Grass eating is a common behavior in dogs, including Chihuahuas. In fact, a survey of 72 dog owners conducted in 2008 found that 79% of dogs ate grass. While this study is relatively small, it reveals just how common this behavior is among man's best friend.
From an owner's perspective, seeing your Chihuahua eat grass can raise some questions
- Is my Chihuahua sick?
- Is grass eating harmful?
- Is it normal for Chihuahuas to vomit afterwards?
- Why exactly does he eat grass?
- How do I stop my Chihuahua from devouring my lawn?
These are all reasonable questions to ask, and while this topic is highly debatable, we're going to try and answer them.
Is it Normal for Chihuahuas to Eat Grass?
With roughly 3 out of 4 Chihuahuas exhibiting this behavior during their lifetime, most experts agree that grass eating is normal behavior. Some Chihuahuas are finicky and prefer specific varieties like fescue or ryegrass, while others are less discriminate and willing to eat any grass they can get their paws on. Regardless, you've probably seen your pint-sized companion eat grass at least once. It's normal behavior exhibited by most dogs, both big and small.
Understanding why Chihuahuas eat grass, however, is more difficult. We've learned a great deal about man's best friend since we first domesticated them some 15,000 years ago, but we've yet to draw a conclusive answer to this question.
Theory #1) Digestion
One of the most popular theories is that dogs, including Chihuahuas, eat grass to induce vomiting and assist in digestion. When a Chihuahua has an unset stomach, intestinal blockage, gas, or other digestive issues, he may eat grass to induce vomiting and offer relief -- at least that's what some experts believe. Upon ingestion, the indigestible plant matter tickles the throat and stomach, causing him to vomit. Dogs are more likely to vomit after eating whole blades of grass without chewing it (you can see the blades in the vomit).
But not everyone is on board with this theory. Researchers from the University of California, Davis conducted an online survey of 1,571 dog owners, in which they discovered that only 22% of dogs regularly vomited after eat grass, and only 8% of dogs had exhibited signs of illness prior to eating grass. If Chihuahuas eat grass to induce vomiting and improve digestion, these numbers would likely be higher. Granted, that's only a single study, with a limited data pool nonetheless, but many experts reject this theory.
Theory #2) Nutritional Deficiency
Another theory is that Chihuahuas eat grass is because they suffer from a nutritional deficiency. If your Chihuahua isn't getting the necessary nutrients he needs in his regular diet, perhaps he'll look for alternative sources, such as your lawn. Grass doesn't offer the same delicious flavor as premium chicken/beef/lamb dog food, but it still contains key nutrients such as fiber, vitamin A, vitamin C, vitamin E, vitamin B6, iron, zinc, niacin, thiamine, riboflavin and selenium.
The problem with this theory is that eating grass offers little-to-no nutritional value for Chihuahuas. Grass consists mostly of cellulose, which passes right through the digestive tract without the nutrients ever being absorbed. Chihuahuas benefit from the fiber, which softens stools and eases bowel movements, but they don't benefit from the vitamins or other nutrients in grass. Cows, deer, goats and other grazing animals have multi-chambered stomachs containing microorganisms known as archaebacteria, allowing them to digest grass. Humans and our canine counterparts, on the other hand, have single-chambered stomachs that prevents such complex digestion from taking place.
Theory #3) Intestinal Parasites
A third theory is that Chihuahuas eat grass to purge intestinal parasites, such as roundworms, whipworms, hookworms and tapeworms, from their bodies. The high fiber content of grass could flush out such parasites. According to Kansas State University's Veterinary Health Center, approximately 34% of all dogs in the United States are infected with gastrointestinal parasites. In the southeastern states, this number jumps to 54%. If a Chihuahua suffers from an intestinal parasite, perhaps he'll eat grass to vomit and purge the parasite from his digestive system.
But if your Chihuahua is on a worm preventative medicine -- like he should be -- there's no reason for him to purge intestinal parasites by eating grass, right? Some experts believe dogs inherited this trait from their wolf ancestors (the modern-day dog shares 99.8% of its DNA with wolves). Wolves preyed on grass-eating animals like squirrels, foxes, gophers and deer, eating their entire bodies and grass-filled stomachs.
Furthermore, an article published in the Journal of Veterinary suggests that feral wolf mothers who eat grass during pregnancy are more likely to give birth to grass-eating puppies. So even if your Chihuahua is parasite-free, he may continue to exhibit this behavior because it's hard-wired in his DNA.
Theory #4) Boredom
Maybe your Chihuahua eats grass simply because he's bored. Chihuahuas need regular mental and physical stimulation. If you don't give it to them, they'll become bored and seek other ways to pass the time, such as chewing on carpet, tearing up rolls of toilet paper, barking at passing cars, biting their nails, and eating things they normally wouldn't, such as grass.
