Sally Lightfoot Crab
Grapsus grapsus or Percnon gibbesi
(the two species most commonly referred to as SLC)
First we’ll look at Grapsus grapsus, because, let’s be honest, that’s a pretty rockin’ species name! I’ll call her Sally G.
How beautiful is this crab!? Grapsus grapsus in the Galapagos.
Sally G roams along the west coast of Central and South America. However, she is most well known as the beautiful red rock crab inhabiting the Galapagos Islands, as recorded by Charles Darwin! There, the Sally G’s munch on algae and different dead animals like fish, birds, and even seals! That may seem pretty viscious, but it’s a tough environment for these little crabs, being preyed on by the likes of feral house cats.
something tells me this iguana isn't as into snuggling as the Sally Lighfoot crab
G. grapsus does have supporters though: John Steinbeck wrote about Sally G crabs in his Log from the Sea of Cortez (a great read!), and, while we’re dropping names, Martha Stewart is an admirer, having printed Sally G on fun towels for her Galapagos collection.
What about Sally P, aka Percnon gibbesi? This crab has been called “the most invasive species in the Mediterranean”! (And that’s saying something, as it’s one of 13 invasive decapods crustaceans recorded there.) But that just means Sally P is one hearty crab. She ranges from California to Chile and Florida to Brazil, not to mention from Madeira, Portugal (off the Moroccan coast) to the Gulf of Guinea along the west coast of Africa!
Percnon gibbesi nestled into some nice coral
Sally P has beautiful coloration and stripes on her walking legs, which I thought might explain another nickname of P. gibbesi: the urchin crab. I was wrong. Sally P can be found most often in the company of long-spined urchins, using their spines as protection from predators. And the urchins don’t have to worry, because unlike Sally G, Sally P is a vegetarian, eating primarily algae and detritus.
Sally P and its urchin guardian
Now that you know Sally Lightfoot, feel free to introduce them to your friends at parties. Consider yourself on a first name basis.