Spiders exhibit a life expectancy that ranges dramatically, from creatures that complete their entire lifecycle in a few months to individuals that can survive for decades. This variability is a direct result of their evolutionary history, separating them into two major infraorders with fundamentally different approaches to aging. While the vast majority of species follow a quick life cycle, a small, specialized group can display longevity that rivals some vertebrates.
The Range of Spider Lifespans
Spider lifespans are broadly categorized by their infraorder, with two distinct groups showing dramatically different survival strategies. The first group, Araneomorphs, includes common house spiders, orb weavers, and jumping spiders, accounting for the overwhelming majority of species. These spiders are short-lived, with most individuals in temperate climates surviving for only one to two years, often dying after their single reproductive season. This short lifespan aligns with a high-activity, rapid-development strategy.
The second group, Mygalomorphs, includes tarantulas, funnel-web spiders, and trapdoor spiders, and they are renowned for their slow growth and long lives. Female mygalomorphs frequently live for 10 to 25 years, a stark contrast to their shorter-lived cousins. These spiders often take several years to reach sexual maturity, indicating a low-risk, long-term survival strategy.
Factors Determining Longevity
A significant predictor of longevity is the creature’s metabolic rate, which is directly linked to size. Larger spiders tend to have slower metabolisms and consequently live longer. Mygalomorphs, often the larger spiders, benefit from this slower pace of life, which reduces the biological wear and tear associated with constant activity.
Environmental stability is also a major determinant of survival, particularly for species that do not live in protective burrows. Spiders that inhabit stable environments, such as mild climates or the interior of human dwellings, live longer than those exposed to harsh weather fluctuations or frequent food scarcity. Female spiders across most species significantly outlive males, who often reach maturity quickly and die shortly after mating, sometimes within weeks or months.
The Longest-Lived Species
Burrowing trapdoor and tarantula species possess specific biological adaptations that enable their extended lifespans. Their sedentary nature means they expend minimal energy, reducing their exposure to predators and environmental stress. These spiders possess specific biological adaptations that enable their extended lifespans.
The record for the longest-lived spider belongs to a female trapdoor spider, Gaius villosus, known to researchers as “Number 16.” This individual was monitored in the wild in Australia for 43 years, from 1974 until her death in 2016. Her longevity is attributed to her low metabolism and the protection of her deep, silk-lined burrow, which provides a consistently stable microclimate. The slow, deliberate life cycle of these spiders, including infrequent molting even after reaching maturity, contributes to their exceptional age.
Monitoring Spider Age
Determining the age of a spider, particularly one that lives for decades, requires dedicated, long-term scientific observation. Scientists typically rely on marking or tagging individuals and their habitats in the wild as part of multi-decade population studies. In the case of the record-holding trapdoor spider, researchers marked the entrance to her burrow and returned annually to check on her status.
For long-lived species that continue to grow after reaching maturity, size and the frequency of molts can offer an estimate of age, though molting slows considerably as they age. For shorter-lived species, researchers have used observable changes in behavior, such as the deterioration of web-building precision, to track the onset of senescence. The ability to monitor these arachnids over long periods provides valuable data on their natural history and survival strategies.