This problem is easily avoided by providing your Chihuahua with regular exercise, preferably at least 30 minutes per day. You can also keep your Chihuahua busy throughout the day by providing him with toys. Puzzle toys are particularly useful for keeping dogs occupied. Some feature hidden compartments in which a treat is placed. In order to retrieve this treat, the Chihuahua must knock the toy around until it falls out. The only downside with puzzle toys is that most dogs learn how they work after a couple of times, allowing them to retrieve the treat with little effort.
Potential Dangers and Problems Associated with Eating Grass
The risk of any major health problems developing in Chihuahuas from grass eating is generally low. Though indigestible with virtually no nutritional value for dogs, grass is a natural and safe substance. But grass could be harboring other things which are harmful to Chihuahuas.
Many homeowners, business owners and municipalities treat grass with pesticides, which a Chihuahua may inadvertently consume when eating grass. In fact, we use more than one billion pounds of the stuff each year -- and that's only here in the United States. Pesticides often contain toxic chemicals such as ammonia, arsenic, benzene, chlorine, dioxins, formaldehyde and methanol.
When consumed by a Chihuahua, these chemicals can cause serious illness or death. A study published in the January 2012 issue of the Journal Environmental Research found that exposure to lawns professionally treated with pesticide was linked to 70% higher risk of canine malignant lymphoma (CML). This study focuses specifically on professional-grade pesticide, but even consumer-grade pesticides are toxic to dogs and should be avoided.
Even if the grass is pesticide-free, it may contain fertilizer that's toxic to dogs. According to the Pet Poison Helpline, ingestion of fertilizer is one of the top 10 most frequently reported poisonings in dogs.
Most grass/plant fertilizers contain three primary ingredients: nitrogen, phosphorus and potassium. Others, however, may other also contain copper, zinc, boron and molybdenum, as well as herbicides, pesticides and fungicides. Due to their small size, Chihuahuas are particularly susceptible to poisoning from lawn fertilizers and pesticides.
Don't allow your Chihuahua to eat grass if it contains mulch, especially cocoa mulch. Used in landscaping and gardening projects, cocoa mulch contains shells from the cocoa bean. It has a fragrant aroma, similar to chocolate, that attracts animals. But just like chocolate is toxic to dogs, so is cocoa mulch. They both contain the toxic compound theobromine, which dogs cannot properly metabolize.
Symptoms of cocoa mulch poisoning in dogs are the same as chocolate poisoning, which we discuss in the article Foods Your Chihuahua Shouldn't Eat.
#4) Other Toxic Chemicals
There's also the possibility of other toxic chemicals like antifreeze leaching onto the grass. The main ingredient in many automotive antifreeze products, ethylene glycol, is highly toxic to dogs, with a lethal dose being just 2-3 ml/lb. If your Chihuahua weighs five pounds, consuming as little as 10-15 ml can be fatal.
In 2012, manufacturers added a bittering agent to make their antifreeze products less appealing to pets and animals. Earlier generations of antifreeze had a sweet taste and odor, attracting animals to the toxic automotive chemical. But even with the bittering agent, antifreeze remains a leading cause of pet poisoning. The Humane Society recommends choosing antifreeze with propylene glycol instead of ethylene glycol, which is still toxic but safer than its counterpart.
#5) Toxic Plants
Being that none of North America's common varieties of lawn grass are toxic to dogs, your Chihuahua probably isn't going to get sick from eating grass alone. If he consumes a plant, though, it could be a different story.
There are hundreds of native plants that can make your Chihuahua sick when ingested, some of which include azaleas, cyclamen, lilies, oleander, daffodils, lily of the valley, aloe vera, and tulips. And according to a poll of 2,000 cat and dog owners conducted by the insurance firm More Than, 1 in 12 pets has eaten a toxic plant.
#6) Sharp Grass
Just because grass isn't toxic doesn't mean it's safe for your Chihuahua to eat. Found primarily in the western half of the Unites States, foxtail grass (Alopecurus, Bromus madritensis, Hordeum jubatum, and Setaria) has razor-sharp barbed seed awns that can pierce holes in the tissue and organs when ingested.
Chihuahuas can even injure themselves simply by walking on or near foxtail grass without ever ingesting it. The sharp seed awns can embed themselves into the skin, causing infection and/or migrating closer to an organ.
While some experts theorize that dogs eat grass to purge parasites from their system, this behavior could actually expose our canine companions to new parasites. Roundworms and hookworms are transmitted through the feces of an infected host, so if your Chihuahua eats grass containing feces -- not pleasant but it happens -- he too could become infected.
The risk of parasitic infection is low, especially if your yard is inaccessible to other dogs, but it's still something owners should be aware of if their Chihuahua isn't on a worm preventative medicine like Trifexis.
