How big will spiders be 50 years from now?

Answer 1

Spiders have been around for some 300 million years, and they have changed very little since they evolved. Their sizes have not changed during the period that humans have been making written observations about them. Sometimes new spiders come to the attention of scientists who may document things that people who live in the area where the spiders are found have always known. For instance, there has been some interest in recent years in a Huntsman spider found in South East Asia that has a leg span almost as large as the largest known tarantulas, but these large spiders did not suddenly pop into existence sometime in the last few decades or centuries.

So unless something very strange and almost impossible happens in the next fifty years, spiders will not get either larger or smaller.