Virginia opossums: The American marsupials that have barely changed since the time of the dinosaurs
Rapid facts
Name: Virginia Opossum (Didelphis Virginiana))
Where he lives: Central and North America
What he eats: Fruits, insects, small animals and carrion
With their bright eyes, their big ears, their hairless tails and their short and trapual legs, the opossums are distinctive marsupials. Despite their strange appearance, these animals have a rich evolutionary history and have been largely unchanged for millions of years. Their remarkable ability to adapt to different environments, food sources and predators helped them to survive from the time of dinosaurs to today.
Virginia opossum is the only species of opossum found in the United States and Canada. Opossums have the smallest brain / weight ratio of any North American mammal.
The first known parents of modern opossums lived over 65 million years ago, when dinosaurs have turned off. A 2009 study Published in PLOS One revealed that the Péradectides, a family of known marsupiaux of fossils mainly in North America and Eurasia, are the most extinct parents of living opossums. Like modern opossums, the Peradectides had opposable thumbs on their posterior feet and a skull of similar shape – characteristics that have remained almost unchanged for millions of years. The first opossum fossils date back to the Miocene era, about 20 million years ago.
One of the main reasons why opossums have survived for so long with few changes is that they are adaptable. These marsupials eat almost anything, including fruits, insects, small animals and animal carcasses. They can live forests at urban backgrounds. And, although they are mainly nocturnal, they can sometimes be seen in daylight if the food is rare.
Opossums are also resistant to snake venomIn particular that of bell snakes and other pit vipers. This resistance is due to a protein called a neutralization factor of lethal toxin found in their blood, which can neutralize various toxins in snake venom. This allows opossums to tackle poisonous snakes which would otherwise be a threat.
Opossums give birth to underdeveloped young people, who crawl in a pocket and a nurse for about eight weeks as they grow. The young opossums then get on their mother’s back for several weeks until they become independent at 12 weeks.
When threatened, opossums can grow, whistle, strip of teeth or climb a tree nearby to escape. If an escape is not possible, they use “playing to death” – a defense mechanism known as the name tonatosis.
This reaction is not a conscious decision but a physiological response to extreme stress. This means that the opossum becomes completely motionless and seems lifeless. This behavior is often accompanied by a significant drop in heart and respiratory frequencyA decrease in body temperature and the release of a nauseating liquid of the anal glands. Together, these signals signal to predators that the opossum is already dead, often making them lose its interest and move on. If involuntarily, “playing opossum” allows animals to survive the meeting.
