Spiders Cannot Physically Chew Their Food

When a spider ensnares a fly in its web, the ensuing bite delivers more than just paralyzing venom. It’s the start of a bizarre culinary process known as extra-oral digestion. Lacking the teeth and jaw structure necessary for grinding solid matter, spiders have evolved to digest their meals before they even eat them. The venom they inject is often a potent cocktail of neurotoxins and digestive enzymes that begin to break down the prey’s soft tissues from the inside out, essentially turning its organs into a nutrient-rich slurry.

This unique feeding strategy is a masterclass in adaptation. The spider's mouthparts, particularly its chelicerae (fangs) and a powerful sucking stomach, are perfectly designed for this liquid diet. After the enzymes have done their work, the spider uses its pharynx to pump the liquefied remains into its digestive system, leaving behind a hollow exoskeleton. For larger prey, some spiders, like tarantulas, will even regurgitate digestive fluids onto the victim to help break it down externally.

The familiar sight of a silk-wrapped insect is a practical necessity for this slow-acting method. The silk casing not only secures the struggling prey but also acts as a tidy container, preventing the valuable "soup" from leaking away as the digestion process unfolds. This can take several hours, so the silk ensures the spider’s hard-won meal doesn’t dry out or get stolen by another predator before it's ready to be consumed.