Folks, we’re heading back to Australia this week on the blog.
Australia: the place where evolution went wild.
The place where it went wild and created one of the cutest animals ever: the quokka!
This smiling little creature is a quokka (pronounced KWAH-kuh; Setonix brachyurus). Quokkas are about the size of a domestic cat and look kind of like giant rats. In fact, the Dutch explorer Willem de Vlamingh thought quokkas were giant rats, so he named one of the islands you can find quokkas on ‘Rottenest,’ or ‘Rat’s Nest.’
Today, you mainly find quokkas on two islands off the coast of southwestern Australia: Rottnest Island and Bald Island. A small population does live on the mainland, but they’re under threat from predation by feral cats and foxes.
Tiny little wallaby
The quokka is one of the smallest types of wallaby. Like all wallabies, it’s part of the family Macropodidae, which includes kangaroos. Quokkas are the only species in their genus Setonix.
What exactly is the difference between a wallaby and a kangaroo? The easiest way to tell these animals apart is by their size: kangaroos can grow 8 feet tall, while wallabies rarely grow more than 3.2 feet. Kangaroos also have longer legs than the compact legs of wallabies. These long legs help kangaroos move fast across open terrain, while a wallaby’s legs are great for hopping through a forest.
Both kangaroos and wallabies are a type of mammal known as a ‘marsupial,’ or pouched mammal. (Note: not all marsupials have pouches! Some have just a fold). Marsupials give birth after a very short gestation time, after which the helpless baby crawls from the birth canal to its mother’s nipples. These nipples are in a pouch on the mother’s body, and it’s within this pouch that the young marsupial will continue to develop.
Like the young of other marsupials, baby quokkas are called ‘joeys.’ Joeys are ‘born’ after just 27 days. They then move into their mother’s pouch, where they will live for the next six months.
While this joey is developing, the mother quokka creates a backup. She will mate again just one day after giving birth. This embryo will stay in her womb in a suspended state of development for five months. If the original joey is still alive, this embryo will dissolve; if the original joey died, the embryo would get to move into the pouch.
Why might a joey die? There are all the classic reasons infants die – getting sick, not having enough food, etc. But there’s another reason: their mom might sacrifice them. When attacked by a predator, quokka mothers (and kangaroo and wallaby mothers) relax the muscles surrounding their pouch so that the joey falls out. The joey then squirms and makes noise, distracting the predator so the mother can escape.
This might seem harsh but remember: animals are trying to have as many offspring throughout their life as possible. Evolutionarily, it makes sense for a mother quokka to sacrifice one joey so that she can live to have many more later.
Need little water
There’s not a lot of water on Rottnest Island, so it’s good that quokkas can survive on very little. They can go an entire month without drinking water; to stay hydrated, they rely on getting moisture from plants.
But to be clear, quokkas do still need water, and it serves as a limiting factor for their population. They need to be close to fresh water when possible, and groups will often form around freshwater soaks (underground water that bubbles up to the surface).
Chewing their cud
Quokkas are ruminants – they will swallow their food without chewing it, just to regurgitate it as cud for later chewing. Cows are also ruminants! However, whereas cows have a special stomach compartment called a rumen, quokkas do not. Their stomach anatomy is much less specialized than ruminants like cows and sheep, which suggests they are less specialized for rumination.
When food is scarce, quokkas will bypass eating entirely. Instead, they’ll draw on fat stores in their tails for energy as a short-term solution for a lack of plants to eat. Quokkas can also climb about 5 feet up a tree to grab some tasty vegetation.
Quokkas seem to always be smiling 🙂 Of course, they’re not actually smiling; this is just how their face looks because of their facial muscles and front teeth.
This ‘smile’ is paired with a very friendly and curious personality. Quokkas seem to have little fear of humans, and they will get quite close to tourists on Rottnest Island. There’s even a trend of getting #QuokkaSelfies on Instagram.
In general, you shouldn’t get that close to wild animals – they could bite or be distressed from close contact with humans (and remember that being stressed could lead to them throwing their joeys from their pouch!). However, the quokkas on Rottnest Island don’t seem distressed and are free to move away from tourists when they wish. The most humane way to get that quokka selfie is to let them come to you and never touch them!
If and when I go to Australia, I’m definitely stopping by Rottnest Island to try to see these cuties!
The Nature Conservancy – Australia
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