Agile Wallaby (Macropus agilis) x
In the wild, kangaroos and wallabies do not mate with each other. Humans have attempted to interbreed the two, but the results have been unsuccessful.
Several macropod hybrids have been experimentally bred, including: Eastern Wallaroo (Macropus robustus) X Red Kangaroo (Macropus rufus).
Although physically more like kangaroos, wallaroos' genetic make-up is closer to that of some wallabies and can cross-breed with some wallaby species.
When two different species successfully mate, the resulting offspring is called a hybrid. Hybrids are often, but not always, sterile (think of mules). Hybrids aren't necessarily good news for a rare or threatened species.
Even if you found a cat-sized kangaroo, a cat is a placental and a kangaroo is a marsupial. They simply could not hybridise.
Kangaroos are infected with toxoplasmosis following exposure to contaminated feline feces. Cats are the definitive host for T. gondii and will shed large amounts of this parasite in the environment. Though not always practical, limiting access of cats to kangaroo pens is important for disease prevention.
Male kalutas, small mouselike marsupials found in the arid regions of Northwestern Australia, are semelparous, meaning that shortly after they mate, they drop dead. This extreme reproductive strategy is rare among vertebrates —only a few dozen are known to reproduce in this fashion, and most of them are fish.
In the wild, it is unlikely that the twins would be able to survive. When joeys reach around three kilos, they are still living in mum's pouch, so six kilos might be a bit too much to handle. "Sometimes they will toss one away, or just keep the stronger one if they find that it's too much," explains Mandy.
Almost all kangaroos and wallabies have two separate uteruses, and they usually contrive to have extra, undeveloped embryos waiting in the wings — or rather, in whichever uterus was unused in their most recent pregnancy.
Intersexuality also has shown up in baboons, deer, moose, buffalo and kangaroos. No one is sure why. But in at least some instances, water pollutants — such as pesticides — have led to clearly abnormal conditions.
“It is rare to see a kangaroo or wallaby with twins, and in the wild the survival rate for twins would be very low,” he said. “As joeys develop there is not much room in the pouch, which is why usually only one is suckled at a time.
Young wallabies, like their larger kangaroo cousins, are called joeys. Even after a joey leaves the pouch, it often returns to jump in when danger approaches.
Nope! The Wallaby is a small marsupial, much smaller than its big Kangaroo sister. One of the biggest characteristics of the wallaby that separates them from kangaroos is size. Wallabies usually only grow to about 3 feet tall and weigh around 45 pounds.
Standing up to dogs
Other than humans, dogs – including large pets and dingoes – are the main predators of kangaroos. Dogs usually operate in packs to attack and kill kangaroos by running them down.
Kangaroos have few natural predators: Dingoes , humans, Wedge-tailed Eagles and, before their extermination, Tasmanian Tigers . Introduced carnivores, such as wild dogs and foxes prey on the young, and introduced herbivores compete with kangaroos for food.
The dingo and wedge-tailed eagle are the natural enemies of the kangaroo. But humans are also an enemy of the kangaroo.
And they do exist—mules, for instance, are the result of a horse and donkey mating. But creating hybrids of animals that are very genetically distinct from each other—such as a dog and a cat—is scientifically impossible, as is one species giving birth to an entirely different one.
Female kangaroos are quite the impressive mothers and can raise three joeys simultaneously. They can support one on foot, that is to say out of the pouch but still needing milk, one in the pouch, and one in the womb. During this time, she can produce three unique kids of milk to suit the needs of each joey – cool!
Ethical considerations preclude definitive research on the subject, but it's safe to say that human DNA has become so different from that of other animals that interbreeding would likely be impossible.
There are documented cases of Soviet experiments in the 1920s where artificial insemination was attempted using female chimps and human sperm. However, none of these experiments resulted in a pregnancy, much less the birth of a 'humanzee'.
In fact, such human-animal hybrids are often referred to as “chimeras”. While this scientific advance offers the prospect of growing human organs inside animals for use in transplants, it can also leave some people with a queasy feeling.