Upper Left: Black Widow; Photo Credit: Paul Johnson, NPS
Upper Right: Tarantula; NPS Photo
Bottom: Jumping Spider; Photo Credit: Paul Johnson

There are likely hundreds of species of spiders in San Francisco Bay Area Network parks, but they have never been completely inventoried. Spider species at Point Reyes National Seashore include the crab spider, the red-backed jumping spider, and a tiny orb weaver that hides amongst debris in its web. At Pinnacles National Park, spiders include the highly poisonous but timid black widow, the green lynx, which hunts on flowering shrubs, and tarantulas.

The best times to see tarantulas at Pinnacles National Park are September and October, when the males are out searching for mates day and night and are commonly seen crossing roads. Males investigate every potential burrow until they find a female that is ready to lay eggs. While male tarantulas die within a year of mating, females can live more than two decades. During the rest of the year, these large hairy spiders spend the days in small silk-lined holes in the ground, emerging to hunt only at night.

Tarantulas are a key part of the food web, preying on insects and other invertebrates and possibly even lizards, snakes, and small rodents. In turn, tarantulas are eaten by lizards, snakes, birds, and tarantula hawks. The largest spider wasps, tarantula hawks are nearly as big as hummingbirds and have shiny blue-black bodies with smoky orange wings. Female tarantula hawks sting a tarantula to paralyze it and then drag it to a hole, where they lay eggs in and then bury the tarantula.

Tarantulas raise their front legs and abdomens to look aggressive when alarmed. While they may bite people in self-defense, much like a bee sting, these gentle spiders rarely use their fangs except to catch prey. Park staff recommend close-focus binoculars as a handy way to get a closer look at tarantulas and other invertebrates.