The lifespan of a spider varies dramatically, ranging from a single season to several decades, even among sexes within the same species. Spiders belong to the class Arachnida, which includes over 50,000 known species exhibiting an astonishing range of life expectancies. This profound difference in longevity is primarily dictated by the organism’s fundamental biology and the environmental pressures it faces.
The Wide Range of Spider Lifespans
The vast majority of spiders encountered belong to the infraorder Araneomorphae, often called true spiders, which typically have much shorter life cycles. Araneomorphs include familiar species like orb weavers, jumping spiders, and common house spiders. For most of these species, the lifespan is relatively short, often completing their entire cycle in one year or less, particularly in temperate regions.
In stark contrast, the infraorder Mygalomorphae, which includes tarantulas, trapdoor spiders, and funnel-web spiders, is renowned for its exceptional longevity. These spiders have a more ancient lineage and a different body plan, correlating with a slower life history. Female mygalomorphs can live for many years, sometimes taking years just to reach sexual maturity, a period that often exceeds the entire lifespan of true spiders.
Some female tarantulas can live more than 25 years in the right conditions. The record holder was a female trapdoor spider in Australia, estimated to have lived for 43 years before its study was abruptly ended by a parasitic wasp.
Biological and Environmental Factors Determining Longevity
A spider’s metabolic rate is a significant biological factor influencing its rate of aging and lifespan. Species with a longer life expectancy often exhibit lower resting metabolic rates compared to those with an annual life cycle. Cooler environmental temperatures typically reduce a spider’s metabolism, slowing down growth and development, which often results in a longer life, especially for burrowing species. Conversely, warmer temperatures accelerate life processes, leading to faster growth, earlier maturity, and a shorter overall life.
The difference in life expectancy between the sexes is one of the most pronounced biological factors. Male spiders almost universally live significantly shorter lives than females, often dying within weeks or months after reaching sexual maturity and mating. This disparity is due to the male’s singular focus on reproduction after its final molt, a process that often leaves them vulnerable. Female spiders, responsible for producing and guarding egg sacs, have a greater reproductive investment that necessitates a longer survival window.
Consistent access to food is necessary for survival, and the quality and quantity of the diet affect the pace of life. A high-quality, continuous food supply accelerates growth and speeds up the time to reach maturity, potentially shortening the life cycle. Interestingly, periods of dietary restriction have been shown to increase the lifespan of some male web-building spiders by reducing their metabolic activity.
Molting is a vulnerable and energy-intensive process that must occur repeatedly throughout a spider’s juvenile stages. For many true spiders, molting ceases once they reach sexual maturity, but female mygalomorphs can continue to molt well into adulthood. This post-maturity molting is sometimes linked to nutritional conditions and can lead to an increase in body size and a longer lifespan, contributing to the remarkable longevity observed in the mygalomorph group.
Comparing Common Spider Lifecycles
Many spiders in temperate zones, such as the common garden orb weavers, are classified as annual species, completing their life cycle within a single growing season. The female typically lays an egg sac in the late summer or fall, and then dies as the weather cools. The next generation overwinters as eggs or tiny spiderlings, emerging the following spring to restart the cycle.
Common house spiders, including cellar spiders and various cobweb spiders, often experience a different longevity trend due to their indoor habitat. Living in climate-controlled environments shields them from the harsh seasonal changes that limit outdoor species. These indoor spiders often live longer than their outdoor counterparts, typically surviving for one to three years, with some species like the barn funnel weaver occasionally reaching up to seven years.
At the extreme end of the spectrum are the long-lived mygalomorphs, such as tarantulas. Female tarantulas commonly live between 10 and 20 years, with some species exceeding 30 years in captivity. Male tarantulas live only a fraction of this time, usually maturing in a few years and then surviving for just a few months to a year after their final molt.
When spiders are kept in captivity, their potential lifespan is often maximized due to the stable environment. Consistent temperature, controlled humidity, and a reliable food source remove the major sources of mortality found in the wild, such as predators, starvation, and extreme weather. This controlled setting allows species, particularly the long-lived mygalomorphs, to reach the upper limits of their genetic life potential.