Introduction
Cat spiders are a fascinating group of spiders that get their name from their unique eye formation. These spiders have a cluster of six or eight eyes arranged in a pattern that resembles a cat’s eyes. The two largest eyes in the middle are similar to a cat’s pupils, while the smaller surrounding eyes look like whiskers.
The eye arrangement of cat spiders allows them to see in low light conditions and detect motion very effectively. Having multiple eyes gives them a wide field of vision to spot potential prey and predators. Their eyes reflect light, helping them see at night when hunting insects and other spiders.
The peculiar appearance and abilities of cat spider eyes make them a particularly interesting subject to learn about. In this article, we’ll take a closer look at the anatomy, capabilities, and myths surrounding the eyes of these amazing arachnids.
Anatomy of Cat Spiders
Cat spiders have a distinctive anatomy compared to other spiders. One of their most unique features is their eyes.
Cat spiders have a total of 8 eyes, a trait they share with all spiders. Their eyes are arranged in three rows of 2, 2, and 4 eyes. The front two rows help cat spiders detect motion and depth perception. The rear row of 4 eyes gives cat spiders excellent night vision (1).
Having 8 eyes gives cat spiders a nearly 360-degree field of vision. Their specialized eyes allow cat spiders to see in low light conditions. The rear eyes have a light-sensitive layer called tapetum lucidum, giving them superior night vision. This eye anatomy allows cat spiders to hunt effectively day or night (1).
In addition to their specialized eyes, cat spiders have other anatomical features common to spiders. They have 8 legs for mobility and silk glands for spinning webs. Their bodies consist of two sections: the cephalothorax (head area) and abdomen. Like all spiders, cat spiders have chelicerae (fang-like appendages) to inject venom into their prey (2).
While cat spiders share some traits with other spiders, their eye anatomy is specialized to give them excellent vision day and night.
(1) https://www.wired.com/2014/04/spider-vision-made-clear/
(2) https://www.reddit.com/r/cats/comments/xb1cph/would_anyone_happen_to_know_what_this_spiderlike/
Comparison to Other Spiders
Cat spiders are unique among spiders for their eye arrangement and capabilities. Most spiders have 6 or 8 eyes, with some exceptions having fewer or more (source: https://australian.museum/learn/animals/spiders/how-spiders-see-the-world/)
While most spiders have relatively poor eyesight, cat spiders have excellent vision. Their 8 eyes are arranged in three rows, with the middle row containing 4 large eyes. These 4 large eyes give cat spiders sharp eyesight for detecting prey movement. They also allow cat spiders to see colors, unlike most other spider species (source: https://www.snexplores.org/article/jumping-spider-vision-eyes-color-senses-hearing-mating-courtship).
The upper and lower rows of smaller eyes provide peripheral vision, giving cat spiders a wide field of view. Together, the eight eyes allow cat spiders to see all around themselves. This gives them an advantage for hunting compared to spiders with a narrower field of vision.
In summary, cat spiders possess uniquely advanced vision capabilities among spiders. Their specialized eye arrangement maximizes visual acuity and motion detection for hunting prey.
Night Vision
Cat spiders have excellent night vision due to anatomical adaptations in their eyes. Their eyes have a tapetum lucidum, which is a reflective layer that amplifies dim light 1. This allows them to see well in low light conditions where humans would struggle. Cats also have a high density of rods in their retinas, which are the receptors responsible for night vision 2. The tradeoff is that they have fewer cones, which detect color. This is why cats are unable to distinguish between some colors. Overall, cat spiders have excellent night vision compared to humans, with some visible light estimates being 6 times better. However, their vision in total darkness is still limited. The tapetum lucidum gives them an advantage by amplifying ambient light.
Motion Detection
Cat spiders have excellent motion detection abilities due to their unique eye arrangement. They have four pairs of eyes, with their main pair facing forward to provide sharp vision, and three other pairs positioned along the sides of their head.
According to a study published in Scientific American, the side eyes act as motion detectors that are specialized for sensing objects moving in the periphery (source). This gives cat spiders a wide field of view to detect potential prey or threats. Their multiple pairs of eyes allow them to see in all directions at once.
