What makes for a great dog walk? Is it a power walk through your neighborhood with your Fitbit tracking your every step? Nope. That is YOUR walk. What your dog wants is an opportunity to just go where he wants to go and do what he wants to do. The ideal ‘walk’ for your dog is a time to just run free … time to just “dog” … to roll in the grass, to sniff, to dig, to chase critters …. The term decompression walk was defined by Sarah Stremming as “a walk where the dog is allowed freedom of movement in nature”. Decompression time for your dog has the same benefits as it does for us humans. Studies have shown that sniffing actually lowers your dog’s pulse rate and reduces their stress.
The best experience for any dog is time spent off-leash. If you plan to allow your dog to run off leash, there are some very important things to consider before you head out the door:
Are there ordinances in your area about off leash dogs? If so, make sure that you are going to off-leash friendly areas. Don’t be the dog owner that lets your dog off leash in on-leash only locations.
Make sure that your dog has a bomb-proof recall before letting your dog off leash in an un-enclosed space. Nothing good is going to come from this.
Be aware and respectful of others. Keep this in mind and prevent your dog from harassing others (remember that bomb-proof recall in #2). Not every dog wants to be your dog’s friend and not every person is comfortable around dogs … and they have the right to enjoy that space without being harassed by an off-leash dog.
But, what if you don’t have off-leash zones in your area, your dog doesn’t have a solid recall yet or she isn’t good with strange dogs or people?
Sniffspot is an online service that lists private “dog parks” that can be rented for solo use. These spaces may be as simple as someone’s backyard or they could be acres and acres of fenced land. Sniffspot is growing, but you won’t find spaces in every location.
No Sniffspots available in your area? No worries.
Even if you can’t find a safe space for a true off-leash experience, you can still get many of the benefits of off leash time through a more controlled Sniff Walk, or Sniffari. A sniff walk is a walk during which your dog is allowed the freedom to be a dog while still safely controlled with a harness and long line.
Sniff Walk How-To’s:
Long line. A long line is just a extra long leash that comes in lengths anywhere from 10 to 100 feet. They are great for training recalls, but make the perfect sniff walk leash. You can purchase a long line or simply make your own. Tie a clip to one end of a length of rope to hook to your dog’s harness. Then tie a loop at the other end for a handle.
Harness. A harness is much safer than a collar for any walk. Look for a harness that allows full range of motion. For example, harnesses with a band across the chest restrict shoulder movement.
Hands free leash system (optional). A hands-free belt to attach your long line to works great to free up your hands. Now you can dispense treats or handle the line to keep it from getting tangled.
Treat pouch with treats or kibble. If your dog has never been on a sniff walk, you may need to toss a few treats into the grass/bushes to encourage him and let him know that it is okay to sniff. Instead of treats, toss the food bowl and take your dog’s meal along to scatter feed in the grass.
Poop bags. Clean up after your dog. Do not allow your dog to damage/destroy private or public property – including digging, crushing plants, etc.
I do not recommend using a retractable leash for several reasons:
First, they are dangerous. Many a dog owner or bystander can attest to retractable leash injuries such as rope burns, cuts, and even amputations. If you drop the leash, many dogs are terrified by the handle “chasing” them – making them harder to catch or, worse, causing them into run into traffic in an effort to escape. Finally, our goal is a relaxing walk and retractable leashes maintain a constant tension on the line which is not relaxing for the dog.
How do you find a safe space for a Sniff Walk?
If you live in a rural area, you probably don’t need to look too far to find a wonderful enclosed space for you dog to explore. But what if you live in a more urban area? Here is how you can locate a safe place for a sniffari.
First, set Google Maps or Mapquest to ‘satellite’ mode and type your home address into the search box.
Next, look for green spaces within easy walking or driving distance. Yes, you may need to drive a bit to find a good location.
Once you have located some potential spaces, check each one to determine if it will fit your needs. On the map below, I have marked potential green spaces in my area.
Check land ownership and local ordinances.
The red zones on the map are great spaces, but, sadly, off limits to dogs. Check your local ordinances for parks and cemeteries. If dog friendly, these make great sniff zones.
The purple and blue zones are all dog-friendly possibilities. The two largest purple zones are filled with fantastic nature trails. However, I have reactive dogs and these trails are often narrow with few opportunities to allow enough space for other dogs to pass by without triggering reactions. Since point of a sniff walk is to allow your dog to decompress, these areas are not good options for reactive dogs. Be sure to keep these kind of things in mind when searching for sniff walk spaces.
