Wildlife and public safety officials in western U.S. states have issued warnings as tarantula mating season brings a surge of spiders onto trails, parks, and residential areas from August through December.

The annual event has generated attention in California, home to 10 of the country’s 29 species, where experts urged the public to remain calm and informed rather than alarmed by the surge of hairy arachnids in the coming months.

Why It Matters

This annual increase in tarantula activity has sparked concern, particularly among those with arachnophobia, but large, intimidating-looking spiders pose little risk to humans. In addition to curbing insect populations, tarantulas contribute to soil health through their burrowing, and their presence signals robust ecological health in arid and semi-arid regions of the western and southwestern United States. Public advisories aim to reduce human fears and prevent unnecessary harm to both spiders and people during increased sightings and interactions.

What To Know

Male tarantulas emerge from their burrows to search for mates from August to December, often traveling up to 20 miles.

In California, common species include the Mohave blonde tarantula and the California ebony tarantula, found in regions like Joshua Tree National Park, the Mohave Trails National Monument, Kern County’s oak woodlands, and several Los Angeles parks.

Sighting probability increases after warm days and before seasonal rains, particularly at dusk and night.

Other states with prominent tarantula populations and increased activity during mating season include Texas, New Mexico, Arizona, Kansas, Colorado, Oregon, and Washington.

Tarantulas typically dwell in arid and semi-arid habitats, ranging from desert scrub to oak woodlands, and occasionally wander into developed or recreational areas.

Tarantulas, particularly males, display “highly visible behavior” during the mating months, leaving their otherwise secretive lifestyle behind to roam in search of females.

Contrary to popular belief, U.S. native tarantulas are not aggressive and rarely bite humans. They only bite if extensively provoked or mishandled, and their venom is not life-threatening, generally causing only minor pain or irritation.

However, tarantulas possess urticating hairs, which they can release as a defensive strategy; contact can cause skin irritation or rashes. Direct handling is discouraged, and experts recommend observing spiders from a distance.

What People Are Saying

Sarah Crews, a researcher at the California Academy of Sciences’ Department of Entomology, said in a Phys.org report: “The spiderlings probably hang out for a bit, then disperse and make their own burrows, likely not traveling too far.

Crews said that when a spider is scared by a predator, it will rub its hairs to ward off the danger.

“This is why you sometimes see tarantulas with ‘bald spots.’ They do it when they are stressed, so if you come across one and it starts doing that, best to leave it alone…while it won’t hurt humans, you don’t want to stress out the poor guy—he has enough problems at this point.”

What Happens Next

Tarantula mating season is expected to continue through December in most western states. Wildlife and park officials plan to maintain public advisories and encourage safe viewing practices, particularly in areas known for high sightings such as Joshua Tree National Park and the Santa Monica Mountains.