Spiders are among the most primitive of all terrestrial predators. Not long after insects first invaded the land the primitive ancestors of modern spiders followed to gorge themselves on the newly invaded soil. Today spiders still hunt their insect prey as they did millions of year ago. The technique used to capture their prey varies widely and is even specific to a particular species. The classic example is spider’s webs. A silken web of sticky strings that capture prey in a tangled coffin. Although all spiders have the capacity to make silk not all spiders build webs. Some spiders are active hunters, the wolf spiders, jumping spiders, and crab spider are all predators on the foot. They stealthy stalk their prey and attack with vicious speed and agility. They are true predators in every sense of the word.
Because spiders have an extremely low metabolism they have the uncanny ability to wait. They can go day or even weeks without eating, simply waiting for their prey to make a fatal error. Crab spiders are among those species who do not build webs but rather wait for their prey to come to them.
I found this large, perfectly white, crab spider perched on a large daisy in one of my backyard gardens. It sat motionless waiting for an unsuspecting pollinator to land for a quick meal. Crab spiders get their name from the way they hold their legs out stretched, much like a crab. Unlike a crab these spiders do not walk sideways, their legs are out stretched like a foot trap waiting to spring.
If an unsuspecting pollinator does land on this particularly deadly daisy the spider’s trap will be sprung. In the blink of an eye the spider’s forelimbs will spring forward and snare its prey delivering a fatal bite from the spider’s fangs. If there ever were an arachnid equivalent to a military sniper this it.
Even the spider’s eyes are adapted for ideal vision and ranging. It’s large binocular vision allows it to perceive motion and distance with deadly accuracy. Even on this minute scale the adaptation for binocular vision in predators is very apparent (large predators typically have their eyes in the front to allow for accurate interpretation of motion and distance, think lions, eagles, wolves, and even people!).
Even the most serene of places has a never ending struggle between life and death occurring just out of sight. The battle is not invisible but is only view by those with a curious eye. Next time you see a spider, stop and ask yourself what it is really up to. Is just aimlessly walking around or is it out on the hunt!