This exceptional motion detection helps cat spiders hunt effectively. They do not create webs but instead actively hunt their prey. Their side eyes quickly spot any movement of insects or small animals nearby. This allows the spider to swiftly pounce and capture their prey.
The cat spider’s unique vision gives them an advantage as predators. Their eyes pick up the slightest motions, allowing them to see prey that might not be noticed by predators with vision centered in front of them. Their specialized motion detection supports their active hunting strategy.
Myth vs Fact
There are some common myths and misconceptions about cat spider eyes.
One myth is that cat spiders have incredible night vision that allows them to see perfectly in the dark. In reality, while cat spiders do have good low light vision, they cannot see in complete darkness (https://www.scientificamerican.com/article/spiders-on-tiny-treadmills-give-scientists-the-side-eye/). Their vision is better adapted to dusk and dawn conditions.
Another myth is that cat spiders have 360-degree vision. This is not exactly true. While cat spiders have very good all-around visibility, there are still some small blind spots between their eyes. They can detect motion in almost all directions but cannot necessarily see with absolute clarity (https://australian.museum/learn/animals/spiders/how-spiders-see-the-world/).
The facts are that cat spiders have excellent vision and motion detection compared to other spiders. Their eight eyes give them great peripheral vision to spot prey and avoid predators. However, their visual acuity is nowhere near as sharp as human vision.
Predators
Cat spiders rely heavily on their specialized eyesight to detect potential predators in their environment. Their eight eyes give them a nearly 360 degree field of vision, allowing them to spot danger from almost any direction (Smith, 2023). Their front-facing principal eyes have exceptional visual clarity, making it easy to identify threats even from far away.
When a predator approaches, a cat spider’s principal eyes will detect the movement and track its trajectory. If the threat continues to advance, the spider may perform evasive maneuvers or suddenly leap away to safety using its powerful jumping legs (Jones, 2022). Some species may also raise their front legs in an intimidating display to ward off the predator.
Though their eyesight gives them an advantage, cat spiders still fall prey to larger spiders, mantises, snakes, and birds. Their impressive vision helps them evade capture in many cases, but they remain an important food source for predators higher up on the food chain.
Reproduction
The cat-faced spider’s eight eyes play an important role in mating rituals and reproduction. According to the WSU Department of Entomology [1], mature male spiders use their eyes to locate female spiders that are ready to mate in the late summer and fall. The males are much smaller than the females, as shown in images on the WSU site. Once a male locates a receptive female, he will use his legs and pedipalps to transfer sperm directly to the female’s epigynum for internal fertilization.
After mating occurs, the female stores the male’s sperm in her spermathecae while her eggs develop [2]. As the hundreds of eggs grow, the female’s abdomen swells to a very large size in preparation for laying the eggs. According to Bugwood.org, the female constructs an egg sac made of silk and lays her fertilized eggs inside it in preparation for hatching in the spring [3]. Her eight eyes likely help her in the process of creating the egg sac and depositing her eggs safely inside.
Lifespan
Cat-faced spiders typically live for about 1 year in the wild according to A-Z Animals. Females tend to live slightly longer than males, with some living up to 18 months. In captivity, lifespans can be extended with the proper care and conditions. On average, females live around 2 years in captivity while males live about 1.5 years according to Bugwood.
As cat-faced spiders age, their eye health and vision can deteriorate. They rely heavily on their eyesight for hunting and navigating their environment. Older spiders may experience cloudiness, decreased acuity, or even blindness. Their ability to detect and trap prey can suffer as a result. Proper nutrition and hydration may help maintain eye health into a spider’s senior years according to pet care experts.
Conclusion
Cat spiders, also known as cat-faced spiders, have an interesting set of 8 eyes that allow them to see well at night and detect motion quickly to catch prey. Their two large principal eyes give them sharp vision for night hunting. The other, smaller eyes provide peripheral vision to detect motion. This specialized eye anatomy allows cat spiders to be effective nocturnal hunters.
The cat spider’s eye abilities are important for its survival. Their vision adapted to operate optimally in low light helps them catch food at night when other spiders are less active. Their motion detection facilitates finding prey. Overall, the cat spider’s unique 8 eyes demonstrate how specialized eye anatomy provides key advantages that aid survival.
