Eye see you!

What am I looking at?

This is a Woodland giant wolf spider (Tigrosa aspersa), in her burrow. Like many other night-hunting animals, wolf spiders show reflective “eyeshine” (1), much like the eyes of our pet cats and dogs. You can also see the spider’s front legs (2) and the tops of its fangs (chelicera - 3).

Biology in the Background

Although this wolf spider is a burrowing species, all wolf spiders are active hunters, venturing into the open to search for prey. Wolf spiders are reclusive and far more numerous than one might suspect. They live in temperate climates all over the world. If you do go out at night with a flashlight, you will very likely see the glinting eyes of one or more of these spiders.

But what causes eyeshine? Not all light that enters an eye is absorbed by the retina. Nocturnal animals often have a reflective layer called the tapetum lucidum behind their retinas, doubling the chance that photons will be absorbed by the photoreceptor cells, and increasing the animal’s ability to see at night.

For spiders, wolf spiders have good eyesight, but they also have a keen sense for touch and can detect even the tiniest vibrations through sensory bristles on their legs, so they are both visual and tactile hunters.  

Wolf spiders can grow relatively large for a spider with leg spans reaching up to almost 12 centimeters, or a little less than 5 inches.  

Technique

This image was created using macrophotography.