The North American opossum is the only marsupial found north of Mexico, often encountered by domestic cats in suburban and urban environments. These nocturnal animals are often misunderstood, leading to concerns about their behavior toward household pets. While they possess fifty sharp teeth, giving them a fearsome appearance, opossums are generally non-aggressive and prefer to avoid confrontation. The typical interaction between a cat and an opossum is one of avoidance or shared scavenging, not territorial conflict.
The Truth About Possum Aggression
Opossums are solitary, nomadic creatures whose primary goal is survival through stealth and avoidance, not combat. Unlike many other backyard mammals, they do not establish territories to defend, which significantly reduces the motivation for aggression. These marsupials are omnivorous scavengers, meaning they are far more interested in an easy meal, such as fallen fruit or spilled pet food, than in engaging a potential predator. Fights between an opossum and a cat are extremely rare, usually only occurring if the opossum is cornered or if a mother is protecting her young.
The opossum’s naturally slow speed and lack of strong fighting ability mean confrontation is a last resort. Opossums can inflict a painful bite if they are captured or feel their life is truly threatened, but this is a defensive action, not a predatory one. In most cases, a cat will approach a foraging opossum, the opossum will react defensively, and the cat will quickly retreat, often startled by the display. When faced with a perceived threat, the opossum’s natural instinct is not to attack but to deploy a variety of startling defensive displays.
Possum Defensive Behaviors
When an opossum feels threatened by a cat or another predator, it relies on a specific toolkit of non-aggressive, involuntary stress responses. The most well-known of these is tonic immobility, colloquially known as “playing possum.” This reaction is an involuntary physiological state that mimics death, often triggered by extreme fear. The animal collapses onto its side, the body becomes rigid, breathing slows, and the mouth hangs open with the tongue exposed.
Accompanying this feigned death, the opossum may also drool excessively and secrete a foul-smelling fluid from its anal glands. This combination of an inert body and a putrid odor is intended to convince a predator that the opossum is diseased or already dead, making it an unappetizing meal. Before resorting to this extreme measure, the opossum will first try to deter the threat by opening its mouth wide to reveal its fifty teeth, hissing, and growling. These behaviors are intended to scare the aggressor away, acting as a bluff rather than preparation for a sustained fight.
Health Risks Associated with Possums
While opossums are not typically aggressive, the primary concern for pet owners is the potential for disease transmission. Opossums are highly resistant to the rabies virus due to their low internal body temperature. However, they are carriers of numerous other pathogens and parasites that can affect domestic animals.
Opossums can transmit bacterial infections such as leptospirosis through their urine, which can contaminate soil and water sources. They also carry parasites like coccidia, which are shed in their feces and can cause intestinal disease in pets. The greatest indirect risk comes from external parasites; opossums are hosts for fleas, ticks, and mites. These parasites can easily transfer to a cat, potentially exposing the pet to diseases like flea-borne typhus or Lyme disease.
Strategies for Preventing Encounters
The most effective approach to preventing encounters between cats and opossums involves removing the primary factors that attract the marsupials to a property: food and shelter. Opossums are nocturnal, so bringing all pet food and water bowls indoors before dusk eliminates a major attraction. Securing garbage cans with tight-fitting or locking lids will prevent opossums from scavenging discarded food.
Cat owners should also ensure that pet doors are sealed or secured at night to prevent opossums from wandering into the home. Minimizing potential outdoor den sites, such as clearing brush piles, sealing off access points beneath porches, and securing sheds, will discourage opossums from taking up residence near the house. These preventative measures focus on making the yard less appealing to the opossum, which naturally reduces the chance of interaction with a cat.