Opossums on the Move

By: Cholla Nicoll, Borderlands Wildlife Preserve Lead Technician

​A recent review paper in the journal Global Change Biology titled “Tropicalization of temperate ecosystems in North America: The northward range expansion of tropical organisms in response to warming winter temperatures” explains how tropical organisms are beginning to move northward in response to global climate change. One of the species on the move in our region is the Opossum.

​The name "opossum" originates from the Algonquian word "apasum," meaning white animal. There are over 100 different opossum species found in the Americas. Yet, the Virginia Opossum and the common opossum are the only two species of opossum and only marsupials naturally occurring in the United States and Canada. (Just in case you are wondering, the correct term is "Opossum", "Possum" is the term used for a different marsupial family found in Australia.) As climate change increases average winter temperatures, the range for the opossum and other tropical species is also expanding into these recently warmer and less snow-covered areas.

​The opossum has many superpowers. This fantastic creature enters the world about the same size as a honeybee and lives out its life span in the matter of one to two years. Opossums are gentle creatures. Although they have 50 sharp teeth when a bite does not deter a predator, their primary defense when threatened is to drool, appear unappetizing, and play dead. Playing dead is thought to be an involuntary response and, unfortunately, does not work on domestic dogs. Outside of this well-known unique behavior, opossums also build nests using their tail as a fifth appendage to gather materials. Opossums also seldom contract rabies due to a naturally low body temperature and are resistant to venomous snake bites. To top off their superpowers, opossums consume many pests, including snails, slugs, mice, and 95% of ticks that they meet by some estimates.

As we accept the reality of a changing climate, I would like to suggest keeping the famous quote from Fred Rodger's mother in mind “Look for the helpers. You will always find people who are helping.” Remember, people are not the only helpers. We also have many animals like the opossum who are on the move and ready to help.

​Valuing helping animals like the opossum, which can help with pest mitigation, will be essential to our survival and maintaining a balanced ecosystem. If you encounter an opossum, the best thing to do is to leave them alone. They are rarely in any one area for more than a few days. Help opossums avoid humans and dogs by keeping a tidy outdoor space free of pet food, clutter, and trash. If you find an injured opossum contact your local animal control or wildlife rehabilitation center. 

 Our local wildlife rehabilitation center is the Tucson Wildlife Center.

For more information on how to live with opossums, please visit the Opossum Society of the United States.

Opossum trail camera video and pictures courtesy of the TNC Patagonia Sonoita Creek Preserve.

BWP wildlife monitoring during 2021- 2022 supported by the Wildlife Conservation Society Climate Adaptation Fund established by the Doris Duke Charitable Foundation to fund critical ecological restoration work along the path of the jaguar in southeast Arizona.

​Read more about this project.