The invasion is silent. Without warning, they're everywhere: the kitchen, the living room, and even looking down at you while you sleep. Much like the plague of flies over the summer, there's a good chance your home is now overrun with spiders. While most spiders are solitary creatures, it might seem like there's a whole community of them hanging out in the corners of your rooms. On TikTok, British users are sharing unsettling clips of large spiders, some as big as tennis balls, taking a casual stroll across floors and walls. But why are spiders suddenly more visible? Are they getting larger, or is your house just shrinking? Metro spoke with Adam Hart, a professor of science communication at the University of Gloucestershire and known as the UK’s 'spider expert,' to find out. Almost all homes have spiders, with Tegenaria—those big, hairy ones commonly found in bathrooms—often called house spiders. They are inside because, like you, they are seeking safety. With no predators to worry about, your home is an all-you-can-eat buffet, filled with flies, moths, and other insects that spiders feast on. They also love clutter, such as cupboards, under the bed, or anywhere you've been meaning to tidy since 2020. According to Hart, we are not in the grips of a 'national spider population explosion'—at least, there's no evidence of it yet. However, we are in the beginning of 'spider season,' which runs from September to mid-October. During this time, male spiders leave their webs to search for females to mate with. "It can look as though they've suddenly invaded our homes," Hart explains, "but in many cases, they've actually been living in and around our houses quite unobtrusively for much of the year." What changes is their behavior. The large house spiders people are seeing running across floors are often mature males wandering in search of females. They suddenly become more mobile and noticeable, so we're seeing more spiders, but that doesn't necessarily mean there are more of them. September is also when the weather becomes rainier and windier, which can be dangerous for tiny spiders. Recent heatwaves in the UK may have influenced spiders' development and activity this year. "Anecdotally, I started noticing large house spiders slightly earlier than I normally would," Hart adds. Despite some TikTok users' claims, spiders aren't 'on steroids' this year compared to normal. The reason for the apparent size increase is simple: these are adult spiders, and their long legs make them look larger than they are. "A large male suddenly sprinting across a pale carpet can look considerably more impressive than a spider sitting quietly in a corner!" Hart notes.