Marsupials, commonly known as pouch animals, have a slow metabolism which works well within the warm climates of Australia and South America. Some scientists believe this is the reasoning behind their living location. Of course, there are other locations on earth with warm climates where marsupials do not exist. In order to understand why marsupials live primarily in Australia and South America we must take a look at history.
Fossils of the earliest marsupial, Sinodelphys szalavi, were found in China and believed to be 125 million years old. However, scientists believe marsupials first developed in North America and then dividing into Europe, on to Asia , Africa and South America. They would have gone onto Australia from South America while land masses were still connected. Yet another theory believes that marsupials actually developed in Australia then traveling to Antarctica and South America to North America. Yet the fossils in China may indicate the marsupials started in Asia and migrated on to Australia. There are several scientific theories as to how and why marsupials ended up in Australia and South America, but the truth is, no one actually knows for sure.
During the Mesozoic era marsupials were quite common in North America, however, today the opossum is the only one. Currently these pouched animals flourish in Australia while in South America they began to decline during the Miocene and Pilocene eras, leaving only the rat opossum group today. Science have found that many placenta animals parallel marsupials through out history, such as wolves and lions.
What are Marsupials
Although, marsupials are generally thought of as animals that carry their young in pouches, some do not have a permanent pouch and some do not have a pouch at all. With these the underdeveloped young merely attach to the mother’s teat and develop out in the open. For the majority of marsupials with pouches, the young are born undeveloped and then climb with their clawed forelimbs up and into the mother’s pouch. There they attach themselves to a teat and continue to develop.
There are 140 species of marsupials in Australia and New Guinea (which was once connected to Australia), the largest being the Red Kangaroo which can reach six feet. The smallest is a shrew-like animal called ningauis that can weigh less than 1/10th of an ounce. Besides kangaroo species in various sizes they also include bandicoots, koalas, tasmanian devils and wombats. there are even four legged moles called notoryctes. There was a marsupial wolf, thylacinus, last seen in Tasmania and now extinct since 1950.
Marsupials in the News
Recently researchers have used computer simulation to suggest an ice age marsupial lion had a form of killing it’s prey by slicing and dicing. The lion apparently had a set of teeth resembling bolt cutter. Their research implicates that he used these teeth to scissor through the neck area, cutting through the windpipe and arteries, of other animals. Scientists imply it would have taken a very short time for the kill, just minutes. Today’s lions kill by asphyxiation. With a larger animal the actual death could take up to 10 to 15 minutes. This marsupial lion was extremely efficient and quick in taking his prey.
Another ice age marsupial that resembled the wombat has been found to weigh three tons according to experimental estimates. He developed during the Pleistocene era, between two million to ten thousand years ago. They believe the animal became completely extinct shortly after humans colonized Australia, about forty thousand years ago.