Curiosity 47: Tarantulas

My sister-in-law Patty and I have started meeting every couple of weeks to share and critique writing. It's great! It's really hard (for me) to write in a vacuum (and not just for me, I suspect). So getting her work to read and think about, and her eyes on my stumbling-along attempts at essays and (maybe?) a novel, is super helpful. And stimulating. And fun!

Currently, she is working on an essay about spiders. And she mentions tarantulas—one with an 11-inch leg span (yowza!) and another "purple pink-toed" one. Which got me curious about tarantulas generally. So here ya go.

When I search for tarantulas, Google greets me with a list of (I guess?) the most commonly asked questions, such as:

What is the least poisonous tarantula? A: The best beginner spider to keep as a pet would be a tarantula such as the Chilean rose, Mexican redleg, or Costa Rican zebra. These species aren't terribly venomous and are pretty docile when compared with some other tarantulas (their venom is comparable to bee venom). The Brazilian black and the pink toe are also included with these three in response to queries about "the easiest to care for" and "most docile." In case you were thinking of getting a pet. Much easier to leave behind than a dog or cat when you go on vacation. (In captivity, tarantulas only need to be fed once a week or so, and some have survived up to two years on water alone.)

That dinner plate–sized tarantula, the Goliath birdeater—the largest spider by mass, weighing 6.2 ounces—makes a good pet too. It also makes good eating, apparently, and is a delicacy in some parts of South America. (It tastes like shrimp.) And yes, it does eat (small) birds, as well as lizards, mice, bats, and small snakes. If you keep one at home, though, it won't turn up its nose at insects.

There are 1,040 species of tarantula all told, in 156 genera, all in the family Theraphosidae. Most North American tarantulas are brown. I found one last week on a trail, and it was a lovely light brown, almost blond. But they also come in cobalt blue, black with white stripes, with yellow leg markings, and—this one I would love to see—with metallic blue legs, vibrant orange abdomen, and green prosoma (or cephalothorax). And it's got an impressive name to match: Chromatopelma cyaneopubescens, aka greenbottle blue tarantula. (It's actually more muted than the above description suggests, but still: what a stunning spider! ⤊ It lives in Venezuela and is endangered, its habitat being decimated by overgrazing and fumigation.)

And that purple pink-toed number, which happens to hail from Peru, is one of a dozen in the genus Avicularia, all with pink toes. (The one shown here is a male A. juruensis.)

The biology of tarantulas is too vast, and bizarre—like how they have sex!—to detail here (but it's fascinating, so go to Wikipedia and read all about it), but here are just a few random fun facts:

• Tarantulas are either arboreal or terrestrial; those living in trees tend to shelter in silken "tube tents," while the land-based ones dig burrows. 
• Each of their eight legs has seven segments: coxa, trochanter, femur, patella, tibia, tarsus and pretarsus, and claw (counting from the prosoma outward). They also have two additional, specialized pairs of appendages, used in feeding, gripping prey, and—what did I tell you?—sex.
• Males tend to be smaller (especially their abdomens) and have longer legs than females.
• Females can live for 30–40 years. Males live only 7–10 years. As one site explains, "Once they reach sexual maturity, some males become so focused on mating that they stop eating. With the extra energy required to find mates and produce sperm packets, this can lead to starvation."
  
• Females deposit 50–2,000 eggs, depending on the species, in a silken egg sac, which they guard for six to eight weeks. In most species, the female turns the egg sac often, to keep the eggs from deforming. (Ah, amazing instinct!) 
• A tarantula has eight eyes, like most spiders, but touch is its finest sense.