Tinder meets tremors as Western tarantulas look for love
Males will travel in numbers, dance hypnotically and get eaten during their annual hunt to mate.
This story is published with the Guardian as part of their two-year series, This Land is Your Land, examining the threats facing America’s public lands, with support from the Society of Environmental Journalists.
Gaggles of tarantulas are emerging from their burrows across the Western U.S. on a quest to mate, hunting for love in prairies, foothills and a garage belonging to Kim Kardashian West.
From August to October, the eight-legged crawlers go on a walkabout for a once-in-a-lifetime foray to find a partner. The phenomenon is now occurring on a unusually large scale from northern California to Colorado and Texas, shining a light on the arachnids’ remarkable mating behavior, which can involve dancing and cannibalism.
For the first five to eight years of their lives, males live in a burrow, eating insects and maybe a mouse or snake. Tarantulas are wait-and-see predators; it’s quite a solitary life. “Then one day, they just pick up and leave in search of a willing female,” said Ana Cholo, a National Park Service public affairs officer who keeps a tarantula as a pet.
Male tarantulas aren’t mature until they reach age five, or eight, or 10 –depending on the species, said Forest Urban, manager of the invertebrate program with the Natural History Museum of Los Angeles. “Typically in all of spiderdom, males are much smaller and don’t live very long at all compared to females,” he said, which can make it to age 30. One reason for the size differential is that it takes a great deal of metabolic energy for females to produce and carry eggs, far more than it costs males to produce sperm.
Each year, starting in the late summer, it’s a guys week out, if you will. “Ding dong, it’s time,” said Urban. “All of a sudden, the eight-to-12-year-olds, they’re like, ‘Hey, let’s get together, let’s go to the bar.’ ”
Both sexes are blind – they can only detect light and dark – so this foray across the open range each evening is filled with danger. That’s one reason they team up. Predators like birds or tarantula hawk wasps are likely to only grab a few meaty tarantulas as snacks, and the rest can continue on their mission.
Because they spend most of their lives underground, tarantulas don’t have many defenses, but they can bite or flick hair from their abdomens on to predators, causing itching and burning. When they’re out in the world, it’s a numbers game. The more they stick together, the more likely it is that one of the crew is going to score.
Urban sounded mind-boggled by the difficulties they face, “without a map, blind, at night, for miles, and you only have a certain number of days to do this before you’re going to die.”
To find a female in a burrow about a foot underground, the male tries to detect vibrations. If he somehow succeeds, he’ll tiptoe in or knock on the web covering her burrow. His genitalia – known as a pedipalps – are right by his face, like two boxing gloves. “They use this glove-like apparatus to dispel sperm, and then it deflates like a balloon,” says Urban. After laying down a layer of sperm over silk web, the male heads for the hills – because if he lingers, the female will usually eat him.
Different species of tarantulas have developed ways of managing the fraught moment when the male encounters the female. “Some do a dance to try to hypnotize the female so she doesn’t strike,” Urban explains. “Others will drum their pedipalps to create a beat. Some will literally do a dance routine that looks like the YMCA.” As for the female? “She’ll just sit there like, uh, really dude? And more times than not, he gets eaten.”
Her hunger sated, the female will deposit her eggs on the sperm mat and bundle it up into a waterproof cocoon. Around three months later, she will have up to 1,000 spiderlings.
Even if the male isn’t gobbled up, his days are numbered. Males typically die within six months of mating.
For a female, making eggs is so energy-intensive that once she makes her cocoon, she won’t be able to do it again for another three years.
Tarantula sightings have seemed high this year compared with previous mating seasons, said Urban. Kim Kardashian West, who lives in Calabasas, California, posted photos to Instagram of three tarantulas she found in her garage. “It’s mating season,” she observed. Kardashian has been terrified by tarantulas on a previous occasion.
Even if they’re jolting to see, whether from excitement or fear, experts don’t recommend picking one up – not because they will hurt people but because tarantulas have a thin exoskeleton and can be injured if they fall.
Of course, that’s nothing compared with being consumed after sex.
Katharine Gammon is a freelance science writer based in Santa Monica, California. Email High Country News at [email protected] or submit a letter to the editor.
