Original photo by Andrew Haysom/ iStock
A baby red kangaroo (Macropus rufus) is about the size of a jelly bean. Born after about 34 days of gestation, it’s less than an inch long — or 100,000 times smaller than its adult height (roughly 4 feet). This newborn kangaroo, called a joey, isn’t quite ready for prime time, however. Unlike most mammals, joeys are born while they’re still embryos, which means they lack sight, hearing, and hair. They spend the next six months in their mother’s pouch, or marsupium, where they suckle from a teat and continue to develop before finally taking their first steps into the world. If the word “marsupium” sounds familiar, it’s probably because that’s where the term “marsupial” comes from. Marsupials are a mammalian class that includes kangaroos, wombats, koalas, possums, and more — about 330 species altogether.
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It's a factCats don’t have a monopoly on the “kitten” term. Baby rabbits are also called kittens, while the animal’s short birthing process is called kindling. Rabbits can have multiple litters a year, with up to 12 kittens in each (though the average is five).
Kangaroos are some of the supermoms of the animal kingdom. Not only do they have a special pouch for their babies, but they can create two distinct types of milk to care for both the developing embryo and the more mature joey. They can even suspend their ability to conceive during times of drought, and then regain that ability when conditions are more favorable. With their remarkable adaptability, it’s no wonder kangaroos outnumber Australians nearly two to one.
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A group of kangaroos is known as a ______.
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A group of kangaroos is known as a mob.
Most kangaroos are left-handed.
Turns out, a kangaroo paw is also a southpaw. A 2015 study of wild eastern gray kangaroos, red kangaroos, and red-necked wallabies found that they preferred their left hand for grooming, eating, and performing other tasks about 95% of the time. This stunning discovery goes against the long-standing theory that only humans (and some apes) have a strong preference for one hand over the other; 90% of humans are right-handed. Scientists think this is likely a case of “parallel evolution,” in which animals in different branches of the evolutionary tree develop similar traits through separate processes.
Darren Orf lives in Portland, has a cat, and writes about all things science and climate. You can find his previous work at Popular Mechanics, Inverse, Gizmodo, and Paste, among others.
