With autumn upon us, the time to catch tarantulas in their migratory meanderings has arrived. Otherwise nocturnal, mature male tarantulas abandon their burrows during the daytime this time of year (typically September/October) in advance of the creeping onset of cold weather to look for mates. When they find a female, they lure the eight-legged lady from her lair and, using their tibial hooks – a spur-like appendage grown on each front leg during their last molt – they restrain their partner’s fangs while they mate to keep from being stung and eaten. Afterwards, the female returns to her burrow to lay her silken clutch of eggs, while the male continues in search of other females until he succumbs to the cold weather.
Although tarantulas can bite, delivering a sting likened to that of a bee, their venom isn’t dangerous to humans. Instead, when threatened, tarantulas usually adopt a defensive pose, raising up on their front legs to brush urticating (stinging) hairs off their abdomen with their hind legs in the direction of an intruder.
Each year, this match-maker melodrama plays out throughout California and, in the big picture, across North, Central, and South America where the Aphonopelma spp. tarantulas are found. Here in the Bay Area, however, Mount Diablo is one Mecca where tarantulas can be found in numbers without too much trouble, as I was fortunate enough to experience last week at Mount Diablo State Park‘s Mitchell Canyon. The male pictured here was one of four already on the prowl. If you look closely at his front legs (not the leg-like pedipalps; in the photo above, look at the leg extending into the bottom-left-most corner of the image), you will see the spur on the underside of the third leg segment – that’s the tibial hook!