It’s mating season for the hairy tarantulas in the Santa Cruz Mountains

In the waning sunlight near the Stanford Dish and in the open fields in the hills, a hairy spectacle is taking place. In the ground under the tawny grasses, male California tarantulas are emerging from their underground lairs in search of mates.

The large, hairy spiders slowly crawl along the ground seeking the nests of equally hairy females, guided by scent. When he finds one, the male will tap the ground seductively with long, front legs outside her burrow. Sensitive to vibrations in the ground that might signal the presence of prey, danger or a suitor, the female will tap back a reply.

She’ll emerge from her bedchamber to inspect her suitor. If she is agreeable, she’ll let him mate.

But suitor beware. If she doesn’t like him, the larger —‌ and usually hungry —‌ female will likely eat him, said Jack Owicki, a Midpeninsula Regional Open Space District docent and naturalist.

August to October is tarantula mating season in the Bay Area. Along trails and in fields, dozens of the arachnids seek out mates in the late afternoon and through the night when they prefer the cooler hours and, perhaps, the cover of darkness.

That’s when Owicki, a retired scientist, finds them. In the years before the COVID-19 pandemic, he led Arachnophilia, a nighttime spider hike, for the open space district, including tarantulas.

Although sometimes thought of as denizens of the drier East Bay hills, tarantulas are equally common in the Santa Cruz Mountains. Nature enthusiasts can find them in many of the Midpeninsula Open Space preserves and in Palo Alto’s Foothills Park. The burrows are lined with white spider silk, a corolla of the sticky substance extending out of their entrances. The holes range from the diameter of a dime to a quarter, Owicki said.

Inside, the black, gray or brownish spiders can have a body length of up to 5 inches long in California and a leg span of 4.5 inches, according to the advocacy group Los Padres ForestWatch. Males are smaller than the females. They reach adulthood when 8 to 12 years old, when they mate. The males will usually die within a year of adulthood and shortly after mating; females can live up to 25 years, according to SaveNature.org.

Often portrayed as jumpers and ferocious attackers in scary Halloween props, tarantulas, despite myths, are not aggressive. They won’t generally bite unless they are provoked and they won’t run after people, Owicki said. The bite is also not medically significant, unlike that of the black widow spider. Still, a tarantula’s bite is likely to hurt on the magnitude of a bee sting, he said.

The dangerous tarantula myth might in part be derived from stories about another spider with a similar name. In southern Italy, the wolf spider, or “tarantula,” a large arachnid found near Taranto, was thought to give its victims a venomous bite that caused convulsions. Victims who performed a dance called the tarantella to certain types of music were said to be cured, according to the American Tarantula Society. The wolf spider isn’t a tarantula -—‌ it is in a different family of spiders —‌ and its bite isn’t lethal. It is said to be equally as painful to the tarantulas, though.

Tarantulas have another interesting defense besides the bite: “On the back of their abdomen they have spiky, barbed hairs that are attached loosely,” Owicki said. The spiders use these hairs quite effectively and lethally against mice that sometimes attack them. When the tarantula vigorously rubs its back legs on its abdomen, the hairs form a cloud. As the mouse inhales them, “they are like nettles the mouse gets in their lungs and they die,” he said.

The hairs, while not deadly to humans, can cause discomfort.

“If they get on you, you’ll get a rash,” he said.

The U.S. has 29 distinct species of tarantulas, 10 of which are in California, according to literature from Los Padres National ForestWatch. They are found mainly in the southwest and some central states.

Since mating is a tricky business for tarantulas, the male, once it appears he won’t be devoured by his potential mate, will tentatively stroke the female’s body. He’ll use two short legs with what looks like boxing gloves, or pedipalps, to insert a wad of silk containing semen, he said.

Before that feat is accomplished, the males must again protect against being devoured. Some males first insert thick spines on their front legs between the female’s fangs to keep her from delivering a deadly bite, he said.

Tarantulas maintain an important ecological niche, eating grasshoppers, beetles, plant-eating insects and sometimes small lizards. In turn, they become food for lizards, snakes, spider-eating birds, coyotes and foxes, according to the Arizona-Sonora Desert Museum. The tarantula hawk, a spider wasp, paralyzes the tarantula and drags it into its nest so its offspring have a fresh meal to feed on when they hatch.

Humans, too, can contribute to a tarantula’s demise through pesticides and land uses such as development and farming. But even the curious can unwittingly destroy a tarantula. Unlike hard-bodied insects, dropping a tarantula from even from a height of only 3 feet can kill them, Owicki said.

Besides the tarantula, hikers might encounter another slightly smaller spider: the Calisoga, or “velveteen tarantula.” It is not a true tarantula and is in a different spider family, Owicki said. If encountered, Calisogas have a reputation of being a little more defensive, he added.

To the touch, Calisogas have a soft sheen. Tarantulas are a bit coarser, Owicki said.

The tarantulas are a popular fall attraction in some parks. In Santa Clara County, Henry Coe State Park has an annual TarantulaFest this time of year. It’s been called off for 2020 due to the COVID-19 epidemic and the SCU Lightning Complex fires, which swept through the area, according to the park’s website.

There are plenty of opportunities to bump into tarantulas his month, but it’s best to just leave them alone.

“Watch it respectfully. Marvel at the very different way of living from a mammal’s way of living,” he said.