removed all doubts.
And if you enjoyed it, here are two recommendations on other very popular reads:
Do rabbits belong to the marsupial group of animals? | Do pigs give live birth or do they reproduce by laying eggs?