Many of you know that I have spent hours and hours hand selecting the perfect decor for my chilean rose hair’s tank, as well as taken tons of time to design it for her – and in the end, I know I’m probably just doing it for myself. Spidey, my tarantula, has NO idea of the things I do for her, despite my pretending that she does.

So it makes me curious – can Spidey even SEE the toys and objects in her enclosure? How do tarantulas and spiders observe the world around them? Why, despite having so many eyes, are they thought to be so terrible?!

I’ve spoken before about how tarantulas and spiders mostly rely on vibration, touch, and taste to find food and make sense of their surroundings. As far as the usefulness of their eyes, it is thought that they aren’t much use aside from being able to detect changes from light to dark, which may help them with web building, hunting or hiding from predators.

However, there are some spiders who possess better eyesight than others. Unfortunately it’s not tarantulas. In fact, they are the nerds of the arachnid kingdom and their eyesight is likely the worst! It’s actually the smaller spiders that excel in this area. Many of them are “the day active jumping spiders (Salticidae) and flower spiders (Thomisidae), and the wolf spiders (Lycosidae) and net-casting spiders (Deinopidae).” And here’s another cool thing – they have different TYPES of eyes and they do very different things!

Most spiders have 8 eyes (some have 6), and these eyes are usually displayed in 2 rows at the front of the spiders’s carapace. These two rows are the anterior and posterior, and the eyes have the roles of either being a lateral or median eye. The anterior median eyes (also known as direct eyes) are very different from the others, known as indirect eyes. Direct eyes appear dark, while the others might look like they have a layer of light reflecting crystals and may take on a silvery appearance. The indirect eyes are able to see low light intensities. Spiders with good vision usually have larger indirect eyes.

As far as the lenses themselves, spider eyes see extremely bright images, however their retinas only create “coarse-grained mosaics of receptor cells” and they see at a lower resolution. Their eyesight if worse than the human eye, so it’s proven that our spiders can’t enjoy the enclosures we make them in the same way.

Some spiders have reflector eyes (wolf spiders). These spiders need large posterior eyes to help them hunt in the dark. These eyes help them spot movement even when there’s very little light.

Other spiders, such as net-casting spiders, have very enlarged rear eyes that almost look like search-lights. These also give them an advantage for night hunting – this gives them a wider field of view and are great in low light conditions.

Jumping spiders have been thought to have the best vision out of all spiders. They are more active during the day, so their eyes work a bit differently. Their vision is excellent, allowing them to differentiate prey from mates and enemies. Their amazing vision also allows them to pounce on their prey very accurately, from distances over 20 times their body length. Jumping spiders actually have three different kinds of eyes: They have side eyes that sense movement of distant prey through a blurry wide-angle image. Once movement is picked up, the spider will focus on the moving prey with its large middle front eyes which provide a clear color image. These eyes can track moving prey and lock onto it. Then, when the prey is within a closer range, the side front eyes judge how far the spider would have to leap to get the prey.

I never knew there were so many different types of spider eyes! This was fascinating 🙂