Raccoons and Virginia opossums are highly adaptable mammals that thrive in urban and suburban environments across North America. Their nocturnal foraging habits and tendency to seek shelter in human structures often lead to conflict. This exploration examines the various factors contributing to the mortality of these animals, encompassing natural hazards and the significant risks associated with human intervention, particularly lethal control methods. Understanding the causes of death highlights the importance of responsible, non-lethal management strategies.
Natural and Environmental Causes of Death
In natural settings, the lifespan of a raccoon or opossum is considerably short, often ranging from two to four years due to constant environmental pressures. Predation is a persistent threat, particularly to younger individuals, with coyotes and large raptors, such as great horned owls, actively hunting both species. Domestic dogs also represent a significant predator risk in residential areas, often engaging in fatal encounters. Disease represents another major cause of natural mortality, particularly for raccoons, which are susceptible to highly contagious viral infections like Canine Distemper Virus (CDV). Raccoons are also the primary terrestrial carrier of rabies in many eastern states, a neurological disease that is almost invariably fatal once symptoms appear.
Opossums, conversely, possess a robust immune system and a naturally lower body temperature, which makes them less susceptible to the rabies virus. However, they are not immune to other pathogens and parasites, and young opossums frequently succumb to starvation or exposure during their first year. For both species, vehicle collisions in suburban and urban areas are statistically one of the most frequent causes of death, especially as they cross roads at night while foraging. The opossum, in particular, is often cited as one of the most common roadkill victims in regions where it is prevalent.
Human-Induced Lethal Control Methods and Dangers
Intentional lethal control methods employed by humans pose indiscriminate risks. Chemical agents, most commonly rodenticides, are a major source of wildlife mortality. These compounds are typically anticoagulant poisons that interfere with the animal’s ability to recycle Vitamin K, necessary for blood clotting. The result is a slow death from internal hemorrhage. Second-generation anticoagulant rodenticides (SGARs), such as brodifacoum, are especially hazardous because they are highly potent and persist in the animal’s tissues.
Raccoons and opossums can suffer primary poisoning by consuming the bait directly. More frequently, these scavengers are victims of secondary poisoning, consuming rodents that have been weakened or killed by the poison. This bioaccumulation of toxins creates a significant hazard for non-target wildlife, including raptors, domestic pets, and other scavenging mammals. Lethal trapping methods, such as body-gripping traps or snares, are designed to kill instantly but present a risk of capturing and severely injuring non-target animals. The use of any poison not specifically registered for the target species is generally prohibited due to these wide-ranging, indiscriminate dangers.
Legal Restrictions on Lethal Wildlife Removal
Wildlife control is governed by complex state and local regulations that restrict lethal removal by the general public. Most jurisdictions require a permit, often a Nuisance Wildlife Control Operator (NWCO) license, for individuals or companies to lethally remove problem animals for a fee. Attempting to use poisons to kill a raccoon or opossum is illegal in many states, reflecting the high risk of secondary poisoning and potential harm to children or pets.
Live trapping, while seemingly humane, is also heavily regulated due to concerns over disease transmission, especially rabies. Many states prohibit the relocation of trapped wildlife, requiring instead that the animal either be released immediately on-site or humanely euthanized. The rationale for this restriction is that translocating a wild animal can spread diseases to new populations and drastically reduce the survival chances of the released animal, as it lacks familiarity with the new territory. Citizens attempting to manage nuisance wildlife without a clear understanding of these laws risk substantial fines or criminal penalties.
Non-Lethal Exclusion and Deterrence Strategies
The most effective approach to managing conflicts involves non-lethal exclusion and habitat modification. Exclusion focuses on physically blocking access to secure areas, such as using half-inch galvanized hardware cloth to cover vents, chimneys, and foundation openings. Since both species are adept at climbing and digging, a professional installation of chimney caps and L-shaped wire mesh barriers along the base of decks or sheds is necessary.
Habitat modification centers on removing the attractants that draw these resourceful animals to a property. Securing food sources is paramount, which involves using wildlife-proof trash can lids secured with bungee cords or locks, or storing garbage containers inside a secure garage or shed. Pet food should never be left outside overnight, and fallen fruit or spilled birdseed must be routinely cleaned up.
Deterrents can offer short-term relief but are generally less effective than exclusion for long-term control. Motion-activated devices that combine loud sounds with sudden, bright strobe lights can startle nocturnal visitors. The effectiveness of these devices is often temporary, however, as raccoons and opossums are intelligent and quickly habituate to consistent stimuli. Combining these deterrents with strong-smelling substances like ammonia-soaked rags near entry points can create an unpleasant environment.