Do Frogs Eat Spiders? (What About Highly Venomous Ones?)

Frogs and toads are generalist carnivores that feast on worms and a wide variety of bugs. They are even known to eat stinging insects like wasps and bees, and some frogs even eat snakes! But do frogs eat spiders?

In general, frogs eat spiders that are small enough to fit into their mouths. They are opportunistic predators that will eat almost any prey they can catch and fit into their mouths, and this includes spiders. When a frog eats a spider, it quickly immobilizes and swallows it before it can bite 

That being said, it is important to note that spiders will not be the first choice of meal for most frogs. They will eat spiders when the opportunity presents itself, but will not purposely seek out spiders to eat.

Frogs Eat Smaller Spiders

Frogs are opportunistic predators with very diverse diets. Smaller frogs mostly eat ants, small worms, and a wide variety of bugs, but large frogs such as bullfrogs will also eat large snails, smaller amphibians, mice, small reptiles, and even birds.

Almost prey is slow enough to catch and small enough to fit into the mouth, it is on the menu.

A green tree frog eating a spider.
A tree frog eating a spider. Photo by: Bubba73 , CC BY-SA 3.0, via Wikimedia Commons.

If a small enough spider passes in front of a hungry frog, the frog will try to eat it.

Some Frogs Eat Spiders More Frequently Than Others

Frogs have diets that depend on the food sources available in their environments. For this reason, highly terrestrial frogs will eat spiders more frequently than frogs that spend most of their time in the water.

Aquatic frogs will have a diet that is based on the food available in the aquatic habitats, which will include fish, fish eggs, and aquatic insects.

However, if the opportunity presents itself, (for example, a spider falls into a pond where a frog is), even aquatic frogs will eat spiders.

How Do Frogs Eat Spiders

Frogs catch and eat spiders the same way they eat bugs. They have sticky tongues that allow them to catch any moving prey that comes into range quickly.

Once a frog spots a spider, it launches its tongue to catch the prey. After catching the prey, the tongue wraps around it and coats it with sticky saliva. The frog will then yank its tongue back with a force equal to twelve times greater than the force of gravity.

Once the spider is in the mouth, the frog will swallow it whole (although frogs have teeth, they do not use them to chew, but rather to maintain a grip on their prey as they swallow it whole).

A frog can shoot out its tongue, capture a spider and pull it back into its mouth within 07 seconds; which is five times faster than the human eye can blink. This speed makes it effective at catching even fast-flying insects such as flies.

Do Frogs Get Bitten When They Eat Spiders?

When a frog eats a spider, it typically swallows the spider before it can bite

Once the spider is captured, the frog’s sticky saliva covers it and immobilizes it quickly before it’s able to bite; the spider is then quickly swallowed.

Still, sometimes frogs get bitten when they try to eat spiders.

Frogs and toads are not immune to spider venom, so if a frog gets bitten, it will feel pain. A single bite from most spiders is usually not enough to phase most frogs or stop them from eating spiders in the future.

However, if a frog is bitten several times, it may remember the experience, and learn to avoid eating spiders a for some time.

Still, after a while, it may forget about the experience and will catch and eat spiders again

Do Frogs Eat Highly Venomous Spiders?

Most spiders are only mildly venomous, so the bites from these spiders do not cause any serious harm to frogs.

However, some spiders such as the Brown Recluse Spider, and widow spiders have very potent venom.

If a frog were to eat one of these spiders, and the spider bit the frog on the way down – it is highly likely the spider could seriously harm, or even kill the frog.

Black widow spiders are highly venomous
Black widow spider. Photo by: glezah, via, inaturalist.

Still, once the possible bite is taken out of the equation, frogs can eat even highly venomous spiders without any problems.

Venom is only harmful when injected, so as long as the spider does not bite the frog, the venom is not harmful – and will be digested when it comes in contact with the frog’s stomach acids.

Large Spiders Sometimes Eat Small Frogs

While frogs can eat spiders, some large species of spiders such as Huntsman spiders, Fishing spiders, Wandering spiders, and Wolf spiders also very frequently prey on small frogs.

