I was more than thrilled last week to find a science-based review of shelter stress in dogs. Not only is the article a fantastic review of research in this area for the last decade or so but, it turns out the author, Mike Hennessy, (see reference below) is practically down the road from me (Hennessy is a researcher at Wright State). I recently contacted Mike and he invited me to come observe the data collection for a study he is conducting with a nearby animal shelter. So, I'll have the opportunity to watch a skilled applied researcher and his graduate student work with shelter dogs. I'll be sure to post an update on the visit so please stay tuned. In the meantime, I wanted to highlight just a fraction of the information in Hennessy's recent article.
First, Hennessy's article is a review article-which means that it doesn't report the results of a single study or experiment but provides a fairly comprehensive review of numerous studies on a particular topic. In my experience, review articles can be a highly efficient way for an interested readers to get a handle on the work done around a particular area of research.
So, now on to some of the good stuff contained in the article...Hennessy is interested in the role of dogs' primary stress-response system which is the hypothalamic-pituitary-adrenal or HPA axis. Within the HPA axis, cortisol is but one substance that is secreted when dogs experience stress. Do shelter dogs experience stress? You betcha!!! Noise, separation from prior owner, confinement, schedules which are often unpredictable, etc. come to mind but there are others. Thus, looking at dogs' cortisol levels can provide insights to what particular features of the shelter environment are most likely to induce stress and whether interventions are successful in reducing dogs' stress. Cortisol levels can be assessed through various means with plasma and salivary typically being viewed as providing the most reliable measures of acute stress whereas urine, feces and hair are indicative of stress of a more prolonged nature. Below I'll highlight three factors that have been identified as influencing stress levels in shelter dogs:
History of the dog: It seems that one important difference in shelter dogs' cortisol levels is their history prior to arriving at the shelter. Specifically, the shelter experience appears to be less stressful for dogs that are found as strays and those dogs that are returned to the shelter as compared to dogs surrendered from their homes and who have no prior experience being in a shelter. I know that this conclusion fits with my own observations. That is, the dogs, which seem to be the most panicked when first arriving at the shelter are those who are owner surrenders. However, there does seem to be the occasional dog that is an owner surrender that appears to settle without much apparent stress. Perhaps these dogs are relieved to be free of a neglectful or cruel owner. What about your observations?
Type of Human Interaction: Hennessy (1997; 1998) was involved in several interesting studies that examined at the specific types of interactions that shelter dogs had with people. An initial investigation revealed that shelter dogs that interacted with men actually experienced increased cortisol levels whereas dogs interacting with women did not experience this spike in cortisol levels. However, and this important, it turned out that the women participating in the study were more experienced dog handlers as compared the men. Based on the above, a second study was conducted in which women taught the men handlers as series of techniques that they used (i.e., slow, deep massage accompanied by soothing speech). Once the men were "trained up" it turned out that differences between men and women in terms of the dogs' cortisol responses were erased. These findings were found to hold true for both puppies and adult dogs.
I think the findings from the above studies are fascinating. In my opinion, these findings underscore the need for shelters to provide mindful instruction and training for volunteers and staff who are interacting with shelter dogs. Helping individuals who work with dogs understand how their speech and movement influence dogs’ stress levels has been validated by science and can no longer be considered something to be taken for granted.
Control and Predictability: Hennessy notes that a finding that has been consistent across numerous studies and various species is that when individuals are exposed to an stressor (e.g., noise) they perceive to be unpredictable and out of their control, there is an increase in stress levels.
For those of you who are familiar with basic psychology/ stress principles, this conclusion might sound like old hat. Nonetheless, I think that the practical implications of these findings are still compelling. For example, many animal shelters rely heavily on volunteers to provide interaction with shelter dogs; however, it can be a real logistical struggle to ensure that the way volunteers are interacting with shelter dogs are predictable. Consider for example, the simple act of a walking harness being put on a dog by a person unfamiliar to the dog. For some dogs this procedure might be stressful-particularly if the dog has not worn a harness before. It would be suggested that those who are harnessing the dog do so in a relatively uniform way (with respect to how they approach the dog, how the harness is placed over the dogs head, etc.) so as to minimize the stress a shelter dog experiences. Additionally, having predictable routines for feeding, exercising, etc. would be useful from an animal welfare perspective.
Meanwhile on the home front, our 15.5 year old dog Sophie continues to delight and inspire me. She has been going for physical therapy and acupuncture treatments for the past month so that we can keep Sophie's functioning level as high as possible for as long as possible. The picture below shows Sophie during an acupuncture treatment (mainly for arthritis in her spine). I've heard that many dogs will relax and sleep during their acupuncture treatments; Sophie does not follow this philosophy...she definitely has FOMO; she tends to walk around the room and check for treats that may have been overlooked by other dogs.
(Reference: Hennessy, M. Using hypothalamic-pituitary-adrenal measures for assessing and reducing the stress of dogs in shelters: A review [in press], Applied Animal Behavior Science.)