Interest in studying pets and music is growing. The connection is still mostly under-researched, but “dog music” is already being made. Many have heard the old cliché, “Music hath charms to soothe the savage beast,” and it is widely believed to be true. Many of my clients and colleagues swear by music as a tool to reduce anxiety in dogs and cats, whether in the veterinary hospital, the shelter or boarding kennel, or at home when all the humans are away. As always, of course, it is a good idea to take a look at the evidence for even the most obvious and widely held beliefs. To begin with, the cliché is a misquotation. In his play, The Mourning Bride, written in 1697, William Congreve actually wrote, “Musick has Charms to sooth a savage Breast.” The line is spoke by a distraught woman in mourning, and is followed by a complaint that even though inanimate objects can be moved by music, her grief is untouched by it. The common misquotation substitutes “beast” for “breast,” and is often used to suggest music has calming effects on animals. While the provenance of the misquotation is, of course, irrelevant to the claim, it is always interesting to find such a widely known expression of it is, itself, an error. The healing power of music Regardless of how the belief is expressed, the therapeutic benefits of music are assumed by many pet owners and veterinary professionals. Music is cited as a possible therapy for fear and aggression in the most recent issue of the ubiquitous reference book, Blackwell’s Five-Minute veterinary Consult: Canine and Feline.1 Music streaming services and devices designed for companion animals are certified and recommended as a “preferred product” by the popular Fear Free organization. Such endorsements would suggest the verdict is in on the value of music for canine and feline behavior problems. Alas, the reality is, not surprisingly, less definitive. The Standards of Care in Animal Shelters, promulgated by the Association of Shelter Veterinarians, mentions the use of music in the shelter environment, but the discussion reflects the uncertainty in the evidence: “Music has been used to reduce animal stress in a variety of different setting. While anecdotal reports support this finding, little data exist to recommend its use for shelters. Music or other sounds as a form of enrichment need to be considered carefully, particularly if animals have no way to move away or control their exposure. Many animals, including dogs, are able to hear frequencies above what humans can hear. Therefore, if music is introduced, radios or other sound systems should not be placed directly on cages and the volume should not exceed conversational levels.”2 Granted, these guidelines are more than 10 years old, and a new edition is due out later this year. Most of the research evidence regarding the use of music in dogs and cats has been published since these guidelines were issued, so perhaps there is now a case for a stronger recommendation? The most recent assessment of the available evidence does not suggest this is the case.3 This systematic review, published in 2020, comprehensively identifies and critically evaluates the available research on music as a source of auditory enrichment for dogs. Despite acknowledging this use of music has “great potential,” the authors cannot conclude there is strong evidence for meaningful benefits: “Interest in the use of music therapy as a behavioral enrichment tool in veterinary medicine is growing. Indeed, an industry has formed around the development of ‘dog music,’ which has been purposely designed to relax dogs. Despite enthusiastic uptake of the idea, there is little empirical evidence supporting the design of such tools. [Though] animals appear less stressed or anxious when exposed to classical music than to control conditions…This field is relatively under-researched, and more rigorous studies must be conducted before species-specific recommendations can be made. Such studies must reflect individuals’ and species’ preferences for different genres and songs, taking care to avoid habituation.”3 Details More studies are needed, but it appears music can soothe animals. Available studies are generally small, short-term, and applicable only to dogs in kennels or veterinary settings, not the home. They consistently show behavioral effects of music, and there is inconsistent and more limited evidence for measurable physiologic effects, such as changes in heart rate variability or cortisol levels. What they do not show is meaningful impact in the prevention or amelioration of behavioral pathologies, improved health outcomes, improved quality of the human-animal bond, or reductions in relinquishment or euthanasia attributable to behavior problems. Admittedly, these represent a high bar for the impact of music as an enrichment tool, but these are the kinds of outcomes that matter to dogs and their owners, and if these are not affected then the value of musical enrichment is doubtful. As is often the