What Can Spiders Eat?
Spiders are opportunistic and versatile predators capable of consuming a wide variety of prey, depending on their species, size, hunting method, and habitat. Here’s an overview of what spiders are capable of eating:
Insects
This is the most common dietary component for most spiders. They consume a wide range of insects, including:
Some spiders prefer specific prey types, while others are generalists.
Other Arthropods
Spiders also eat a variety of non-insect arthropods, such as:
Other spiders (cannibalism is common, especially among females and during mating encounters)
Centipedes and millipedes
Isopods (e.g., pillbugs or sowbugs)
Larger Prey (for Bigger Species)
Larger spider species, such as tarantulas and huntsman spiders, are capable of overpowering and consuming:
Small reptiles (e.g., lizards, geckos)
Small amphibians (e.g., frogs, toads)
Small mammals (e.g., baby mice)
Small birds (rare, but documented in large spiders like the Goliath birdeater)
These events are uncommon and generally restricted to large, powerful species capable of subduing and digesting such prey.
Aquatic and Semi-Aquatic Prey
Some spiders, like the fishing spider (Dolomedes), are adapted to living near water and can catch:
Small fish
Tadpoles
Aquatic insects (e.g., water striders, mosquito larvae)
They can walk on water and dive to catch prey, using surface tension and their hydrophobic leg hairs to stay afloat.
Scavenging and Unusual Behavior
While spiders predominantly consume live prey, under certain conditions they may:
Scavenge dead insects (especially in captivity)
Consume nectar or pollen (rare but observed in some jumping spiders)
Feed on plant matter (very rare and not a typical behavior for most species)
How Spiders Eat
Spiders cannot chew solid food. Instead, they inject digestive enzymes into or onto their prey through their fangs (chelicerae), which liquefies the tissues. They then suck up the resulting liquid. This process is called extraoral digestion, and it allows spiders to extract nutrients without ingesting hard exoskeletons or inedible parts.
Spiders are highly effective and adaptable predators, with diets primarily consisting of insects and other arthropods. Some larger species can consume vertebrates, and certain specialized spiders have even adapted to aquatic or nectar-based food sources.
What Do Spiders Eat?
Spiders generally prefer to eat live prey that they can subdue, immobilize, and digest with their specialized venom and digestive enzymes. Their preferences vary by species, but there are common patterns based on evolutionary adaptations, hunting strategies, and ecological niches. Here's what spiders prefer to eat and why:
Small, Soft-Bodied Insects (Primary Preference)
Spiders overwhelmingly prefer soft-bodied, fast-moving insects, which are easier to immobilize, digest, and consume. These include:
Flies – Common prey for many web-building and hunting spiders; abundant and easy to catch.
Mosquitoes – Readily trapped by webs, particularly orb-weavers.
Moths and butterflies – Frequently caught in webs, especially near lights at night.
Gnats and midges – Ideal for smaller spiders due to their size and soft bodies.
Ants – Some spiders specialize in hunting ants, although many avoid them due to their aggressive nature and chemical defenses.
Spiders favor prey that is high in protein and easy to digest, with minimal risk during the capture process.
Web-Spinners vs. Active Hunters
Preferences also depend on the spider’s method of hunting:
Web-Building Spiders
These spiders prefer:
Flying insects that blunder into webs (e.g., flies, mosquitoes, moths)
Prey that struggles in the web, triggering capture behavior
Common examples: Orb-weavers, funnel web spiders, cellar spiders
Active Hunting Spiders
These spiders do not build webs to catch prey but stalk or ambush it, favoring:
Examples: Jumping spiders (Salticidae), wolf spiders, crab spiders
Jumping spiders, in particular, show high visual acuity and may prefer prey that moves in a visually stimulating way.
Cannibalism and Mating Preferences
Many spiders show sexual cannibalism (especially females), and cannibalism is not uncommon in crowded or food-scarce environments. However, this is not a “preferred” food source—it's typically driven by:
Hunger
Stress
Competition
Nutritional Value Drives Preference
Spiders may exhibit food preferences based on the nutritional content of their prey. They often favor:
High-protein prey for growth and reproduction
Prey rich in lipids (fat) during molting or egg production
Some spiders will reject prey with low nutritional value or that is overly difficult to subdue relative to the benefit.
Size Matters
Spiders typically prefer prey that is:
Smaller than or equal to their own body size
Not too heavily armored, as hard exoskeletons are difficult to penetrate or digest
They may avoid prey that can injure them, such as wasps, large beetles, or certain ants.
Specialized Preferences
Certain spider species exhibit highly specialized diets:
Ant-mimicking spiders (e.g., Myrmarachne) may exclusively hunt ants.
Spitting spiders specialize in pinning down prey with silk and venom.
Bolas spiders lure moths using pheromones and selectively prey on male moths of specific species.
Portia spiders (jumping spiders) exhibit complex hunting behavior and often prefer other spiders.