How Do Tarantulas Eat?
Most tarantula keepers are familiar with the basic feeding process. You drop in a cricket, the tarantula pounces, the prey disappears under a pile of legs, and a few hours later, there is nothing left but a little wad of insect parts in the corner of the enclosure.
What is actually happening is much stranger than you may realize because tarantulas do not eat the way mammals, reptiles, and most other animals do. They do not take bites, chew their food into pieces, swallow those pieces, and let the stomach handle the rest. Their entire feeding system is built around subduing prey, breaking it open, digesting much of it outside the body, filtering out the parts they cannot use, and drinking the liquefied nutrients.
Tarantulas Are Liquid Feeders
The most important thing to understand is that tarantulas cannot swallow solid chunks of food the way a bearded dragon or golden retriever can. Their mouth opening is small, and their internal feeding system is designed for heavily liquefied food. So when a tarantula catches a cricket or roach, the goal is not to swallow the animal whole like a snake. The goal is to extract the usable nutrients from inside that prey and leave the hard, indigestible parts behind.
This is why tarantulas spend so much time working their prey with their fangs. They are not just sitting there holding it because they got tired or forgot what they were doing. They are literally processing the meal. Larger prey or prey with thick exoskeletons can take longer to break down, so a tarantula feeding for a long time is usually not a problem. That’s typical of the feeding process, and like most things concerning tarantulas, it requires patience.
The Strike and the Role of Venom
When a tarantula grabs prey, they use their chelicerae, which are the powerful mouthpart structures that hold the fangs. Those fangs puncture the prey and deliver venom. Tarantula venom is not just one simple chemical. Spider venom is a complex mixture of chemical compounds, many of which affect the prey’s nervous system to immobilize them quickly. The exact mix can vary from species to species, and even within the same species, depending on age, sex, diet, habitat, and other factors. So when we talk about tarantula venom, we are really talking about thousands of different evolved recipes, each shaped by the animal’s lifestyle and evolutionary history.
Some venom components may also help begin the breakdown process, but venom is not the entire feeding system. A tarantula does not just bite a cricket, wait for venom to magically melt everything, and then sip it up like a milkshake. The venom helps immobilize the prey and can contribute to early digestion. However, the real feeding process is much more mechanical and much more involved.
The Part That Looks Like Chewing
Tarantulas have fangs, but fangs are not teeth in the way most people think of teeth. They are not chewing a cricket like a cat chewing kibble. The fangs puncture, hold, and help manipulate the prey. The chelicerae and surrounding mouthparts can also crush, tear, and work the prey against hardened surfaces and small tooth-like structures.
If you have ever watched a tarantula feed, you have probably seen them slowly rotate the prey item, reposition it, and almost knead it under their body. That movement is part of the process. They are breaking open the prey’s exoskeleton, exposing the soft tissues inside, spreading digestive fluids, and creating access points where those fluids can do their job. It may look like they are “chewing,” even though they are not chewing in the same way we do. It is eating, but it is also food preparation.
Extra-Oral Digestion
The main process tarantulas use is called extra-oral digestion. That sounds like a phrase designed specifically to make normal people stop reading, but it just means digestion happens outside the mouth before the food is swallowed.
Instead of swallowing solid food and letting the stomach handle everything internally, the tarantula releases digestive fluids onto or into the prey. Those fluids contain enzymes that break down proteins, fats, and other tissues. Kind of like a biological meat tenderizer. The digestive fluid breaks down the soft internal parts of the prey until they become liquid enough for the tarantula to drink.
This is not unique to tarantulas, either. Many spiders and other predatory arthropods use some version of extra-oral digestion. It also explains why tarantulas leave behind a bolus. They are not eating the entire cricket. They are extracting what they can use and leaving behind what they cannot.
The Sucking Stomach
Once the prey has been liquefied enough, the tarantula pulls that liquid into their body using a muscular pump called the sucking stomach. I know that sounds fake, but that is basically what it does and what they call it.
The sucking stomach expands and contracts, creating suction that moves liquefied food through the mouth and into the digestive tract, not unlike using a turkey baster. This is one of the reasons tarantulas are so specialized for liquid feeding. Their system is not built for big chunks of solid food. It is built to pull in nutrient-rich liquid after the prey has already been broken down externally. Then, once that liquid food enters the body, digestion continues internally. The nutrients are broken down further and absorbed. Like other spiders, tarantulas have digestive branches that extend through their body to help distribute nutrients where they are needed. That liquid meal becomes fuel for movement, webbing, growth, molting, reproduction, and all the other things that keep your tarantula alive. Think of this part like how kids eat squeezable snack packs.
Filtering Out the Junk
Because tarantulas are liquefying prey from the outside, filtering becomes very important. The prey still has hard parts that the tarantula cannot use. Cricket legs, wings, pieces of exoskeleton, spines, and other solid fragments need to be kept out of the digestive tract as much as possible. The mouthparts help strain and filter the liquid food before it is taken in.