case, one notable challenge in evaluating the research evidence is the heterogeneity in the treatment employed and the outcomes measured. While general labels, such as “classical music” or “rock music” are employed, these obviously represent broad categories with significant variation in the individual pieces of music included. Such terminology also assumes human aesthetic categories will be relevant to dogs, and this is a doubtful assumption given the uniqueness of the human species in the production and appreciation of music. More specific focus on pitch, tempo, volume, timbre, and other variables might make the research data more useful. It is also often assumed in studies of music enrichment that an increase in “calm” behavior, such as lying down, and a decrease in movement or vocalization represents a positive effect. However, don’t humans use music to raise our level of arousal and activity as often as to reduce it? If music can benefit us by psyching us up for a workout or driving us onto the dance floor with our friends as much as to relax after work, why would this be a less valuable application for our pets? Such anthropomorphic assumptions complicate the investigation and use of music as a form of enrichment or behavior therapy. Like any intervention, music has to be considered in terms of its risks as well as its benefits. There is relatively little evidence looking at potential harms, largely because of the assumption embedded in the design of many studies that music is likely to be benign. Having been trapped and forced to endure music played by others that I found excessively loud or inherently unpleasant, I am inclined to wonder if we might not be just as likely to be torturing our hospitalized patients or our pets left home alone by playing music at them. This aspect of the issue deserves more thorough and explicit attention. Regular readers will not be surprised to hear there is considerably less evidence regarding the impact of music on the behavior of cats than on dogs. A few recent studies have tentatively suggested music designed for cats, and possibly that generic category of “classical music,” may have some impact on behavioral manifestations of stress in cats in a veterinary context.4-6 As with dogs, however, the research is limited by small studies, lack of replication, mixed and often statistically insignificant results, and other factors precluding any confident conclusions about the benefits of various kinds of music enrichment for cats even in the veterinary setting, much less in the home. Bottom line Music is widely viewed as beneficial for dogs and cats in kennels, shelters, and veterinary settings. Use of music, particularly so-called “classical music” (generally characterized by lower tempo and volume than other genres), is believed to be calming and to reduce stress and anxiety. However, the available research is sparse and has significant limitations preventing any confident conclusions. Ultimately, the potential benefits, and to an even greater degree the potential harms, of music as auditory enrichment are under researched, and the common use of this in the home and institutional settings is based more on anecdote and assumption than on reliable evidence of meaningful animal health and welfare effects. Brennen McKenzie, MA, MSc, VMD, cVMA, discovered evidence-based veterinary medicine after attending the University of Pennsylvania School of Veterinary Medicine and working as a small animal general practice veterinarian. He has served as president of the Evidence-Based Veterinary Medicine Association and reaches out to the public through his SkeptVet blog, the Science-Based Medicine blog, and more. He is certified in medical acupuncture for veterinarians. Columnists’ opinions do not necessarily reflect those of Veterinary Practice News. References Tilley L, Smith FJ, Sleeper M, Brainard B. Blackwell’s Five-Minute Veterinary Consult. Canine and Feline. 7th ed. (Tilley L, Smith FJ, Sleeper M, Brainard B, eds.). Ames, Iowa, USA: Wiley-Blackwell Newbury S, Blinn MK, Bushby PA, et al. Guidelines for Standards of Care in Animal Shelters Association of Shelter Veterinarians TM.; 2010. https://www.sheltervet.org/assets/docs/shelter-standards-oct2011-wforward.pdf. Accessed March 18, 2022. Lindig AM, McGreevy PD, Crean AJ. Musical Dogs: A Review of the Influence of Auditory Enrichment on Canine Health and Behavior. Animals. 2020;10(1):127. doi:10.3390/ani10010127 Paz JE, da Costa FV, Nunes LN, Monteiro ER, Jung J. Evaluation of music therapy to reduce stress in hospitalized cats. J Feline Med Surg. December 2021:1098612X2110664. doi:10.1177/1098612X211066484 Hampton A, Ford A, Cox RE, Liu C-C, Koh R. Effects of music on behavior and physiological stress response of domestic cats in a veterinary clinic. J Feline Med Surg. 2020;22(2):122-128. doi:10.1177/1098612X19828131 Snowdon CT, Teie D, Savage M. Cats prefer species-appropriate music. Appl Anim Behav Sci. 2015;166:106-111. doi:10.1016/J.APPLANIM.2015.02.012
