Snakes, like all living organisms, face mortality. Their lives, whether in the wild or human care, are subject to various factors that can lead to their demise. Understanding these causes provides insight into the challenges these reptiles encounter.
Environmental and Predatory Dangers
In natural habitats, snakes face various threats. Predation is a significant factor, with many animals hunting them. Birds of prey like hawks and eagles snatch snakes from above, while carnivorous mammals such as mongooses, bobcats, and wolverines capture them on the ground. Larger snake species also prey on smaller ones.
Environmental conditions also play a substantial role. Extreme weather events, including prolonged droughts, can lead to severe dehydration and starvation. Intense floods or wildfires force snakes from shelters, exposing them to new dangers and displacing them from food sources.
Temperature extremes also impact these ectothermic animals, which rely on external heat to regulate body temperature. Both extreme cold (hypothermia) and intense heat (hyperthermia) can be fatal if snakes cannot find suitable microclimates. Resource scarcity, such as a lack of prey, can cause starvation, though many snake species can endure long periods without food by significantly reducing their metabolic rates.
Human-Related Mortality
Human activities significantly contribute to snake mortality, often indirectly through environmental alterations. Habitat destruction, driven by urbanization, agriculture, and deforestation, fragments natural landscapes and eliminates crucial snake habitats. This forces snakes into smaller, isolated areas, increasing their vulnerability and reducing access to food and shelter.
Road mortality is another prevalent human-induced cause of death. Snakes frequently cross roads for thermoregulation or to access resources, making them susceptible to being struck by vehicles. Many road encounters result in fatalities, sometimes due to intentional targeting by drivers.
Many snakes are also killed directly by humans out of fear or misunderstanding. This intentional killing, often stemming from a perceived threat or pest control efforts, reduces snake populations, regardless of whether the species is venomous. Pollution also poses a threat; pesticides, herbicides, and other chemical contaminants can poison snakes directly or indirectly through contaminated prey. Finally, the illegal wildlife trade, including poaching and unsustainable collection for the pet market, places immense pressure on wild snake populations, particularly for species with slow reproductive rates.
Internal Health Decline
Snakes, like all organisms, face internal biological challenges that can lead to their demise. While often obscured by external threats in the wild, old age eventually causes natural deterioration and organ failure. In controlled environments, where external dangers are minimized, snakes can reach their full lifespan, exhibiting signs of aging such as reduced activity.
Diseases also play a role in snake mortality. These include bacterial infections, such as mouth rot (stomatitis), respiratory infections, and skin conditions like ulcerative dermatitis, which can lead to septicemia if untreated. Viral diseases, including Inclusion Body Disease (IBD) and Ferlavirus, can cause severe systemic illness, often affecting the nervous or respiratory systems.
Fungal infections also contribute to health decline. Heavy parasitic infestations, both internal (e.g., lungworms, nematodes) and external (e.g., mites), can significantly weaken a snake, leading to organ damage, compromised immune function, and death. Some genetic abnormalities or birth defects can also result in non-viable offspring or early mortality.
Challenges in Captivity
Snakes in human care face specific risks from their artificial environments. Inappropriate husbandry practices are a primary cause of health problems and mortality in captive snakes. Incorrect temperature gradients, insufficient humidity, or improper lighting can lead to stress, metabolic issues, respiratory infections, and shedding difficulties.
Chronic stress, often resulting from an unsuitable enclosure size, lack of adequate hiding places, or excessive handling, can suppress a snake’s immune system, making it more susceptible to illness. Accidental injuries are also common, occurring from unsuitable enclosure furniture, improper handling, or live prey. Rodents, if left unattended with a snake, can bite and inflict severe wounds that may lead to infection or death. Escaped captive snakes often face a grim fate. If they leave their enclosures, they are exposed to unsuitable environmental conditions, lack of familiar food sources, or predation, significantly reducing their chances of survival.