Rabbits, particularly the Eastern Cottontail, are common residents of suburban and residential landscapes across the United States. Despite their rapid reproductive rate, wild rabbit populations experience extremely high annual mortality, sometimes reaching 80% in a given year. The average lifespan for a cottontail is often less than one year. While rabbits are naturally a prey species, the specific causes of death in a human-dominated yard setting are often linked to a combination of natural predators, virulent diseases, and various hazards introduced by human activity.
Common Predators in Residential Settings
The greatest source of predatory loss for rabbits in a residential setting comes from common domestic animals. Unsupervised dogs and outdoor cats are highly effective hunters that view rabbits as easily accessible prey. The innate predatory instinct of a house cat often leads to the stalking and capture of rabbits, especially vulnerable young kits.
Injuries inflicted by cats often prove fatal, even when wounds appear minor, due to the introduction of bacteria. A cat’s claw or bite can inject harmful bacteria, such as Pasteurella multocida, deep into the tissue, leading to a swift septic infection. Studies examining wildlife presented to clinics frequently show that cat-related trauma is a leading cause of death for rabbits. Furthermore, dogs with strong chasing instincts can easily run down and kill an adult rabbit in a yard environment.
Beyond domestic pets, opportunistic urban wildlife also hunts rabbits within suburban boundaries. Coyotes and foxes have adapted successfully to residential areas and utilize yard cover and green spaces for hunting. Birds of prey, such as hawks and owls, also pose a significant threat from above, watching open lawns for foraging rabbits. These wild predators are often drawn to areas with dense shrubbery or brush piles, which rabbits use for shelter, turning these hiding spots into potential ambush sites.
Fatal Viral and Bacterial Diseases
Diseases represent an invisible but often more widespread cause of mass mortality than predation. Rabbit Hemorrhagic Disease Virus Serotype 2 (RHDV2) is a highly contagious calicivirus that has spread across North America, affecting both wild and domestic lagomorphs. This virus attacks the rabbit’s internal organs, causing liver damage and widespread hemorrhaging.
RHDV2 is characterized by an extremely high fatality rate, often approaching 100%. It can be transmitted through direct contact, feces, urine, and contaminated objects like shoes or clothing. The virus often acts so rapidly that the only sign of infection is sudden death, sometimes with bleeding from the nose or other orifices. Its speed and environmental persistence pose a threat to entire localized rabbit populations.
Myxomatosis is another severe viral disease, primarily transmitted by biting insects such as fleas and mosquitoes. This poxvirus causes characteristic swelling around the eyes, face, and genitals, giving the rabbit a “big head” appearance. Wild rabbits that contract myxomatosis have a low survival rate, often succumbing to the disease within two weeks. Death frequently occurs from secondary bacterial infections like pneumonia, as the virus compromises the rabbit’s immune system.
Tularemia, sometimes referred to as “rabbit fever,” is a bacterial disease caused by Francisella tularensis that represents a public health concern. Infected rabbits may exhibit signs of lethargy, weakness, or uncoordinated movement, though many are simply found dead. The bacteria is commonly transmitted by ticks and deer flies. It can also be passed to humans and pets through direct contact with an infected animal’s tissue or blood.
Accidental and Man-Made Hazards
Human activity and residential infrastructure introduce numerous hazards that cause accidental death and toxicoses in rabbits. One significant danger is the ingestion of toxins, particularly rodenticides, which are often placed to control mice and rats. Rabbits can suffer direct poisoning by consuming the bait, or secondary poisoning by eating a rodent that has ingested the poison.
Anticoagulant rodenticides interfere with the blood’s clotting ability, leading to fatal internal bleeding. Other garden chemicals, including pesticides, herbicides, and slug pellets, also pose a direct poisoning risk to foraging rabbits. Additionally, many common ornamental plants are toxic, such as daffodil and tulip bulbs, foxglove, and deadly nightshade, which rabbits may consume while grazing.
Vehicle traffic, even in suburban neighborhoods, is a frequent cause of fatal trauma for wild rabbits. Rabbits are often struck by cars on roads or in driveways while crossing or foraging near the pavement edge.
Yard maintenance equipment is another source of lethal injury, especially to young rabbits. Mother rabbits build shallow nests, called “forms,” often hidden in the middle of tall grass on a lawn. Mowers and string trimmers can unintentionally cause severe injuries to these vulnerable, immobile kits.
Finally, physical obstacles created by homeowners can lead to fatal injuries or drowning. These hazards include poorly secured fencing, uncovered window wells, or swimming pools.