Spiders are arachnids whose life cycles include the egg, the spiderling, and the adult. Determining when a spider dies is complex, as there is no single duration that applies to all species. Lifespan is highly variable, ranging from a few months to several decades, depending on genetics, sex, and environmental conditions.
Lifespan Variability Across Species
The most significant factor influencing a spider’s lifespan is its species, which determines its potential for longevity. Spiders are broadly separated into two categories based on their lifespan: the annual and the perennial.
Annual spiders, such as common house spiders, orb-weavers, and many jumping spiders, typically live for only one to two years. They often reach maturity, reproduce, and die before winter, completing their entire life cycle within a year or two.
Perennial spiders, including larger, burrowing species like tarantulas and trapdoor spiders, possess an impressive potential for long life. Female tarantulas commonly live for 15 to 25 years in ideal conditions. The oldest recorded spider, a female trapdoor spider in Australia, lived for an astonishing 43 years in the wild.
The physiological difference between these groups is tied to their growth and reproductive strategies. Mygalomorphs, which include tarantulas and trapdoor spiders, continue to molt even after reaching adulthood, allowing them to grow and potentially regenerate lost limbs. Shorter-lived spiders generally stop molting once they become sexually mature adults. This long-term growth and slower metabolism contribute directly to the extended life expectancy of the larger species.
Gender and the Timing of Death
Gender plays a dramatic role in determining how long a spider lives, particularly in species with longer lifespans. Male spiders universally have significantly shorter adult lives than their female counterparts. Once a male reaches sexual maturity, its primary purpose is reproduction, and its subsequent life expectancy is sharply reduced.
The male’s death often follows shortly after mating, resulting from exhaustion, physiological decline, or sometimes predation by the female. Male tarantulas, for instance, may only survive one to six years after maturity, contrasting sharply with the female’s decades-long potential. This reproductive strategy ensures the female survives to complete the reproductive cycle.
The female’s extended lifespan is necessary to ensure the survival of the next generation. She must endure long periods of gestation and often guards the egg sac until the spiderlings hatch. In some species, the female continues to protect or even feed the young spiderlings after they emerge. This parental investment requires a robust physiology that allows the female to outlive the male by a considerable margin.
External Factors That End a Spider’s Life
Beyond natural aging, a spider’s life is often cut short by a variety of environmental and physical threats.
One of the most common causes of mortality in growing spiders is a failed molt, a process known as dysecdysis. Spiders must shed their rigid exoskeleton to grow, and if they become stuck in the old skin, they can suffer fatal injury or suffocation.
Dehydration is a significant risk, as it can prevent the spider from successfully extracting itself during molting. The new exoskeleton is extremely soft and fragile, making the spider vulnerable to fatal abdominal ruptures if it falls or is mishandled. A damaged abdomen can lead to a lethal leakage of hemolymph, the spider’s blood.
Predation is another major cause of early death. Insects like the tarantula hawk wasp specifically target spiders, paralyzing them and laying an egg to provide a live host for their larva. Environmental extremes, such as freezing temperatures or excessive dryness, quickly compromise a spider’s survival. Starvation is also an ever-present threat, particularly if prey becomes scarce.