【Veterinarian-Written】Why Do Cats Eat Insects? A Veterinarian Explains Safe vs. Dangerous Insects and How to Handle It

Have you ever seen an insect get inside your house and your beloved cat chase after it intently? Sometimes, in their obsession, the insect ends up inside the cat’s mouth. You may certainly feel anxious, wondering, "My cat chased and ate an insect—will they be okay?" In reality, cats chasing insects is a result of their hunting instincts and curiosity, and it is not unusual for them to eat one. In most cases, it passes without any issues, but there are some insects you need to be careful about. In this article, we will explain the accidental ingestion of insects.

Why do cats eat insects?

Because their hunting instinct is stimulated

We can explain why cats eat insects based on the structure of their brain. Humans and cats generally share the same basic brain structure: the cerebral cortex, which analyzes information; the limbic system, which governs emotions and instincts; the frontal lobe, which controls emotions and governs reason; and the brainstem, which is involved in maintaining life. While the human frontal lobe is exceptionally developed, that of a cat is not.

Consequently, they cannot fully control their instincts and curiosity, so when they see an insect, a switch flips: "What is that? It’s fun! I’m going to catch it!" The instinct to maintain life appears particularly strongly, and the hunting instinct—to catch and eat prey—is a behavior constantly observed even in indoor cats. This hunting instinct often does not align with hunger, so it does not necessarily mean they are "catching and eating the insect because they are hungry."

They eat them while playing out of curiosity

Because a cat’s instincts are dominant over its reasoning, they are interested in things that move. Wild cats catch prey to secure food, so they perform actions to kill in an instant. This is taught to them by their mothers.

However, in the case of indoor-raised cats, they have not learned the behavior for capturing prey, so they treat the prey like a toy. After catching an insect, they might release it from their mouth and roll it around. Then, while it's in their mouth, they end up eating it.

Because they are intrigued by the insect's movement or sound

Insects fly around, hide in shadows, and make buzzing or scratching sounds even when they are out of sight. That activity immediately ignites the cat's curiosity and hunting instinct. Are there any insects in your home that move like this? You might think of spiders, flies, mosquitoes, or cockroaches—insects we would rather not see. These insects become interesting prey for a cat.

They may recognize them as food

To a cat, a small insect is very interesting prey. It is thought that cats do not see the insect as a toy, but rather as an object of the hunt—that is, as prey to be eaten. Therefore, it can happen that once it enters their mouth, they eat it. Note, however, that indoor cats are well-nourished, so "eating an insect" does not mean they are "replenishing missing nutrients."

Which insects are safe for cats to eat?

Which insects are dangerous for cats to eat?

Insects that are venomous

Bees, centipedes, venomous spiders (such as the redback spider), and the larvae of venomous moths (such as the oriental moth or brown-tail moth) require caution. You should also be careful of other venomous creatures that live in your region.

With these insects, the issue is more about being "stung or bitten" while trying to catch them than the act of "eating them."

Insects that may have insecticide or pesticides on them

Even if the insect itself is non-toxic and harmless, there is a possibility that it has insecticides or pesticides on its body or inside it. If you have used insecticide in the room or used a spray, high concentrations of insecticide components may be on the insect's body. Furthermore, in products like cockroach exterminators, the components are ingested into the cockroach's body.

Most insecticides are pyrethroids, which are low-toxicity to cats because they are quickly broken down in an animal's body. However, if a large amount is ingested, symptoms such as vomiting, diarrhea, and drooling may appear.

What requires caution are garden insecticides and pesticides; organophosphate or carbamate-based ones can cause poisoning. You need to be careful if you use such products at home or if you live in an area where agriculture is active.

My cat ate an insect! What should I do first?

First, identify the type of insect

If possible, take a photo or save the insect's remains if they exist. You can look up the type and toxicity of the insect via image searches or similar methods. It is also good to record the location—if it was outdoors, what kind of place it was, and the condition of the surrounding plants.

Do not force them to vomit

Absolutely do not force them to vomit on your own judgment. If you search on the internet, you will find methods to induce vomiting (such as making them drink a large amount of water, salt water, or hydrogen peroxide), but these methods are not recommended because they have a high possibility of causing poisoning or gastrointestinal damage. Always consult with a veterinary clinic and seek an examination if necessary.

Observe them afterwards

If your cat has eaten an insect, keep a close watch on them for a full day. If you see the following symptoms, consult a veterinary clinic immediately.

If stung by a bee, it can cause anaphylactic shock, which can be life-threatening. Be aware that in such cases, respiratory distress, open-mouth breathing, or loss of consciousness can occur within 30 minutes. Symptoms of poisoning from pesticides or similar substances also appear quickly, within tens of minutes to a few hours. Also, even if the insect itself is harmless, if your cat is infected by a pathogen or parasite carried by the insect, symptoms may appear after a day or even a few weeks.

Go to a veterinary clinic if you see these symptoms

Persistent vomiting or diarrhea

Even if the insect itself has no toxicity, they may become ill due to pathogens or parasites. In that case, the symptoms will continue unless the cause is treated. Bacterial infections can cause gastroenteritis, leading to persistent vomiting or diarrhea. Vomiting and diarrhea can also be caused by parasitic infections.

