How Old Are Spiders?
WouterThe length of a spider’s life is determined by species, and some species can live more than a year. Female spiders generally have a longer lifespan than males. They are responsible for laying eggs and protecting them. However, they don’t carry pregnant spiders.
Arachnids, which includes spiders, are among the oldest animal groups to have lived on land. At least 420 million years ago, arachnids began to diversify.
During the Devonian period, some of the earliest dinosaurs were known, and tetrapods, which are four-limbed animals, began to form. Eventually, they evolved into mammals, reptiles, and amphibians.
Scientists have recently discovered a 305-million-year-old arachnid fossil in France. This arachnid was a member of the uraraneid family, which was closely related to true spiders. It lacked the spinnarets that are characteristic of true spiders, but it could produce silk.
Scientists also found the fossil of a tarantula in Mexico. It lived for over 30 years, making it the longest-lived tarantula known to date. Researchers tracked it as it grew older.
Female tarantulas tend to live longer than males. In general, males die soon after mating. Male spiders also molt less than females.
Some species can produce hundreds of spider eggs in an egg sac. These eggs hatch within a few weeks in good conditions. During cold months, however, they may wait for cooler weather to complete their hatching. Once they are hatched, the baby spiders cling to nearby plants and use their newly-formed legs to escape.
