How Do Dogs Know What Is And Isn’t Food? (Explained By Trainer)

How Do Dogs Know What Is And Isn't Food

As dog owners, we’ve all probably seen our dogs go nuts over a piece of steak that we dropped on the ground, or watched them pick up the trail for something that smelled tasty only to have them lead us to the garbage cans.

Other times we’ve watched them smell curiously at a flower or bug, wondering if they’d try to eat it, only to watch them walk away with disinterest. But how do our dogs know what is and isn’t food?

Dogs rely on their sense of smell to determine what is and isn’t food, but a lot of that information also comes with life experience. Puppies and younger dogs are more likely to eat things that aren’t food due to their natural curiosity, and dogs with medical or behavioral issues may also consume inedible objects.

Below we’ll discuss how dogs use their noses and keen sense of smell to help them determine whether something is or isn’t food, and why they may still consume something that we humans may consider inedible.

We’ll also look at the differences between puppies and adult dogs and how they determine what is and is not edible, and why some dogs tend to eat things that are not inedible. Finally, we’ll go over some tips to help keep your pup from eating inedible objects.

How Do Dogs Know What Is And Isn’t Food?

Dogs rely mainly on their sense of smell when it comes to identifying what is and is not food. But to a dog, their definition of edible can be very different from our definition of edible! In that respect, dogs do not naturally know what is and is not food until after they have attempted to eat it.

There are certain things that may smell bad to a dog (such as very sour foods like lemons) and the dog may take a sniff and then avoid the item completely. There are even certain dog breeds that tend to be much pickier about their food than others.

Other items may smell interesting enough to the dog that they will usually then try to take a small bite out of the item to see if it’s worth consuming, or it may smell so good that they dive right in and eat it all in one gulp.

But smell will almost always be the first sense a dog uses to determine what is and isn’t food.

How A Dog Uses Its Nose

A dog’s sense of smell is up to 100,000 times stronger than a human’s sense of smell, so it’s no wonder they use their nose as their primary way of identifying whether something is edible! Compared to people, who have around 9,000 taste buds, a dog only has around 1,700 so taste is not usually a good way for them to determine if something is food or not (though that doesn’t make them any less interested in eating!).

Dogs may enjoy the taste of certain things (they are especially prone to eating salty things as a result of genetics and evolutionary history), but if the item doesn’t smell enticing (or the dog isn’t curious enough to investigate it) then he usually won’t try to eat it.

Because of this strong sense of smell, dogs are also likely to eat things that we humans think are past their “best by” date, or items in which we would never think of consuming.

As many owners know, dogs try to eat all sorts of things we might find disgusting, from rancid meat that’s been left in the trash for a few days to the feces of other dogs or other animals like cattle and geese.

This keen sense of smell can also cause dogs to eat things that otherwise don’t even really have a smell to us, such as bird seed or a lizard that’s lounging on the patio wall. If it smells interesting enough to them, they may just eat it!

Differences Between Puppies And Adult Dogs

While puppies have a good sense of smell, depending on their age it might not be as developed as an adult dog’s sense of smell. Puppies also tend to be more curious by nature, and investigating things with their mouths is usually one of their favorite activities (particularly during the teething stage).

Due to this natural curiosity and a general lack of world experience, puppies are also more likely to consume things that aren’t food and that an adult dog would probably not eat. In the eyes of a young and inexperienced puppy who is just discovering the world, everything has the potential to be a tasty treat!

It is through this learning stage that they begin to understand what is and is not food (or at least what items are more fun to chew on than others), but we can help guide them in the right direction by providing them with age-appropriate chew toys and puppy proofing our homes to keep them out of things they shouldn’t be eating.

Will Dogs Eat Something That’s Not Edible?

Yes, dogs will absolutely eat something that’s not considered edible! Dogs may use their noses to determine what smells are enticing and what may or may not be food, but just because something doesn’t smell like food doesn’t mean that a dog will avoid eating it.

Dogs may eat things that are considered inedible for one of the following reasons:


Many dogs tend to be very curious in nature, particularly puppies and dogs in their adolescent years.

During these ages, they are exploring and learning about the world around them, and one of the ways in which they do that is through their mouths.

A curious pup may chew on or eat something normally considered inedible, especially if the item has a unique texture or makes a fun sound.


Similar to curiosity, dogs may eat something inedible if they are bored and left to their own devices. A bored dog is a dangerous dog, and bored dogs are often the poster children of eating things they shouldn’t.

A bored dog may find anything and everything to chew on or eat to try and alleviate their boredom. Providing appropriate physical and mental enrichment for your dog can help prevent any boredom issues and keep them from eating things they shouldn’t.

Behavioral Reasons

Dogs who suffer from high stress or extremely high energy may chew on or eat things that are inedible as an outlet for that anxious energy. Dogs who have been rewarded (even unintentionally) for chewing on or eating an inedible item previously may also be more prone to chewing on or eating other inedible objects.

