There are so many interesting parts of tarantulas, and even as a tarantula owner of several years I am still learning!

It wasn’t until I got my little sling, Blinky, that I knew that there was such a thing as a “mirror patch.” Blinky was just a pale pea-sized spider when I first got them, so there wasn’t much to see. However as they started to molt and grow, I became very curious about a black spot that was on their back – it turns out, it was the mirror patch!

Spidey has a mirror patch, too, however her is much less visible because it her hair is darker. However, in certain lighting I can certainly see the iresdescent coloring and sheen of it, signifying this is where her urticating hairs are. You will know it’s a mirror patch by the way it reflects light – it will look “shiny” almost like a mirror!

Not all tarantula species have a mirror patch, so don’t be alarmed if you can’t find one on your tarantulas. Mirror patches are exclusive to a few New World species. Old world tarantulas do not have a mirror patch due to the absence of urticating hairs. Some New World species of tarantulas that do have a mirror patch are: Cyriocosmus, Euathlus, Grammostola & Paraphysa.

There’s not much information about why tarantulas have a mirror patch, however the most probably theory is that this is a warning to predators or some defense mechanism. A predator might see this reflective surface and either be deterred because it doesn’t look like the spider would make a good meal, or draw attention to the urticating hairs that would not be pleasant to encounter.

Mirror patches are a beautiful part of the tarantulas who have it. If you get a good picture of your spider with their mirror patch shining, it’s very precious!