With the help of their webs, spiders are capable of foresight, planning, learning and other smarts that indicate they may possess consciousness

NHPA/Photoshot

THERE is an alien intelligence living among us. These creatures possess an extraordinary kind of consciousness, including minds that extend beyond their bodies. Yet, thanks to our ignorance and arrogance, our immediate impulse is to kill them.

This is no fantasy. These alien minds really are lurking in the shadows of our houses and gardens: spiders. We have long assumed that, like many invertebrates, they are little more than automata, lacking an inner life. But we are now discovering that some arachnids possess hidden cognitive abilities rivalling those of mammals and birds, including foresight and planning, complex learning and even the capacity to be surprised. Stranger still, the delicate silk threads they spin out behind them, so easily swept up by a feather duster, help them to sense and remember their world. Indeed, spiders’ silk is so important to their cognitive abilities that some scientists believe it should be considered part of their mind.

Now that we are starting to appreciate spiders’ intellectual capabilities, we must surely change how we see one of the most ubiquitous, important and vilified groups of animals that has ever evolved. What’s more, these incredible creatures could also challenge our understanding of our own intelligence and minds.

Spiders have deep evolutionary roots. The earliest fossil evidence of silk-producing arachnids dates from almost 400 million years ago, shortly after the first definitive evidence of insects. “Insects are the most successful lineage on Earth, but spiders pretty much follow them,” says evolutionary biologist Miquel Arnedo at the University of Barcelona, Spain. Today, there are more than 48,000 known species, with every square metre of land …