The North American Opossum (Didelphis virginiana) is known as a timid, non-aggressive marsupial that prefers avoidance. When threatened, it is famous for its passive, involuntary defense mechanism. Despite this tendency, opossums are wild animals that must compete for survival. While fighting is not their preferred interaction, opossums do battle each other under specific circumstances.
Possum Social Structure and Baseline Aggression
Opossums are solitary animals, spending most of their short lifespans alone. Their only social grouping occurs during mating season or when a mother is raising her young. This solitary nature significantly reduces opportunities for intraspecies conflict. They do not maintain fixed territories; their home ranges often overlap, and they wander without establishing rigid boundaries.
The opossum’s low-energy lifestyle contributes to its non-aggressive disposition. They have a low metabolic rate and are primarily nocturnal, favoring slow, deliberate movement and avoidance over high-energy conflict. This preference for retreat conserves energy and minimizes the risk of injury, which could be fatal for a solitary animal.
When and Why Possums Fight
Physical fighting between opossums is rare, occurring only when resources are concentrated or during the breeding cycle. The most common trigger is competition over a limited, high-value food source, such as a dumpster or a pet food bowl. When two animals converge, the instinct to secure the meal overrides their tendency to disperse. These conflicts are usually focused and short-lived, aiming to displace the competitor from the food.
Intense aggression arises among males during the breeding season, which spans from winter through late summer. Males engage in rivalry to establish mating access to females. These reproductive battles involve biting, often targeting the opponent’s neck and throat area. Such fights involve noise and posturing but generally cease once one male retreats, rarely resulting in death. Females can also be aggressive toward other opossums, particularly when defending a den site where they are raising their litter.
Threat Displays and Conflict Resolution
When a fight is imminent or a threat is perceived, opossums employ a series of aggressive displays designed to intimidate and deter the opponent without escalating to full physical contact. They arch their backs and stand their fur on end to appear larger than they are. A key part of the display involves baring their fifty sharp teeth, the most of any North American land mammal, which is accompanied by a dramatic hissing or screeching sound.
If these initial threat displays fail to resolve the conflict, the opossum may resort to its most famous, and involuntary, defense mechanism: tonic immobility. This state, commonly called “playing possum,” is a physiological response triggered by extreme stress. The animal collapses, its body goes limp, and its heart rate and breathing slow drastically, giving the appearance of death.
To complete the illusion, the opossum’s jaw may slacken and drool, and it secretes a foul-smelling substance from its anal glands, mimicking the odor of a decaying carcass. This behavior is highly effective because many predators prefer live prey and lose interest in a seemingly dead, noxious meal. The feigning of death is the animal’s final attempt to de-escalate a confrontation and survive.