The Opossum: How Did This Marsupial Ended Up In North American
There are probably a lot of people who are unaware that our nocturnal friend, the opossum, is a marsupial. Yep, they are in the same class of mammals as the kangaroos and many other Australia mammals. They belong to the infraclass of mammals called Marsupialia, where the females have a pouch to carry their young until they reach maturity. Some people believe they are in the same family as the rat because they look like giant rats but they are not in the Rodentia family that includes the rat, mouse, squirrel and other familiar rodents. Marsupials are considered to be the closest living relative of placenta mammals.
When wehear the word marsupials we generally think of animals living in Australia which is located a few thousand miles from North America. So, how did an animal with a pouch ended up halfway around the world separated from the rest of the marsupials and now lives in North America. The answer may surprise you.Read on.
Opossum Facts: A Little Natural History
The habitat of opossums is pretty wide spread. It covers most of North America up into portion of Ontario and extends as far south through Central America to the top of South America. Opossums are generally found near swamps and on the banks of streams. They are solitary, arboreal animals so they spend a lot of their time in trees.
There are two species of opossums, the first and largest group is called the Virginia Opossum or North American Opossum and the second group is called the Southern Opossum. The Southern Opossum is sometimes called the Common Opossum. The Virginia Opossum ranges in length from 13 inches up to 37 inches and male opossum can weigh as much as 14 pounds. The female tops out at about 8 pounds. Generally, the larger opossums are found mostly in the cooler northern regions and the smaller ones are found near the tropic. Their fur is usually grayish in color.
The Southern Opossum has a habitat range from southern Mexico down to Bolivia in South America. They are pretty much the size of a domestic cat. These opossum spend most of their time on the ground instead of the tree as the Virginia Opossum does. The Southern Opossum’s fur is grayish with some reddish coloring blended in it.
Opossums have a few unusual features. They have a long hairless, pensile tail about 9 to 19 inches long. They are the only animals other than primates with an opposable thumb. The odd thing is located on their rear limbs, which give them the ability to hang upside down from tree limbs if they are not using their tail to hold on to the limb. The opossum has 5 to 9 babies one to three times a years and female raises them without any help from the father. The life span of an opossum is about 2 years in the wild and they can live up to four years in captivity.
The Opossum Unusual Defense Against Predators
Everyone is familiar with the phrase, “playing possum”. This is when an opossum plays dead or pretending to be injured to discourage predators from attacking them. When an opossum is in this state he is actually in a coma and can remain this way for up to four hours. It looks pretty convincing when you see one doing this fake death routine. His tongue is hanging out of its opened mouth lying on his side and his eyes are open. He also emits a putrid odor from his body with green fluid emanating from his anus. Animals will leave him alone and even us when we see him in that state. But on the other hand they can become ferocious when they are threaten sometimes.
How Did The Opossum Become A North America Marsupial
An opossum like mammal first appeared on the North America continent more than 65 million years ago after the extinction of the dinosaurs. Researchers have determined, based on fossil evidence, that around this time there were two groups of pouch bearing animals living in North America. These two large groups of marsupials migrated from North America down through Central America to South America. The migration came to an end when North America and South America separated during the Cretaceous Period. While in South America some of these animals migrated to the other continents when Antarctica and a course Australia were all joined with South America. Fossils found on these continents indicated these large bodies of land were once joined to South America about 65 million years ago.
Then about 20 million years ago all the North American marsupials went extinct and North America was later repopulated with two marsupials when the Isthmus of Panama formed about 3 million years ago to reconnect the two continents thus restarting the migration process. The two marsupials that migrated north from South America were the Virginia Opossum, presently found in the southeastern region of North American and the Southern Opossum found mostly in the region of Mexico. Some opossums are presently found in the western portion of the United States. They were introduced there during the Great Depression in 1929 as a source of food and have since been seen as far north as northwestern Canada. I am sure many of you have heard of opossum stew. I heard it is very good. Today these are the only marsupials living in North America and it is the only other place in the world besides Australia where marsupials live. These opossums are living were the marsupials originally lived before moving to Australia.
Marsupials such as kangaroos, Tasmanian devil, marsupial mouse and other animals of this class were not always living in Australia, as many people believe today. They originated from North America and eventually migrated there. Today the opossums are living where they all started in North America.
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