Some might say Americans are soon in for a peculiar and downright terrifying experience. That's because hordes of tarantulas will soon be descending across large portions of the country.
It might sound like an ominous sign of the apocalypse or a good reason to look for a new place to live, but this is actually perfectly normal. A yearly event, thousands of spiders seek out mates, particularly in Colorado, Texas, New Mexico and Arizona.
Of course, for anyone witnessing the event, it will be tempting to go on the offence. But just how easy are these swarms to deal with? And how much of a threat really are they?
Why are spiders swarming?
When it comes to large swarms of animals or insects, there are typically two main reasons it is happening. The first, and most ubiquitous, is migration. The second, the reason why the US tarantulas emerge, is love. But not exactly as we know it.
“Every year, male tarantulas come out in search of a mate. The females tend to stay in their burrows and emit pheromones to let males know where to find them,” Lauren Davidson, Associate Curator of Entomology at the Houston Museum of Natural Science, told BBC Science Focus.
“So, if someone were out during this time of year and saw a tarantula roaming around, it most likely would be a male. The males emerge when the climate is just right, so it is very dependent on the area where you live.”
The male tarantulas are typically only alive for one mating season; only the reproductively mature males actually go out to search for a mate.
When they’ve tracked down a female’s pheromones, the male tarantula will ‘knock at the door’. This involves tapping near the entrance in a drum-like pattern. If the female is intrigued, she will emerge to greet him.
Where are you most likely to see males? The tarantula’s mating season changes depending on the region. For Texas, it occurred in early summer whereas Colorado and New Mexico will likely see the event occur well into October.
“This event does happen every year, usually around the same time. If people haven’t noticed these large numbers before, then they likely won’t notice them this year either,” says Davidson.
“It is very cyclical and region-dependent. You really have to drive quite a way out of the city to see any of these males. Tarantulas are also nocturnal, so most of this is happening at night.”
While this might seem like migration due to the large numbers moving, the spiders are actually staying very close to home where they’ve always been, searching for mates. Overall, tarantulas will travel only around a kilometre from their home.
What should you do if you see one?
While it’s unlikely that you’ll bump into one of these tarantulas on the way to their date, it’s not impossible. So what should you do if they cross your path?
“These are very harmless spiders. I know that because they are big it gives the impression that they are dangerous to people. They are not. They can bite, but their venom is comparable to a bee sting,” says Davidson.
“Bites are rare though, as their first defence would be to run away. To them, we look like giant predators and they don’t want anything to do with us. Their second defence would be to kick urticating hairs from their abdomen.”
This sounds scarier than it is. The hairs can be very itchy or irritating when they come into contact with your skin. However, it would require you to be up close and personal with the spider.
“There are many people that travel just in hopes of seeing large numbers of these tarantulas. They are very docile, and people often handle them in the field without any incidents.”
About our expert
Lauren Davidson is associate curator of entomology at the Houston Museum of Natural Science. She is also the current manager of Cockrell Butterfly Center. She is the author of several kids' books, all focused on teaching children about entomology.
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