What is a marsupial?
While the main difference between marsupials and placental mammals is often thought to be the presence of a pouch not all species have a pouch. The word marsupial comes from a Latin word 'marsupium' meaning pouch.
Instead the key characteristic setting them apart from other marsupials is they give birth to underdeveloped young which develop externally. Most develop in a pouch but others lack this.
The longest gestation of any marsupial is the long-nosed potoroo with their young developing for 38 days before they move to the pouch to complete their growth.
Most female marsupials have two uteruses and two vaginas. Males then have a two-headed penis so they can mate with females.
Depending on your source there are between 250 and 330 species of marsupial.
Record Breaking Marsupials
The largest marsupial which is currently alive is the red kangaroo which can grow up to 2.1m (6.9ft) tall.
Meanwhile the smallest is the long-tailed planigale. These mini marsupials measure just 12 cm (4.7 inches) long.
Previously a marsupial known as the diprotodon which was related to the modern day wombat but was around the size of a rhinoceros roamed Australia. This species is now extinct.
More on Marsupials
Marsupials are the only other mammal group outside the primates which have developed opposable digits. Many tree climbing species have retained this to help them climb.
In comparison to placental mammals, the marsupials also have a slower metabolism and a smaller brain.
Marsupial Fact Files
Augustyn, A., 2020. Marsupial – Paleontology And Recent History. [online] Encyclopedia Britannica. Available at: <https://www.britannica.com/animal/marsupial/Paleontology-and-recent-history> [Accessed 27 December 2020].\
Ucmp.berkeley.edu. 2020. Marsupial Mammals. [online] Available at: <https://ucmp.berkeley.edu/mammal/marsupial/marsupial.html> [Accessed 27 December 2020].
CSIROscope. 2020. Quick Facts About Marsupials – Csiroscope. [online] Available at: <https://blog.csiro.au/quick-facts-marsupials/comment-page-2/#comments> [Accessed 27 December 2020].
Burnie, D., 2011. Animal. 3rd ed. London: DK
Slater, P. and Parish, S., 2016. First Field Guide To Australian Mammals. 1st ed. New South Wales: Pascal Press.