When I go to meet client dogs, I usually cause their humans a degree of disgust by producing, at some point in the consultation, a dried animal part. Pizzles (dried bulls’ penises), goat ears, cows’ hooves, and ostrich tendons are amongst my usual arsenal.
You might wonder what possesses me to show up at a stranger’s home or workplace equipped with such things. Well, the simple answer is that dogs need to chew. Chewing forms part of the dog’s ethogram (their normal, species-specific behaviours), and provides many benefits to their
welfare.
Chief amongst these is perhaps the fact that chewing helps dogs (and other mammals) cope with stress. Chronic stress is detrimental to both physical and mental health, and will eventually lead to disease, and very often to behavioural problems in dogs. Research done by Kin-ya Kubo et al. has found that chewing is an effective means of coping with stress, most likely due to the changes it causes in the in the activity of the HPA axis (the hypothalmic-pituitary-adrenal axis, through which the main neuro-endocrine response to stress is activated) as well as to the autonomic nervous system. It was found that under stressful conditions, chewing reduced increases in hormones such as cortisol and adrenaline. A 2014 study showed that maternal chewing during times of stress in pregnancy reduced cortisol production and prevented prenatal stress-induced learning deficits in adult off-spring.
Of particular interest at this time of year, with Halloween fast approaching, is the fact that astudy in humans found that chewing gum while subjected to loud noises inhibited the propagation of stress-related information in the brain. The way the human brain works and the way the dog’s brain works is very similar in terms of stress response, so it stands to reason that the same may be true of our dogs when it comes to chewing and loud noises such as fireworks.
Of course, chewing is not just for dogs exhibiting signs of stress. It offers other benefits too. It releases feel-good endorphins in the brain, fights boredom, helps keep the teeth and gums healthy and is a good workout for the paw muscles. From a health perspective, a change in chewing behaviour can help us identify problems with our dogs’ oral health or paws. If a dog who has always loved to chew is suddenly turning his nose up at chews, it’s a good indicator for a vet’s visit. For young dogs, who are wont to find less appropriate things to chew, providing food-based chews can protect your chair legs, skirting boards, and even your fingers!
So, presuming I’ve convinced you that chewing should be on the menu of daily activities for all of our dogs, the next question is what sort of thing should our dogs be chewing? My general advice is that:
- The item should be food-based. Offering toys to chew will often lead to playing and excitement, rather than the sort of calm, rest-and-digest activity that you want;
- Natural, digestible items are a safer bet than the highly processed, bleached, coloured and glued raw hide that you often find in pet shops;
- Rubber chews are often not that appealing for dogs- the natural chews will smell and taste more appetising!
References:
Kubo KY, Iinuma M, Chen H. Mastication as a Stress-Coping Behavior. Biomed Res Int. 2015;2015:876409. doi:10.1155/2015/876409
Azuma K, Zhou Q, Niwa M, Kubo KY. Association between Mastication, the Hippocampus, and the HPA Axis: A Comprehensive Review. Int J Mol Sci. 2017;18(8):1687. Published 2017 Aug 3. doi:10.3390/ijms18081687
Yu H., Chen X., Liu J., Zhou X. Gum chewing inhibits the sensory processing and the propagation of stress-related information in a brain network. PLoS ONE. 2013;8(4)
Onishi M., Iinuma M., Tamura Y., Kubo K.-Y. Learning deficits and suppression of the cell proliferation in the hippocampal dentate gyrus of offspring are attenuated by maternal chewing during prenatal stress. Neuroscience Letters. 2014;560:77–80. doi: 10.1016/j.neulet.2013.12.013