It's Tarantula Mating Season in the Bay Area: Here's Where to See Some Fuzzy Friends

If you’ve been hiking in the East Bay hills or places like Mount Diablo, you might’ve noticed more tarantulas than usual. That’s because it’s tarantula migration season, and it’s when these fascinating eight-legged, hairy creatures come out to mate. Tarantula mating season here in the Bay Area typically starts in mid-September and peaks around mid-October.

But fear not, although tarantulas might look creepy, they’re harmless creatures and are afraid of humans. They’re actually trying to get away from us. Because they can “hear” with their feet — they don’t have ears but nerves that can detect sounds like footsteps from a distance and will try their best to go in the opposite direction.

Spiders are highly adaptable creatures and are an incredibly important part of our ecosystem, said Lauren Esposito, curator of Arachnology at the California Academy of Sciences. Esposito runs a research lab at the academy that studies the evolution of arachnids, including spiders, scorpions and more.

Unlike some other species of spiders that use silk to build webs to capture prey, tarantulas use their silk to create a mat that they use as a sensory extension system, which allows them to hear with the tiny organs in their feet when they’re standing on the silk.

She said the spiders you might see crawling around during this season are almost entirely male tarantulas looking for a female burrow, a den that looks like a hole that the spider dug in the ground with its fangs.

“The way that they identify [the female tarantulas] is by smelling the silk,” said Esposito.

The female tarantulas live in their burrows almost their entire lives and very rarely come out. Because they have that nice silk mat, they can sense when an insect walks by and scurry out to grab it before retreating to the safety of their burrow.

The females lay down pheromones or chemical signals that indicate to the males that they’re of the same species. And as the male approaches the female’s burrow, he’ll smell the silk to make sure he’s on the right track. He’ll then communicate with the female by tapping on the silk, which she can hear with the “ears” on her feet.

If she doesn’t react aggressively, it’s usually a signal that the male may enter her burrow, an invitation to mate.

Afterwards, he’ll leave. “He doesn’t hang around and goes back to construct his own burrow and resume his life for the rest of the year,” said Esposito.

Once she’s mated with the male, the female tarantula will lay eggs that are fertilized, and those eggs will stay down in her burrow. The young hatch and emerge sometime in the spring. They’ll soon leave and start digging their own burrow somewhere in the ecosystem nearby.

For the past 300 million years, spiders of all kinds have managed to find adaptations that enable them to survive and thrive in virtually every ecosystem on Earth.

“There are spiders that live completely underwater. Spiders that live in the desert, like in Death Valley. There are spiders that build webs in the canopy of trees and other spiders that only build a tiny, teeny, web in between fallen leaves on the forest floor,” said Esposito.

Some of the best places to see tarantulas around the Bay Area are in the region’s grassy oak woodlands. They tend not to be in the redwoods or more densely forested areas in as high numbers, according to Esposito.

A few places where you might be able to spot tarantulas are Del Valle, Sunol Regional Wilderness, Mount Diablo, Henry W. Coe State Park, Black Diamond Mines in Antioch, Ed R. Levin Park, and the Stanford Dish Loop trail.

For those eager to learn more about these fuzzy friends, a few events to look out for to join others in searching for tarantulas include: Coe Park Tarantula Fest on Oct. 7 at Henry Coe State Park and East Bay Regional Park District Tarantula Trek in Del Valle Regional Park on Oct. 1.