The little rectangle towards the top of the map is a tiny dog park. On occasion, I have been able to get this space all to myself, but it not always open and is quite small.
So, that leaves the blue zone. This is a university campus and just happens to tick all th boxes.
Dog friendly (allow dogs and safe)
Easy walk from home (or easily accessible by car)
Plenty of green space and interesting textures, surfaces and smells to explore
Plenty of space to allow my dogs to get the distance they need from triggers
Tons of great places to sniff
Throughout COVID many college campuses and other public spaces have been relatively quiet zones – a definite perk for those of us with reactive dogs. When students and faculty are on campus, however, I simply time my walks for less active times of the day. In general, however, you won’t find owners out on sniff walks spending much time on the sidewalks. We are generally following our dogs across the lawns and checking out the bushes. So it is not too hard to avoid the human crowds.
Other great space options to check into:
Parks and playgrounds
Office parking lots or industrial parks
Beaches and waterfronts
Empty dog parks
Visitor center or rest area
Picnic area or campground
Paths and trails (beware of narrow trails)
*Be sure that you contact the property owner and/or check local laws and statutes before taking your dog onto private property.
So, now that we have the equipment and the space that we need, join us as we take our morning sniff walk!
I choose to take our sniff walks in the morning and bring breakfast along in my treat pouch. I use two-point attachment leashes – long leashes with clips at both ends and multiple rings to allow you to adjust the length of the lead. These give me the versatility of having 4-foot leashes when walking through the neighborhood, and the ability to allow the full 8 feet of line for sniffing.
Once on campus, I can let out the lines. My 8-foot leashes don’t allow for as much freedom as a 15- or 30-foot long line. That said, they do allow me to take everyone out together and maintain control if we encounter groups of people on campus. It is also convenient for me to not have to carry along four separate long lines every day.
Once I lengthen the leashes, the dogs are in charge.
We go wherever they take me and sniff whatever they want and for as long as they choose. One exception: They are allowed to sniff the flowers, but not trample through the beds.
Occasionally, I will toss out a handful of kibble in the grass for them to snuffle. The dogs are in charge here as well. They choose the scatter spots by slowing down and looking back at me. Once they have finished their snuffling, we are off again.
Do NOT try to scatter feed with multiple dogs in the same space without some prior training. Sign up for a consultation with me, or talk to your dog trainer about safety layers that can be used when working with multiple dogs. Never do this if any one of your dogs has even a hint of resource guarding tendencies. Instead, either take your dogs for solo sniff walks or do scatter feeds back at home in separate spaces.
Remember, this is your dog’s walk. You are on his clock and he gets to set the agenda. Go with the flow, enjoy the sights and sounds of nature, take the opportunity to catch up on podcasts or listen to an audiobook … and enjoy !
The old saying “a tired dog is a good/happy dog” once meant that you should engage your dog in as much physical activity as possible to tire him out. At the time, we didn’t realize that we were just building a better athlete, while neglecting our dog’s mental health.
Research now shows that there are many other ways to “tire out your dog” and reduce boredom through various types of enrichment activities.
According to a 2009 study, “Non-domestic, stray and feral animals spend the majority of their time foraging for food. In addition, they must seek out or construct resting areas and avoid predators and other natural hazards. Pet animals on average spend less than 15 minutes per day eating because they do not have to forage for food. The majority of dog breeds were developed for some functional purpose (guarding, herding, hunting, etc.) yet few animals actually participate in these activities, leaving them with no constructive outlet for behavior patterns that are biologically generated.” In fact, studies have indicated that “up to 60 percent of companion dogs don’t even get a regular walk.” (Canine Enrichment)
As early as the 1960’s, zookeepers were beginning to understand the need for enriching the lives of captive animals. Increased enrichment has been shown to reduce stress in zoo and shelter animals, reduce reactivity and increase both physical and mental health. In the 1970’s, Dr. Hal Markowitz, an early pioneer in captive animal behavior, defined the term enrichment as meaning “a synonym for ‘more like nature.’ ” More recently, researchers in Sweden conducted a study with a group of beagles and found that “The experimental animals in our study were excited not only by the expectation of a reward, but also about realizing that they themselves could control their access to the reward. These results support the idea that opportunities to solve problems, make decisions, and exercise cognitive skills are important to an animal’s emotional experiences and ultimately, its welfare.”
