Squirrels are a familiar sight in many natural and urban landscapes. While predation by other animals is a natural cause of death, squirrels frequently perish from circumstances where they are not consumed. Understanding these non-predatory fatalities offers insight into the challenges these rodents face.
Accidental and Environmental Dangers
Squirrels frequently encounter dangers that result in accidental death. Vehicle collisions, particularly in urban and suburban areas, represent a significant cause of mortality, as squirrels often cross roads to access food sources or navigate their territories. Electrocution is another common fatal accident, occurring when squirrels climb utility poles or traverse power lines, leading to death.
Drowning can also be a lethal accident for squirrels, especially in uncovered swimming pools, rain barrels, or other water containers where they cannot escape. Falls from trees or other high structures, while less common for agile squirrels, can result in fatal injuries, especially for younger or infirm individuals. Environmental factors further contribute to non-predatory deaths, including extreme weather events such as severe blizzards or prolonged heatwaves. These conditions can lead to hypothermia or hyperthermia when shelter or water sources are scarce.
Natural disasters like floods or wildfires can devastate squirrel populations by destroying their habitats. When their food sources are diminished due to habitat loss or prolonged periods of scarcity, squirrels can also succumb to starvation. This is more pronounced during harsh winters.
Disease and Parasitic Threats
Diseases represent a silent but significant threat to squirrel populations, often leading to death without any external consumption. Squirrel pox, a viral infection, can cause skin lesions that may become severe, impairing vision or feeding, ultimately leading to starvation or increased vulnerability. Bacterial infections, such as Salmonella from contaminated food or water, can lead to severe gastrointestinal distress and systemic illness. Pneumonia, another bacterial infection, can particularly affect squirrels during periods of stress or cold weather.
Fungal infections can also impact squirrels, though generally less common unless the animal is immunocompromised. Heavy parasitic loads, rather than individual parasites, can severely weaken a squirrel. Extensive infestations of fleas, ticks, or mites can lead to significant blood loss, causing anemia and making them more susceptible to disease. Internal parasites, such as worms, can cause organ damage or nutrient malabsorption, leading to emaciation and death.
Non-Consumptive Animal Interactions
Other animals can cause the death of a squirrel without consuming it, often due to territoriality or failed predatory attempts. Squirrels engage in disputes with other squirrels, particularly over mating rights or foraging territories, which can occasionally escalate into fatal fights. Larger rodents or even aggressive birds might also injure or kill a squirrel during competitive interactions.
Domestic cats and dogs, despite being predators, frequently kill squirrels during hunts or “play” but then abandon the carcass without eating it, driven by instinct rather than hunger. Wild predators, such as some birds of prey or foxes, may also injure or kill a squirrel during a hunt that is subsequently interrupted or abandoned, leaving the squirrel intact. Indirect animal interactions, such as larger animals disturbing a squirrel’s nest, can lead to infant mortality from exposure or injury.
Human-Influenced Dangers
Human activities and their byproducts contribute significantly to non-consumptive squirrel deaths. Accidental ingestion of rodenticides, known as rat poison, is a frequent cause of fatality for squirrels. These poisons are designed to be palatable to rodents but cause internal bleeding and death over several days, often without consumption by another animal. Other environmental toxins or pesticides can also inadvertently harm squirrels if ingested.
Squirrels can also die in traps not specifically intended for them, such as those for other nuisance animals. Even humane traps, if left unchecked, can lead to stress, exposure to elements, or injury that proves fatal. Habitat alteration, including rapid urbanization and deforestation, can indirectly lead to squirrel deaths. The destruction or fragmentation of natural spaces reduces available food sources and shelter, increasing vulnerability to starvation, exposure, or road accidents.