O Possum

In 2009, one study published results that indicated opossums are mass destroyers of ticks. The public loved the idea, and the meme went viral. Since then, subsequent studies have disputed the 2009 results, undermining the opossum's newfound popularity.

The Virginia opossum, also known as the common opossum, has always had public image issues. They are somewhat homely with pointed faces housing 50 teeth in their mouths (the most of any mammal) and a prehensile hairless tail with which they can grab branches or carry small objects. Young possums hiss or growl like cats when threatened. If adult possums feel very threatened, they will feign death, or "play possum", waiting until the threat is gone before moving again.

Omnivorous, they eat almost anything; insects (including but not exclusively ticks), lizards, frogs, fish, crayfish, snakes, small birds, rodents and young rabbits in addition to seasonal plant foods. Like most omnivores, they also scavenge from human provided food sources like bird feeders, vegetable gardens, compost piles, garbage cans and pet food dishes. Graced with immunity to pit viper venom, they regularly prey on these snakes. So even if they don't eat ticks by the thousands, they do eat venomous snakes and other garden pests.

They are the only American marsupial that lives north of Mexico. American marsupials are not related to Australian marsupials although they do reproduce in the same manner. Technically mammals, they birth their young very immature and the newborn crawls into the mother's pouch and latches onto a teat to finish its development.

Unlike other mammals, opossums appear to be resistant to rabies. This is believed to be due to their lower body temperature. Despite the advantages of snake venom and rabies resistance, opossum life spans are very short, about 2 years in the wild. Their need for high levels of calcium in their diet leads them to gnaw on carrion bones, often near the side of a road, making them easy targets for cars. They are also at the mercy of larger predators.

Opossums are considered shy and harmless unless cornered and forced to defend themselves. They prefer to climb away from danger, using their prehensile tails like a fifth limb. They are not generally aggressive and only bite when escape is not an option. Historically they have been hunted for their meat and fur. Opossums evolved in the tropics and are very sensitive to extreme cold. They do not build up large fat reserves like bears and raccoons. If the winter temperatures drop below 20°F (-6°C), possums will find warm dens and try to sleep through the coldest weather. They are also susceptible to frostbite on their hairless ears, toes and tail. Possums change dens frequently to avoid predators.

Opossums do, however, carry a parasite known to cause Equine Protozoal Myeloencephalitis that is spread through their droppings. This disease causes neurologic signs in horses and can be life threatening. Horse owners can minimize this risk by making their property less appealing to possums. Secure garbage cans and compost containers or store them in a secure shed or outbuilding. Thoroughly clean all outdoor eating areas, especially around the barbeque. Do not feed opossums or leave pet food outside. Bring dogs and cats indoors at night. Thoroughly examine all structures for access to possible denning sites. Deny this access by covering entry holes with sturdy materials like hardware cloth, boards or metal flashing.

Like many other wild animals, opossums have become comfortable enough around humans to take advantage of our messiness. Despite their willingness to benefit from our generosity, these animals are not domesticated! Keeping wild animals as pets is illegal in many areas. Keep the dogs and cats inside; leave the wild animals outside.