In a recently published book on this topic, Canine Enrichment for the Real World, authors Allie Bender and Emily Strong define the term as “Enrichment is learning what our dogs’ needs are and then structuring an environment for them that allows them, as much as is feasible, to meet those needs.”
Canine enrichment is a broad term used to describe methods that enhance a dog’s life and meet its needs. This includes its biological need for nutrition, shelter and medical care. Besides basic husbandry, there are four other categories of enrichment – emotional, social, physical and mental.
Emotional enrichment includes the love, trust and security of a safe and happy home. Social enrichment is met through bonding and play with both humans and other dogs. For human play, think things like fetch, tug, flirt poles, sprinkler games, bubbles and hide & seek.
Physical enrichment is met through exercise. E.g., hikes, parkour, sniff walks, running, playing, and many different types of dog sports.
Mental enrichmentis an activity whereby a dog’s mind is exercised through cognitive and sensory stimulation. Mental and sensory stimulation can be accomplished through things like trick training, puzzles, music, nosework, play, new sights and sounds, etc.
Dogs evolved as predators, foragers and scavengers. Studies are showing us that 24/7 access to a full bowl of food day in and day out is simply not healthy. An alarming number of dogs are overweight or obese – which leads to health problems and a decreased lifespan. (For more information on the problem of obesity in dogs, visit this page.) In addition, it is, simply put, boring. Dogs don’t have much to do during the day – a quick potty break in the morning, a walk when you get home from work and, in between, hours of time with nothing to occupy their minds. Bored dogs, just like bored kids, will invent ways to entertain themselves. Boredom leads to behavioral problems – from barking and inappropriate chewing to separation anxiety and hyperactivity – and can even escalate to reactivity.
One easy way to meet many of your dog’s enrichment needs is through food enrichment. Food enrichment satisfies your dog’s natural instinct to forage, slows down eating to aid digestion and reduce bloat, makes meal times more interesting for picky eaters, provides an energy outlet, reduces stress and anxiety, reduces inclination to chew, bark and dig, etc. In addition, it is a great way to keep your dog occupied after a surgery, injury or spay/neuter when physical activity must be limited.
Did you know that many professional dog trainers provide all of their dogs’ food through training? These dogs never eat from a bowl.
You will hear us telling our clients to “toss the food bowl.” We mean this quite literally. Here are some ideas for how you can join us in tossing the food bowl and enriching your dog’s day through food.
How do I get started with food enrichment? A good first step can be as simple as adding new flavors and textures to your dog’s meals. Add a novel topper to your pup’s kibble – a scoop of yogurt, cottage cheese or pumpkin, cut up apple, pear or banana, freeze-dried liver bits or sardines. When training with minimal distractions, try mixing some frozen green beans, baby carrots or blueberries in with your regular treats.
Now that we have your attention, let’s work toward tossing those food bowls altogether and letting your dog engage in food enrichment activities instead.
Worried about how much food your dog will be getting if you start adding more treats and additional food-related activities to your dog’s day?
Simply take all of the food that your dog is going to get during the day and put it in a single container. This is what you have to work with throughout the day. Use some for training and some for enrichment games. When using non-kibble additions, simply calculate this into the day’s portion and remove kibble to accommodate these new items.
Be Sure to Feed Only Dog-Safe Foods
Before starting any food enrichment activity, be sure that you have a list of foods that are not safe to feed. Read all ingredients lists and consult your list of unsafe foods before using any new food type or new product brand.
Xylitol is used as a sweetener, as a medication and as a way to prevent tooth decay and dry mouth. It is HIGHLY toxic to dogs. Be sure to check labels in your household for items containing xylitol and store them where your dog is not able to get to them.
Food enrichment activities should always be done under close supervision. Take the time to introduce your dog to new activities and teach him how to do it. When your dog is finished with the activity, pick it up and put it away so that your dog does not destroy or ingest it. “Kong” type toys are generally safe for unsupervised crate time. If you are absolutely certain that your dog is not going to ingest things, some food dispenser toys and cardboard tubes/boxes could be another option for your dog.
Rotate activities and toys to keep things new and exciting for your pup.
