A rare and mysterious migration is now underway across parts of the American Southwest — and it’s happening right underfoot.
Every year from late summer into fall, thousands of male tarantulas leave their burrows and begin a dramatic journey across deserts, grasslands, and sometimes even suburban neighborhoods. Their goal: find a mate before time runs out.
According to experts, the sudden appearance of these large, slow-moving spiders can startle residents who aren’t expecting it. But behind the scenes, it’s a once-in-a-lifetime event for the tarantulas themselves — and one that always ends the same way.
“These males… they’ve been alive for five to eight years,” said Cara Shillington, a biology professor at Eastern Michigan University who studies tarantulas. “They have one mating season. At the end of the season, they will die.”
That means if you see a tarantula on the move between August and October, you’re likely watching the final chapter of its life. After spending years underground in a quiet, solitary existence, this is its one chance to reproduce before its journey ends.
If you’re scared of spiders, look away. 🕷️
Thousands of tarantulas are getting ready to search for love as mating season kicks off in August. Here’s where they plan on going. https://t.co/29xEBN8kE8 pic.twitter.com/Q3qKF3FHmY
— Yahoo News (@YahooNews) August 2, 2025
This natural behavior isn’t new, but more people are noticing it thanks to growing interest in outdoor activity and social media, where images of fist-sized spiders marching across roads or trails often go viral.
The migration is most noticeable in Southern and Southwestern states, especially in:
– Texas
– Arizona
– California
– Oklahoma
– New Mexico
– Nevada
– Utah
– Southeastern Colorado
In fact, the movement is so well-known in southeastern Colorado that the town of La Junta hosts a Tarantula Festival each year to mark the occasion.
Paul Biggs, a board-certified entomologist with Orkin, explained that tarantulas spend most of their lives hidden. “They are less active during the cooler months, spending this time dormant in their burrows,” he said.
Once temperatures rise and conditions become just right, they emerge. The males begin their search — often walking long distances through unfamiliar terrain in search of a female hidden in her burrow.
Shillington said it’s unclear how they know where to go or how far they travel. “We actually know very little,” she admitted. “I don’t know when exactly they first come out or what prompts them.”
Despite their size and appearance, tarantulas are not dangerous to humans. Shillington noted that they are “more scared of you than you are of them.”
They rarely bite, and when they do, it’s usually a last-resort reaction to being grabbed or cornered. Their bites are not considered medically serious for most people, though they can be painful.
So what should you do if you see one in your yard or even inside your home? Experts recommend staying calm and avoiding contact.
“Any time you try to grab it, the first thing it’ll do is try and run,” Shillington said. “They respond to anything trying to grab them as a threat.”
If one ends up indoors, she suggests gently trapping it in a large container and releasing it outside.
Biggs also cautioned against using chemical pest products, which could cause more harm than good. “If you can contain it to one area in the meantime, do so without physically handling it,” he said.
Scientists continue working to better understand tarantula behavior — how far they travel, what triggers their migration, and what environmental factors affect their movement.
For now, those in tarantula territory are being urged to be alert and aware, especially during this brief and unusual season when the spiders are most active.
It may be unnerving, but it’s also a rare chance to witness a unique natural event that only happens once in a spider’s lifetime — and just once a year for everyone else.
