Wednesday, October 25, 2023

Curiosity 4: Scorpions

We went for an afternoon hike today at Garrapata State Park, 15 miles south of us on the coast. Our goal was to find two geocaches that had been eluding us—and we did! So now that area is all smiley faces and we never have to go back! Because the hike is a real bear: steep up and, consequently, steep down. Still, it's a beautiful place and we had perfect weather: mid-60s, a nice breeze, clear skies, making for great views.

Along the way we saw many western fence lizards (Sceloporus occidentalis), what I'm guessing was a juvenile skink with its bright blue tail (Plestiodon sp.), a desiccated deer carcass, and, under a rock (still looking for geocaches), a scorpion! I'm guessing it was a California common scorpion (Paruroctonus silvestrii). 

That of course got me wondering: how many species of scorpion are there? Wikipedia tells me there are over 2,500 species, in 22 families, on all continents but Antarctica. Fun facts: Scorpions' exoskeletons contain fluorescent beta carboline and glow under ultraviolet light—which includes moonlight. The "glowing" is actually a way of reflecting the UV light, perhaps a protective mechanism from when scorpions were first on the planet, over 400 million years ago, and oxygen levels were low and UV light from the sun intense. Scorpions are nocturnal. Only a couple dozen species have stings venomous enough to seriously injure or kill a human. When scorpion babies (scorplings) are first born, their exoskeletons are soft, and their mama carries them on her back until they harden.

The more I study their anatomy, the more... impressed I am that a creature like this could even exist. Key: 1 = Cephalothorax or Prosoma; 2 = Abdomen or Mesosoma; 3 = Tail or Metasoma; 4 = Claws or Pedipalps; 5 = Legs; 6 = Mouth parts or Chelicerae; 7 = pincers or Chelae; 8 = Moveable claw or Tarsus; 9 = Fixed claw or Manus; 10 = sting or Aculeus; 11 = Telson (anus in previous joint); 12 = Opening of book lungs

A scorpion, by the way, has one pair of eyes on the top of its prosoma, and two to five more pairs on either side. If it weren't for the claws extending from the cephalothorax, I could almost buy that it has a head...

This is a quick entry, because I'm beat, and ready for some ice cream and TV (Great British Baking Show, perhaps?). But now I know a little more about scorpions than I did this morning, and that's a good thing. 

Here are two photos from our loop hike: overlooking the Pacific and on the way back through a redwood canyon. I will spare you the deer carcass, though it's actually pretty cool.

And the sea of smileys, with an idea of the steepness of the terrain (our elevation gain today was just shy of 2,000 feet, over the course of a couple of miles):


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