If you have a multi-dog household, they should be separated for food enrichment activities. This will reduce resource guarding and avoid possible fights. Working alone allows your dog to slow down and really enjoy the activity – rather than having it be a race to finish first. If you plan to do activities without separating your dogs, be sure that you are supervising them closely and watching for any body language that may indicate a problem.
Puzzle (Slow Feed) Bowls
Puzzle bowls are the most basic type of food enrichment. They work well for dogs that are just starting out. Outward Hound, Northmate and PAW5 all make puzzle bowls. If you don’t want to purchase a puzzle bowl, try putting a ball or two in with your dog’s regular kibble to make an obstacle to work around or substitute something like a muffin tin. You can even add water or diluted broth to their food bowl and freeze.
Food Stuffer Toys
Kong-type food stuffing toys are one of the most popular food activities for dog owners. If you shop sales, you can pick up a variety of stuffing toys. Once you have several, prepare them ahead of time and pop them in the freezer – then just pull one out anytime you need it. Kong, Busy Buddy, SodaPup and West Paw are just a few of the companies that produce a wide variety of stuffing toys.
**Be sure to pick the correct size and type for your dog.
How to Stuff a Stuffer:
If your dog is a beginner, start out by filling the cavity with kibble or dry treats and capping it off with some wet food, squeeze cheese or peanut butter. The wet topper will keep your pup interested until they reach the kibble jackpot.
Once your pup has the hang of it, try filling with kibble that has been soaked in water or broth or just mix the kibble with wet stuff (pumpkin, yogurt, baby food, peanut butter, etc.).
Pack it loosely at first and then start packing it tighter.
Finally, once you have an advanced dog, you are ready to start freezing it. If you are not able to freeze the entire toy, you can freeze things in ice cube trays or small silicone molds and add this to your stuffer toy, along with kibble or ingredients.
What do I use to stuff a stuffer?
You can mix wet and dry ingredients – try peanut butter, apple sauce and banana chunks or yogurt, pumpkin and green beans or soak dry kibble till soggy and mix with cottage cheese and apple chunks.
For more ideas, go to the Kong Company – or simply search the internet for kong stuffing recipes.
DIY Stuffer Toy Enrichment Ideas
Hoof/Horn/Bone – If you are like me, you have a variety of hooves, horns and bones lying around the house. Why not try using them as stuffing toys.
Paper Towel or Toilet Paper Tube – You can put kibble in a tube and either fold the ends over or cap the ends with packing paper. You can also fill the tube with kibble, cap both ends with wet ingredients and then freeze.
Kitchen Items – muffin tins, ice cube trays, old measuring cups, etc.
PVC – Pick up a pvc elbow or tee, stuff it and freeze it – or just smear some peanut butter all around the inside surface.
Try putting a few treats/veggies/fruit into ice cube trays and fill with dilute broth. Freeze and then give a cube to your dog, add one to his bowl, put one in a kong or even float a couple of cubes in a bowl of water or even in a kiddy pool on a hot day.
Put treats/veggies/fruit and broth in a paper cup and stick in a milk bone or carrot that will act as your pupsicle stick. Freeze, unmold and serve.
Same concept, but with an ice cream container. Freeze and unmold in the yard on a hot day. If you have a large enough container, you can even freeze a ball or other toys into the mold.
Licki Mats are silicone squares with ridges that will hold food in the crevices. Smear yogurt, peanut butter or pumpkin in the recesses, stick in some kibble, cut up fruit or veggies and either feed as is or freeze. You can use anything with a textured surface as a licki mat – silicone ice cube trays or candy molds, a grease spatter guard, silicone hot pads, etc.
Dogs are natural foragers and scatter feeding is a perfect way to tap into that instinctive behavior. This is as simple as taking a portion of your dog’s kibble and scattering it in the yard or on the floor and let him sniff it out. Generally, scatter feeding can be done with multiple dogs in the same space. However, be sure that you keep an eye on your dogs’ body language for any signs of tension. It is always safest to start by separating the dogs with something like an x-pen until you are confident that there will be no fighting
Variation on Scatter Feeding: Change things up by putting your dog in another room and then set up a scatter trail. Start near the doorway that your dog will enter and make a trail of treats to lead your dog to another area or room where you have done a scatter or placed a stuffer toy. Another easy idea that you can do while watching television in the evening: Grab your dog’s dinner and toss it a couple of pieces at a time around the room and ask him to “Find It”.
