How Good is a Spider’s Eyesight?
Spiders have eyes that are highly developed, with a wide variety of vision. They use their vision to detect motion, and their vision has evolved to cover a wide range of light. Their ability to see colors varies with species. Some spiders have crude form of color vision, and some have more advanced color vision.
Most spiders have eight eyes. Some spiders have six or fewer. The number of eyes in a species is often determined by how well a spider’s eyesight is suited to its needs. Hunting spiders have better eyesight than web-building spiders. Baby jumping spiders have eyes that are still developing. These still-growing eyes can help us understand more about the evolution of eyesight in animals.
Jumping spiders’ eyes are among the sharpest in the animal kingdom. This gives them the ability to see a wide variety of colors, including red, yellow, blue, and orange. And their ability to see red evolved to avoid toxic prey.
Spiders are active during the day, but they can also hunt at night. Because they can detect changes in the intensity of light and dark, they can trigger nocturnal web building. Several species of jumpers have a filter between green photoreceptors, which allows them to detect red light.
Whether a spider has a high or low resolution vision depends on the position of its eyes. Spiders have either an indirect eye or a direct eye, which can function at low light intensities.