This mechanism accounts for why the remains of leftover prey often look like a compact little ball of crushed insect parts. That leftover mass is called a bolus. It is basically the dry, indigestible material left over after the tarantula has extracted the useful parts of the meal.
In a simple enclosure, you can remove boluses whenever you find them. In a humid or bioactive enclosure, it becomes even more important to keep an eye on them. Leftover prey remains can mold, attract mites, or create little pockets of decay if they sit too long. Springtails and isopods can help clean up small organic material in a bioactive setup, but they are not a replacement for basic spot cleaning.
Why Prey Size Matters
Understanding how tarantulas eat also explains why prey size matters. A tarantula does not need to overpower something enormous to get a good meal. In fact, oversized prey can create unnecessary risk, especially for spiderlings or freshly molted tarantulas. Appropriately sized prey is easier to subdue, easier to manipulate, and easier to process. A tarantula feeding on a reasonable prey item can focus on eating, while a tarantula dealing with a feeder that is too large may spend more energy defending itself or just abandoning the meal entirely.
Spiderlings, or very young tarantulas, will often scavenge, which is why pre-killed prey or chopped feeder pieces can work so well. You don’t always need to drop a live cricket into a tiny sling enclosure. If the prey is fresh, appropriately sized, and placed near the burrow or webbing, many slings will feed on it once they feel secure.
For juveniles and adults, live prey is usually accepted readily, but uneaten prey should still be removed within 24 hours. A cricket that was supposed to be dinner last night can become a problem by the morning if your tarantula goes into premolt, molts unexpectedly, or simply decides they are not interested. Crickets, roaches, mealworms, and even isopods have been known to chew on a molting tarantula, which can cause severe harm or even kill a defenseless tarantula.
Hydration Matters More Than People Think
Because tarantulas rely on liquefied food, hydration really matters. A dehydrated tarantula may have a weaker feeding response, may struggle more with digestion, and may be at greater risk during molting. That does not mean every tarantula enclosure should be wet. It means the animal should have access to the moisture level appropriate for the species.
For most tarantulas, a water dish should always be available once they are large enough. For spiderlings, moisture can be provided with a very small water dish if there is space, or by carefully moistening part of the substrate. The goal is to give the tarantula access to moisture without turning the enclosure into a stagnant, moldy mess.
This is where substrate makes a difference. A moisture-retentive substrate like Terra Aranea helps create stable moisture gradients rather than sudden swings from bone-dry to swampy. Add cork bark, leaf litter, sphagnum moss where appropriate, and proper ventilation, and the enclosure becomes more than a container with dirt in it. It becomes a system with choices.
Gutloading Feeders Actually Matters
Since tarantulas are drinking the liquefied contents of their prey, the quality of that prey matters. A cricket that has been sitting in a cup with nothing but dry cardboard and dead crickets is not the same as a cricket that has been kept and fed properly.
Gutloading is very simple but very necessary. Feed your crickets, roaches, or other feeder insects nutritious foods for at least 24 hours before offering them to your tarantula. Fresh vegetables, leafy greens, squash, carrots, fruit, and quality feeder diets all help improve the nutritional value of the prey. Their feeders should be treated like part of the husbandry chain. Healthy feeders make better meals. Since your tarantula is extracting nutrients from the inside of that prey, what the prey has eaten matters a lot!
Why Tarantulas Refuse Food
Once you understand how tarantulas eat, food refusal starts making more sense. A tarantula may refuse food either because they are full or because they are in premolt. They may refuse food because temperatures have dropped, the enclosure is too dry, the prey is too large, or they are just stressed from a recent rehousing. Mature males often stop eating because their biology has shifted. At that point, their priority is finding a female, not sitting around getting fat on roaches.
Food refusal is not automatically a crisis.
Look at the whole animal. Look at their abdomen. Look at the enclosure conditions. Look for signs of premolt. Then decide whether anything actually needs to change. A lot of the time, the correct response is patience.
Trying to force the issue usually creates more problems than it solves. Don't shove prey in your tarantula’s face, and don’t leave crickets roaming around their enclosure for days. Don’t dig your spider out of their sealed burrow because they skipped a meal. Just remove the prey, check your husbandry, be patient, and try again later.
Final Thoughts
Feeding is one of the most exciting parts of keeping tarantulas, but it becomes even more interesting when you understand what is actually happening. They are not just biting something and swallowing it. They use venom, muscle, chelicerae, digestive fluids, filtering structures, and a biological pump to turn another animal into a drinkable meal.
That is what makes even a simple feeding response so impressive. Offering a cricket gives you a window into a completely different way of being alive. These animals are not tiny monsters mindlessly crushing bugs. They are specialized predators with a feeding system that has been working for a very, very long time.
And the better we understand that process, the better we can care for them. Appropriate prey size, healthy feeders, proper hydration, stable substrate, and patience all make more sense when you understand how a tarantula actually eats.
That little bolus left behind in the corner is not just their leftovers. It is proof that the whole system worked.
- Josh Halter