Snuffle mats come in many shapes and sizes and satisfy your dog’s need for foraging and mental stimulation. A standard snuffle mat resembles a rug with very long shag. The idea is to tuck kibble or treats down into the mat and then let your dog snuffle around to find them.
To start out, tuck a few pieces of kibble into the mat and scatter some over the top. Once your pup understands how the game works, you can hide the kibble deep down in the snuffle mat. A lot of dogs will try to disassemble the mat to see if there are any stray treats hiding deep inside. If you have such a pup, be sure to pick up the snuffle mat as soon as your dog has finished the game and put it away for next time.
Variations on the Snuffle Mat: You can turn a basket with holes in it into a snuffle basket. Take a few leftover pieces of fleece, roll a few pieces of kibble or treat up in them and put those in a box. Stuff the rolled up pieces of fleece into a Hol-ee Roller ball.
Make Your Own Snuffle Mat A simple snuffle mat can be constructed in an evening.
Materials: – plastic sink mat – 1-2 fleece blankets or about 1 ½ – 2 yards of fleece – scissors or rotary cutter
Directions: Cut the fleece into strips, about 1″ wide and 8 to 10” long. Thread a strip through each hole in the sink mat and tie it off. Make sure that you have tied a strip through every single hole. Viola! – snuffle mat!
Other DIY Snuffling Activities
Lay out a towel, scatter kibble or treats all over it and then roll it up and let your dog unroll it. To make it more difficult, try tying the roll in a knot, hiding it somewhere in the house or putting it in a box with the flaps closed. You can also scatter treats along one half, fold the towel lengthwise, scatter more treats on top and then roll it up.
Variations on Towel Roll – Use an old pair of jeans and roll treats up in each leg. Spread out a blanket, scatter kibble on top and then either accordion fold the blanket or grab the center and twist to create folds and swirls to hide the treats.
Simply take an empty cardboard box, toss in kibble or a few treats, and turn your dog loose. Once your dog has the hang of this game, fill the box with packing paper, toilet paper or paper towel tubes or tennis balls. You can use kibble or treats, veggies or fruit or even drop in a frozen stuffer toy. To add a bit of a challenge, fold the bottom of a TP tube, drop in a few pieces of kibble, then fold the top to make a little packet. Toss these into the box. For even more of a challenge, close up the flaps of the box. Note: If your dog ingests this type of material, do not attempt this activity if you are not able to supervise your dog. This is a great activity for dogs who enjoy the act of ripping up or dissecting toys. The act of ripping up the box goes a long way in meeting the needs of these dogs.
Do you have a laundry basket or a plastic tub lying around? Toss in some kibble and top with balls. If you have a large enough container, toss in some empty water/soda bottles. Be sure to take of the caps and plastic ring to remove any choking hazards.
Take a set of small plastic cones, dishes or plastic cups and set them up around the room. Place kibble or treats underneath them and let your dog work out how to get to the treats. Once she has the hang of it, try putting kibble under only a few of them, then let her figure out which ones are hiding the kibble.
Put some treats in the cups of a muffin tin and cover them with tennis balls, toys or even silicone muffin liners. Once your dog has the idea, place the whole thing in a basket or a box the just fits the tin. When the dog pushes the balls off the cups, they will keep rolling back over, making it a bit more challenging.
Put some treats in the cups of an egg carton and close up the carton. To make it more challenging, you can tape the carton shut, roll the treats in bits of packing paper or scraps of polar fleece and then put those parcels in the egg carton cups.
Paper Towel and Toilet Paper Tubes
Turn these into little treasure packets by folding one end, dropping in a few pieces of kibble or treats and then folding the other end closed. You can hide these around the house or tuck them into boxes or baskets. If you dog tends to swallow large chunks, start with paper towel tubes for a larger packet and supervise so that you can teach him how to rip open the packet to get to the treasure. Do not use wet, oily or sticky food stuffs like hot dog, cheese or peanut butter as it encourages your dog to eat the cardboard that has that oily, sticky food residue on it.
Purchased Enrichment Toys and Puzzles
There is a huge variety of puzzles for dogs on the market. Many of them are labeled with a rating of how difficult/advanced they are.
There are many different food dispensing toys on the market: Kong Wobbler, Buster Cube, Tug a Jug, Kibble Nibble, Twist a Treat, Kong Gyro … and the list goes on and on. Some are very simple balls with a hole in it. Others have a plastic maze inside or other mechanism to slow the dispensing rate and make the toy more difficult.