They may also increase the frequency of eating certain inedible objects if they were rewarded previously but that reward was suddenly taken away, such is frequently the case for owners who accidentally create behavior patterns in their dogs.

A good example of this is an owner who yells at and chases around the dog who takes facial tissue from the trash, or a book from their owner’s table. The dog, who originally may have only taken the items because they were curious or bored, has now learned that it’s great fun to take those items and have their owners chase them around.

If the owner suddenly stopped doing that and did not offer the dog an alternative behavior to do, then the dog may ramp up the behaviors and potentially try to consume the object or start grabbing other objects.

If you find that your dog falls into this category, a local dog trainer can help you create new behavior patterns that don’t involve eating inedible objects!

Medical Reasons

While most are relatively rare in dogs, there are a few medical conditions that can cause a dog to eat inedible objects. Clinical separation anxiety (diagnosed by a veterinarian or a specialized canine behaviorist) can cause a dog to chew on or consume things that are inedible.

Even dogs who suffer from non-clinical anxiety may display abnormal chewing and eating habits when in states of high stress.

They often do this without thought as to how much they are consuming, or what they are consuming. Some dogs may even attempt to chew through door frames, walls, or windows in an attempt to escape their home or the source of their anxiety.

Some dogs can also suffer from the medical condition pica and will eat anything and everything. These dogs may have very specific items that they become “obsessed” with eating, such as cotton balls or shoelaces, or they may not be as discriminating in their eating habits

Nutritional deficiencies can be another source of abnormal and excessive eating habits, and dogs who obsessively eat dirt, rocks, or other nutrient-rich objects may be suffering from a lack of vital nutrients, vitamins, or minerals in their diet.

If you suspect your pup has any of these conditions, you should reach out to your vet to have them evaluated.

How Do I Stop My Dog From Eating Something They Shouldn’t?

Whether you are needing to stop your curious puppy from getting into the trash, or you are working on helping reduce your dog’s tendency to eat things when they are bored or anxious, there are a few things you can do to help stop them from eating things that they shouldn’t.

Teach “Leave It”

To teach “Leave It”, you can start by placing a piece of food on the floor and then standing right next to it. As your dog attempts to pick up the piece of food, you can cover it with your foot and say “Leave It”. After your dog backs away, remove your foot, and if they attempt to get the food again, repeat the “Leave It” cue and step over the treat again.

As soon as your dog does not attempt to immediately go towards the piece of food on the ground, praise and reward them with a treat from your hand before picking up the piece of food on the ground. Alternatively, you can also hold a piece of food in the palm of your hand and hold it out to your dog.

If your dog attempts to take it from your hand, quickly close your hand and say “Leave It”. Once your dog stops immediately going towards your hand when you open it, praise and reward them with the treat. Repeat this frequently, gradually amping up the difficulty of what you are asking your dog to leave alone.

While this cue is most beneficial if you are there to watch your dog, with repeated usage and helping your pup develop good impulse control, it is likely that teaching them this will also reduce the chances of them eating something they shouldn’t even when you aren’t around.

Provide Alternatives

For curious or bored dogs, anything and everything is potentially chewable and edible. Providing your pup with toys, chews, and treats that are appropriate for dogs will allow them to engage in their natural curiosity and help curb their boredom in a safe way.

Puzzle toys, snuffle mats, and food-stuffed toys are all good alternatives to other potentially unsafe objects (DIY enrichment is another great option for many owners). Just make sure that whatever item you give your dog is appropriate for their size and chewing ability, and that it is not small enough for them to swallow or break into pieces.

If you have an aggressive chewer, a high energy dog who gets bored easily, or a dog suffering from anxiety, it’s likely you’ll have to have several types of alternatives as they will probably tear up their toys pretty quickly.

As the video below explains, dogs need to chew, but to keep them interested in very specific items, try rotating toys, and make sure to find tough toys that take longer to break apart.

Prevention Is Key

The best thing you can do for a dog who tends to eat inedible objects is to prevent them from getting access to those objects in the first place. There are a lot of common household things that are incredibly toxic to pets, and accidental ingestion from a curious pup is common.

Keeping anything that your dog could potentially find enticing up and away from their reach is important, especially if the items smell good or mimic the smell of food objects that the dog is used to eating. Don’t forget about keeping your dog’s items up and away when it’s not feeding time, too!

As scavengers, dogs can be prone to overeating when food is available at all times and this can lead to health problems such as obesity, diabetes, or pancreatic and kidney issues.

As much as our dogs love their treats and as much as we love giving them treats, it’s important that everything be done in moderation to help keep our pups happy and healthy.

Closing Thoughts

Dogs rely on their sense of smell to help them determine whether something is or isn’t food, but they frequently consume things that we humans often consider inedible.

Sometimes dogs will eat things that are dangerous for them, and methods should be taken to help keep your pup from doing this.

A dog’s idea of food can be much different from our idea of food, and it’s up to us to help make sure that what they are putting in their mouths is safe!

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