#8) Intestinal Blockage
Another problem with grass eating is the potential for an intestinal blockage. As previously mentioned, Chihuahuas cannot digest grass, so it simply passes through their digestive system without ever being broken down. If a Chihuahua eats too much grass, though, it may accumulate inside their intestines, preventing food from passing through. Intestinal blockages such as this can be fatal if left untreated. The obstruction prevents blood from reaching the gastrointestinal tract, resulting in necrosis of tissue and perforation.
#9) Tooth Decay
When you think of hazards associated with grass eating, tooth decay probably isn't at the top of your list. However, grass contains high concentrations of silica (silicon dioxide) that can wear down the enamel of your Chihuahua's teeth, causing decay and subsequent oral problems.
When to See a Veterinarian
You don't have to rush your Chihuahua to the local veterinarian just because he ate a mouthful of grass. As long as he didn't consume any toxic chemicals or plants in the process, it should pass through his digestive system, regardless of whether he vomits afterwards.
But you really don't know what substances are lingering on your grass, nor do you know how your Chihuahua will react to those substances. Watch your Chihuahua closely and take him to the nearest veterinarian if he exhibits any of the following symptoms: lethargy, disorientation, bloody stool, bloody urine, constipation, diarrhea, tremors and seizures. These are all serious symptoms that could indicate exposure to a toxin.
If you believe your Chihuahua has eaten grass with pesticides, fertilizers or other toxic chemicals -- but he's not exhibiting any symptoms that require immediate medical attention -- contact either the APCA's Animal Poison Control Center (APCC) at 1-888-426-4435 or the Pet Poison Helpline at 1-800-213-6680. The APCC charges a $65 consultation fee, while the Pet Poison Helpline charges a $39 consultation fee. Both services are available 24 hours a day, 7 days a week.
How to Stop Your Chihuahua from Eating Grass
While common behavior among dogs, many owners prefer their Chihuahuas to not eat grass. It exposes them to unknown chemicals and substances; increases the risk of intestinal blockages; and it can lead to tooth decay. So, how do you stop your canine companion from feasting on your lawn?
Walk Your Chihuahua on a Leash
Start by walking your Chihuahua on a leash instead of allowing him to roam free. Most Chihuahuas know they shouldn't be eating grass, so they'll sneak out of their owner's sight to engage in this activity. But if you walk your Chihuahua on a leash, you can supervise him the entire time. Besides, allowing your Chihuahua to go outside unsupervised places him at risk for serious injury from snakes, hawks, foxes and other predators.
Assuming your Chihuahua is wearing a harness instead of a collar, pull back on the leash when you see him eating grass. You don't want to create a tug-of-war scenario in which your Chihuahua thinks this is a game. Rather, pull back slowly and gently with just enough force to interrupt his green meal.
You should only pull back on your Chihuahua's leash if he's wearing a harness. When wearing a collar, the pulling force is exerted directly on the neck. This increases the risk of injury such as collapsed trachea and fractured vertebrae. A harnesses, however, distributes the pulling force evenly safely across the dog's torso.
Divert Your Chihuahua's Attention
If you see your Chihuahua trying to eat grass, divert his attention elsewhere. Like all dogs, Chihuahuas have a short attention span, making this an effective tactic to stop grass eating.
Here are some tips to divert your Chihuahua's attention:
- Use a recall command command like "come here boy/girl" to catch your Chihuahua's attention and interrupt his grass eating.
- Sit and heel are also commands that can stop this grass eating and other unwanted behavior.
- You can divert your Chihuahua's attention away from grass eating with toys. Chihuahuas are typically too small to retrieve frisbees, but tennis balls are perfect for these pint-sized companions. Toss a tennis ball across the yard while telling your Chihuahua to "go get it! Chihuahuas possess an instinctual drive to chase varmints and small moving objects, so when they see a tennis ball bouncing in the opposite direction, they'll dart towards it.
- While effective at diverting a Chihuahua's attention, treats shouldn't be used because they essentially reward his grass-eating behavior.
Positive Reinforcement, Not Punishment
Don't scold or otherwise punish your Chihuahua for eating grass. Punishing him for an instinctual behavior he likely inherited from his ancestors is ineffective and counterproductive. Your Chihuahua may act out in response to being punished, or he may eat grass the next time he wants your attention. To stop your Chihuahua from eating grass, focus on attention diversion and positive reinforcement through basic obedience commands.
And if you allow your Chihuahua to eat grass, make sure it's not treated with any pesticides, fertilizers or other chemicals. Some canine experts even recommend making a special grass or herb garden that's designed specifically for your dog.
We may never know why Chihuahuas eat grass. Theories such as digestive problems, nutrient deficiency, intestinal parasites and boredom are all possible, but there's no definitive answer. We do know that grass eating is a common behavior exhibited by most dogs and it rarely causes any need for concern. Just keep a close eye on your Chihuahua to see if he exhibits signs of an underlying illness.
Is your Chihuahua a grass eater? Let us know in the comments section below!