The very latest study on dog-human relationships has revealed a correlation between dogs' cardiac responses to positive interactions and those of their human guardians

Sydney: In the wild, dogs spend a lot of their time chewing on bones, carcasses, sticks and kernels. For example, Australian dingoes can feed for up to 108 minutes in a single session.

But most domestic dogs chew far less than their free-roaming counterparts. This is largely because of the introduction of easy-to-eat, processed pet foods such as kibble, which now comprises the majority of domestic dogs’ diet. This is a problem because although chewing carries some risks, overall it has significant benefits for dogs.

As our new review, published in Frontiers in Veterinary Science, demonstrates, it enriches the physical, psychological and emotional health of dogs in many interconnected ways.

1. Food acquisition and nourishment

Dogs chew primarily to nourish themselves. Their large canine, premolar and molar teeth and wide gape help them to capture and dismember prey. Chewing whole carcasses provides them access to marrow, fibre and minerals that would otherwise be inaccessible.

When they are not chowing down on body parts, free-ranging dogs forage on nuts, berries, and insects – a portion of which are also hidden in kernels, shells or exoskeletons and require chewing.

2. Clean teeth and oral hygiene

Dental disease is one of the most common health issues in companion and kennelled dogs. It is more common in smaller and older dogs. The abrasive action of chewing on hard and fibrous materials helps to remove and prevent the formation of plaque. This reduces bad breath, gum disease, tooth loss and therefore the requirement for dental procedures at the vet clinic.

Of course, dogs with existing dental issues might find it impossible to chew. And it is recognised that some dental fractures may arise from chewing.

3. Gastrointestinal health

Chewing between meals can help facilitate digestion in all mammals. It can also prevent stomach inflammation and stimulate peristalsis (waves of contractions) in the gastrointestinal tract. This helps maintain regular bowel movements and stool consistency.

4. Healthy microbiome

The action of chewing promotes resident bugs that comprise a healthy microbiome and reduces harmful microbes, both in the oral cavity and in the lower intestine. The microbes of the microbiome work for their own survival and also for that of their dog host, for whom they help maintain healthy oral hygiene and gut health.

5. Stress management

Chewing stimulates the rest-and-digest elements of a dog’s life and can reduce acute stress. This gives dogs a potential mechanism to manage some of the challenges of both boredom and over-arousal. In this way, providing long-lasting chewables can help to alleviate anxiety associated with challenging situations such as being home alone.

6. Bone density

Stress is common to all mammals. It causes a release of cortisol, a hormone that can reduce bone density and, over time, lead to osteoporosis. Because chewing makes dogs less stressed, it can help to prevent some forms of osteoporosis by reducing corticosteroid concentrations in the blood.

7. Performance and focus

Dogs can moderate their own arousal levels if they have the opportunity to chew. This appears to be bidirectional in that chewing can be stimulating for a bored dog or calming for an unsettled dog.

As such, chewing may be a unique means of bringing dogs into the Goldilocks zone of arousal, also known as “eustress”. This zone improves a dog’s ability to focus, learn and perform complex tasks.

8. Ageing well

Dogs are living longer than they have in the past. Because of this, more are experiencing cognitive decline. Research has shown that in other mammals, such as humans and rodents, chewing can protect cognitive function.

For dogs already suffering some loss of cognitive function, chewing, with its variety and manipulative challenges, may be a valuable management tool to help sustain quality of life.

9. Positive welfare

The pet industry supplies myriad chewable products ranging from toys, dried or fresh animal products and commercially made chews. They are meeting the market populated by carers who’ve noticed their dogs relish chewing.

Dogs usually become enlivened when offered chews, seeking them out and playing with them. Some even find a chew so highly valuable that they risk breaking bonds with dog or human family members by exhibiting resource-guarding behaviours.

When we fail to provide chewables, dogs will instead select other less appropriate articles to serve their purpose. In the smorgasbord of potential targets in our homes, leather shoes are often toward the top of the menu.

10. Happy dogs make happy humans

The very latest study on dog-human relationships has revealed a correlation between dogs’ cardiac responses to positive interactions and those of their human guardians.

Although this study focussed on co-operative breed types, such as herding dogs, known to be highly responsive to humans, it demonstrated that cardiac activity of dogs and their owners mirrored each other. It also indicated cross-species connections comparable to those found in attachment relationships between humans.

So, providing your dog with a way to de-stress can have the same benefits for your own emotional and physiological state. Incorporating chewing into the daily lives of our dogs may be one simple yet important way to ensure they are living happy and healthy lives. Note that chewing ability is individual and advice on the type of chew and its suitability for your dog should be sought from your veterinarian.