If you want to slow down dispensing rate, you can use larger treats/kibble that don’t fall out as easily. Some toys that come apart have enough space to put a ball inside. As the toy tips, the ball will cover the hole occasionally and slow the dispensing of treats.
DIY Food Dispensing Toys
Water Bottle or Milk Jug
Remove the lid and plastic ring (these are choking hazards), wash out the bottle and then drop in a few treats. Your dog will have a great time trying to get the treats out.
Bottle Tipping Activity
You will need a couple of empty milk jugs and a curtain/tension rod. Thread the tension rod through the jug handles and then hang the whole thing in a doorway at a level between your dog’s chest and eye level. Drop some treats in the jugs and show your pup how to tip the jug to get treats to drop. You can also use 2-liter soda bottles. Drill two holes on opposite sides just above the label. Then thread the tension rod through the holes.
Take a long piece of string, yarn or fishing line and string on a few chunks of fruit or veggies, spacing them out along the line. Hang this at your dog’s eye level (e.g., in a doorway, between cabinets or between trees in the yard) and let your pup figure out how to get them off the string. Watch your dog closely to be sure that he does not eat the string!
Pick up an 8 to 12” piece of ~2″ diameter PVC pipe and a couple of caps. Drill a few holes in the pipe, just a bit larger than your kibble/treats. Sand the edges of the holes until there are no rough edges. Put in some treats/kibble, cap the ends and let your dog roll it to release treats. If you want to be a bit fancier, use the pvc pipe, one regular cap, a threaded end and a threaded cap. You can use pvc glue to attach the regular cap on one end of the pipe and the threaded cap on the other. Now you just need to unscrew the end, drop in treats, screw it back on and it is ready to go.
Hide and Seek
Fill multiple toys. Put your dog in another room, hide the toys, and then turn your dog loose. This can work well when you leave the house for the day as long as you use toys that your dog can’t/won’t ingest. If your dog will ingest toys, try doing a snuffle trail that leads them to a frozen kong or other safe toy. You could also hide pieces of kibble or treats inside boxes or other containers and place them around the room.
Sensory Maze or Obstacle Course
On a day when you can’t get out with your dog, try putting together everything you have learned and set up a sensory maze or obstacle course. Use x-pens, boxes or pieces of cardboard to set up a maze or obstacle course for your dog and fill it with enrichment activities and obstacles.
Using Enrichment as a Calming Activity
Food enrichment activities can also be used to calm your dog during stressful situations. Counter conditioning works by associating something scary with something that your dog enjoys. He will learn to like (or at least tolerate) the scary thing since it means something good is about to happen.
Is your dog stressed during a bath? Smear peanut butter on your bathtub surround so you dog can lick it during a bath. They also make a licki bone with suction cups that sticks to walls, floors, etc. Also try lining the tub with a towel before adding water, as some dogs are more scared of the slippery surface than they are of getting a bath. Does your dog hate having her nails clipped? Pull one of those frozen kongs out of the freezer and give them a lick or a treat after every nail. Is your dog afraid of the vet? Bring a licki mat along. A groomer mit with rubber teeth serves as a good portable licki mat.
A mentally enriched dog is a happy (and tired) dog, so Toss that Food Bowl!!
For a million and one other food enrichments ideas, check out of these facebook pages:
Salonen, Milla, et al. “Prevalence, comorbidity and breed differences in canine anxiety in 13,700 Finnish pet dogs”. Nature, vol. 10, article 2962 (2020).
Haug, Lore Il, DVM, MS, DACVB. “Enrichment in dogs and cats”. DVM360 Kansas City Proceedings, August 1, 2009.
Ragen McGowan, et al. “Positive Affect and Learning: Exploring the ‘Eureka Effect’ in dogs”. Animal Cognition, vol. 17: 577-587 (2014).
Herron, M. E., T. M. Kirby-Madden and L. K. Lord. “Effects of Environmental Enrichment on the Behavior of Shelter Dogs”. Journal of the American Veterinary Medical Association, vol. 244 (6): 687-692 (2014)
Bekoff, Marc. “Working for Food Enriches Dogs’ Lives and Break the Boredom”. Psychology Today. May8, 2019.
Bender, Allie and Emily Strong. Canine Enrichment for the Real World. Dogwise Publishing. (2019).