Excessive drooling

If they ingest an insect with pesticides or insecticides, it may cause poisoning. Large amounts of drool appear shortly after ingestion. Additionally, drooling occurs if they are stung in the mouth by venomous insects such as bees or caterpillars. This is a highly urgent symptom due to the possibility of poisoning or anaphylactic shock. See a veterinarian immediately.

Swelling of the mouth or face

The face or mouth may swell if stung by venomous insects like bees, or due to an allergic reaction to venom or chemicals. This is often accompanied by itching or pain, and because the overall condition could worsen afterward, you should seek medical attention promptly.

Difficulty breathing

It is known that in cases of anaphylactic shock in cats, respiratory distress manifests more severely compared to dogs. If they seem to have difficulty breathing or are open-mouth breathing, they may be experiencing severe symptoms. Seek medical attention immediately. Be especially cautious if stung by a bee, as this can lead to respiratory distress due to anaphylactic shock.

Lethargy or unsteadiness

These symptoms appear if neurological symptoms arise due to venom or chemicals, or if blood pressure drops due to anaphylactic shock. The overall condition is quite serious, requiring immediate medical attention.

Seizures

Many pesticides and insecticides act on the nervous system. If such chemicals are on the insect, neurological symptoms like seizures may occur. Seizures can also happen if blood pressure drops due to anaphylactic shock, causing a decrease in blood flow to the brain. Immediate medical attention is required.

Possible involvement of venomous insects or chemicals

Most of the symptoms described above appear when venomous insects or chemicals are involved. Specifically, if stung by a bee, "respiratory distress, facial swelling, or impaired consciousness" within 30 minutes may indicate anaphylactic shock from bee venom. This is a life-threatening situation, so if stung by a bee, see a vet immediately. If the cat has clearly eaten an insect contaminated with chemicals, veterinary care is also necessary.

How can I keep my cat from eating insects?

Prevent insects from entering through screen doors and windows

To prevent accidental ingestion, you need measures to keep insects physically out of the room. Insects enter through screen doors, windows, and entryways.

Therefore, you must keep windows and doors closed, choose screen doors with fine mesh, and immediately replace them if there are any holes. Using pet-safe repellents may also be effective.

Keep the room clean

Pests like cockroaches multiply using human food scraps as a food source. Keep the interior clean to create an environment where cockroaches struggle to survive.

Do not leave food or garbage out

Leaving food or household waste out will attract flies and cockroaches. Protect leftovers so insects cannot get to them, or dispose of them if you are not going to eat them.

Also, put household waste into plastic bags, tie them shut, and dispose of them. Put garbage into a container with a lid to prevent insects from getting in. Be sure to throw out the garbage on collection day and do not let trash accumulate.

Be careful with the use of insecticides

Most insecticides used indoors use ingredients that are harmless to cats, but the concentration can become high in a closed room. When using insecticide, ventilate the room and ensure it does not get directly on the cat.

Garden insecticides sometimes use chemicals that can cause poisoning. When purchasing, read the usage instructions carefully and try to choose products that are less harmful to animals.

Do not chase insects in front of the cat

It is said that cats perceive humans as big cats. It is also thought that they view their owners as their own mother or as a cat that cannot hunt.

Therefore, if you chase an insect in front of the cat, it may excite them even more, thinking "they found prey for me." If you find an insect, do not chase it in front of the cat and try to act as quietly as possible.

Incorporate play that satisfies the hunting instinct

Because a cat's instincts are dominant, they will feel stress if those instincts are not satisfied. If you satisfy their hunting instinct through regular play, they can be sufficiently satisfied without chasing insects.

Cats often love cat teasers and balls; you can have fun playing with them by imitating insect movements or hiding toys. Educational toys that release food when rolled can also be toys where cats can enjoy hunting while using their brains.

The important thing to remember during play is to play together with your cat. Since cats can get bored quickly or run the risk of accidentally eating the toy, always play together, and put the toy away when finished to avoid accidental ingestion.

Do indoor cats still eat insects?

Even cats with little contact with insects have an instinctive habit of chasing them. It is more likely that they end up eating them while playing rather than eating them out of a desire for food.

Insects can enter even through the small mesh of a screen door. They also enter from entryways, windows, balconies, or other places connected to the outdoors. A cat's curiosity will be piqued by any insect they have never seen before.

Is eating insects a sign of illness in a cat?

Eating an insect alone cannot be judged as a sign of any specific disease. It is unlikely that they would exhibit the symptom of eating only insects.

However, you should be cautious if they suddenly start eating things they usually wouldn't (including foreign objects like insects), have an abnormally increased appetite, lose weight despite eating, vomit more frequently, or show changes in behavior or personality. These can be symptoms of serious diseases such as endocrine disorders (e.g., thyroid issues) or brain disorders. In such cases, consult a veterinarian.

Summary | Cats eating insects is not unusual

Cats eating insects occurs due to their hunting instinct and curiosity. Eating an insect itself usually passes without any problems. However, caution is necessary if they eat venomous insects or insects that have been contaminated with pesticides or insecticides.

If you "don't know what kind of insect they ate," "symptoms are appearing," or "there is a possibility that chemicals are involved," do not make your own judgment—consult a veterinary clinic immediately.