Zip up your tents, Coloradans – the tarantulas are coming

Thousands of hairy arachnids are about to begin their annual trek across southeast Colorado (Image credit: FluidMediaFactory)

An army of eligible bachelors is about to start making its way across southeastern Colorado, good news if you like your suitors to have eight hairy legs. The annual tarantula trek is expected to begin in late August and last through October as mature tarantulas seek a mate.

Each September and October, when the temperatures drop but before a winter frost sets in, untold numbers of male Oklahoma Brown tarantulas begin their quest for love in the area. Setting out around dusk, tarantulas on the prowl can trek up to a mile across the Comanche National Grassland in search of a mate, and the hunt is treacherous – hundreds will be killed by the wheels of passing cars driven by unaware drivers before they find a mate.

Female tarantulas, meanwhile, have it easy – they burrow underground until a suitable mate comes along. When they find a match, there’s no wining and dining, at least until after the act. They’ll come up and get down to business without much courtship. Upon completion of intercourse, the female will try to kill her partner so she can eat him. In about a third of cases, she will succeed, but even when she fails, he will be dead by winter .


(Image credit: graphmaster)

It’s not exactly a romance novel, but the spectacle does draw hordes of onlookers to the area, hoping to get a glimpse of the bizarre sight of hundreds of hairy spiders on the prowl. So much so, in fact, that the town of La Junta, which christened the phenomenon the Tarantula Trek, launched the first annual Tarantula Festival for spectators in 2022.

Despite their cinematic representation, Oklahoma Brown tarantulas, also known as Texas Brown tarantulas, do not pose any great risk to humans. A bite from one has been described as similar to a wasp sting, and would be harmless in the exception of an allergic reaction. Fully grown, they can reach leg spans of up to four inches and weigh more than three ounces – about the weight of a small apple.

If you’re hoping to get a glimpse of this year’s tarantula march, bring a headlamp for patrolling the grasslands after dark, read up on how to keep insects out of your tent and watch where you put your hiking boots.

Julia Clarke

Julia Clarke is a staff writer for and the author of the book Restorative Yoga for Beginners. She loves to explore mountains on foot, bike, skis and belay and then recover on the the yoga mat. Julia graduated with a degree in journalism in 2004 and spent eight years working as a radio presenter in Kansas City, Vermont, Boston and New York City before discovering the joys of the Rocky Mountains. She then detoured west to Colorado and enjoyed 11 years teaching yoga in Vail before returning to her hometown of Glasgow, Scotland in 2020 to focus on family and writing.