Spiders: The eight-eyed, eight-legged critters. What are they? Cyclopes? Insects?

No. Spiders are neither insects nor mythical giants like Cyclopes — they are arachnids, related to ticks, scorpions, and mites. All arachnids, including spiders, have eight legs.

Here are a few more interesting facts about spiders:

1. Most spiders have eight eyes, although some have six, four, or even two. There are also species — like cave-dwelling spiders — that have no eyes at all because they live in perpetual darkness. In eight-eyed spiders, two large front eyes handle most of the seeing, while three pairs of side eyes detect movement.

Compound eyes of a spider. Source: animalcorner.org

2. Most spiders have poor eyesight, capable only of detecting movement and changes in light. Net-casting spiders, however, have excellent night vision and a wide field of view thanks to their two huge front eyes. Jumping spiders have some of the best eyesight among all spiders — they can see colors and even detect both UVA and UVB light.

3. The vast majority of spiders — there are a mind-blowing 30,000 or more species on our planet! — are not harmful to humans. They play a very important role in ecosystems by devouring pests that would otherwise destroy crops. Just imagine: tons upon tons of crops saved thanks to spiders!

4. Some spiders are tiny. For example, Patu digua of Colombia has a body length of just 0.014” (0.37 mm). Meanwhile, the Goliath birdeater — a type of tarantula — can have a leg span of up to 11” (28 cm) and weigh as much as 6 oz (170 g)!

All spiders have 8 legs, as can be seen in this attractive Mexican Redknee tarantula. Source: phys.org

5. Spiders exhibit a dazzling variety of colors and patterns, helping them blend into their surroundings — a brilliant strategy for both defense and offense.

The beautiful Peacock Jumping spider. Source: theguardian.com

6. Many spiders, such as wolf spiders, do not build webs but instead actively hunt their prey.

7. Incredibly, the silk in a spider’s web is about five times stronger than a steel strand of the same thickness. Scientists say that a web made of strands as thick as a pencil could stop an airplane. Chew on that for a moment!

8. Spider silk is actually a liquid. When a spider releases it to build a web, it hardens upon contact. The moist silk allows the spider to manipulate it with remarkable precision — yet another example of nature’s ingenuity.

9. And surprise, surprise — spider blood is blue! Why? In humans, oxygen binds to a molecule containing iron, giving our blood its red color. But in spiders, oxygen binds to a molecule containing copper, which turns their blood blue. Fascinating, isn’t it?

10. Female spiders have voracious appetites. In many species, the female will eat her mate before, during, or after mating. Beware!

11. If you observe a dead spider closely, you’ll notice its legs are always curled inward — without exception. Why? Spider muscles can only pull their legs inward; they cannot extend them outward. To extend, spiders rely on hydraulic pressure created by a watery fluid in their bodies, called hemolymph. This same mechanism also enables some spiders to jump. When a spider dies and the fluid is no longer circulating, the legs curl inward. Mystery solved!

12. Finally, spiders are found on every continent — except Antarctica.

Did You Know?

• Spiders have been living on Earth for a long time — about 400 million years!

• Even though a spider’s eyesight is rather poor, it is extremely sensitive to its surroundings. Thousands of small hairs on its body and legs contain highly sensitive receptors that can detect the slightest vibrations, from 100–10,000 Hz. Virtually nothing escapes them.

• Wolf spiders, known for their hunting prowess and diverse habitats, are among the most common spider types worldwide, with over 2,300 species.

  
  

  

  A wolf spider does not need a web to attract its prey. Source: arrownj.com

• Jumping spiders make up about 13% of all described spiders. Their ability to jump, excellent eyesight, and diverse appearances contribute to their widespread presence.

• Orb-weaver spiders, famous for their intricate, wheel-shaped webs, are common globally.

• House spiders are frequently found in human dwellings around the world.

• Black widow spiders are found globally. Female black widows are known for their venomous bite and distinctive red hourglass marking.

• Brown recluse spiders are widespread in certain regions, such as the Midwestern United States, and are known for their reclusive behavior and potentially serious bite.

• Tarantulas are large, hairy spiders found worldwide and are easily recognized.

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