A fishing spider eating a lesser tree frog jpg
A giant fishing spider eating a lesser tree frog. Photo by: Bernard DUPONT via, flickr.

These spiders use a wide variety of hunting techniques to catch frogs.

For example, wolf spiders capture frogs by popping out of their underground burrows and grabbing them as they walk by. The spider injects the frog with venom that liquefies its internal organs, which the frog then sucks out.

Fishing spiders, on the other hand, hunt frogs by resting on the water’s surface with their hind legs anchored on a leaf or rock. When the spider detects the vibrations of a passing frog, it pounces and grabs the frog.

It then injects the frog with venom that liquefies its insides which the frog then sucks out.

Can Captive Frogs Be Fed Spiders?

Most hobbyists don’t feed snakes to their frogs for two main reasons.

One, spiders can bite and even seriously injure a frog during feeding.

Two, it is somewhat impractical for hobbyists to feed spiders to their frogs. It’s usually cheaper, faster, and easier to feed insects and worms to amphibians.

Also, since frogs generally eat live prey, the “feeder spiders” would have to be kept alive for long periods before they are fed to the frog.

It makes little sense to feed spiders to captive frogs because there are cheaper and easier alternative prey items out there.

Still, captive frogs will eat spiders when they are offered. That being said, it is not a good idea to offer spiders to your frog as they could bite, and even seriously harm the frog. It is much better to only feed things that can not bite, sting, or harm the frog in any way.

Here is a list of things you can feed a captive frog:

Other things frogs can be fed in captivity

  • Worms (earthworms, whiteworms, blackworms, etc)
  • Mealworms, Waxworms, Phoenix worms, Silkworms, superworms
  • Grubs
  • Crickets 
  • Dubia roaches
  • Wingless fruit flies
  • Feeder Fish 
  • Pinkie mice (for large frogs such as bullfrogs)

The most appropriate food will depend on the size and species of the frog. For example, some tree frogs won’t eat mealworms, but will readily accept crickets and wingless fruit flies.

Large frogs, such as bullfrogs enjoy the occasional “pinkie” in their diet. A “pinkie” is a tiny, baby mouse. You can find them in pet stores either alive or frozen although it can be difficult to get frogs to eat the dead/frozen ones.

A varied diet is recommended, so be sure to change up the food items offered to the frog every few feedings.

NOTE: Frogs only eat live prey and will avoid dead bugs and other dead prey items. For this reason, it’s recommended to only offer live prey items to a captive frog.

What Other Predators Eat Spiders?

Frogs and toads are not the only animals that prey on spiders. Spiders are also regularly eaten by lizards, chameleons, birds, monkeys, fish, centipedes, scorpions, and some insects such as tarantula hawks, and spider wasps.

In addition, spiders frequently eat other spiders. For example, some female black widow spiders sometimes cannibalize male spiders after mating with them.

Frequently Asked Questions (FAQS)

How do frogs eat spiders without getting bit? Frogs eat spiders without getting bit by immobilizing them they can bite. Once a frog spots a spider, it lashes out its sticky tongue before the spider has time to notice. The tongue then wraps around the spider and coats it with sticky saliva – which immobilizes it. The spider is then quickly swallowed.

Can frogs eat venomous spiders? Yes, frogs can eat venomous spiders. When a frog eats a venomous spider, it typically immobilizes and swallows the spider before it can bite. Still, sometimes frogs get bit. A bite from a highly venomous spider can seriously harm, or even kill a frog.

Do toads eat spiders? Yes, toads eat spiders. When a toad sees a small enough spider, it launches its long sticky tongue to catch the spider. The spider is then immobilized and quickly swallowed before it can bite, although bites do happen on occasion.

Do tree frogs eat spiders? Yes, tree frogs eat spiders. They typically catch and swallow them quickly, before they have time to bite.

Conclusion

Frogs are generalist predators that will eat almost any prey they can fit into their mouths. They do eat spiders, however, they do not intentionally seek out spiders to prey on.

Rather, they only eat them opportunistically when they get the chance.

Photo credit: Richard Thomas, via Flickr.

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