Viewpoint articles represent the opinions of the authors and do not represent AVMA endorsement of such statements.
Introduction
For any animal, understanding life histories is essential to understanding how to attain the highest quality of life appropriate to different stages of aging. At a minimum, knowing the average life expectancy for a given species enables us to estimate when different life stages might start and end. Such knowledge can also help inform when we might expect certain pathologies to emerge and assess overall health at the population level. This information is critical when it comes to maintaining health and well-being and, ideally, preventing or ameliorating illness and deterioration of quality of life over the lifespan. This understanding is also important for guiding those involved in end-of-life (EOL) decisions and care.
Despite major advances in veterinary science across the board, and in accurately interpreting age-related DNA methylation changes via molecular clocks in humans and other mammals (including dogs),1,2 there is a lack of concurrence surrounding the basic aspect of our knowledge about dogs that is lifespan. In recent years, some have argued that the dog lifespan is shortening, especially in some specific breeds,3 and despite the sparseness of evidence for the conjecture, the suggestion has undoubtedly influenced human decision-making regarding care of companion animals.4 For example, depending on available resources, an owner of a 3-year-old dog might opt for a more extreme medical intervention should the need arise than if the dog were nearing what was understood to be its twilight.
Conversely, advances in preventive veterinary care and disease treatment and management, more widespread access to and use of veterinary care, and shifts in cultural attitudes toward family dogs (eg, more dogs living in households as opposed to being free-ranging, popularity of pet health insurance) might reasonably contribute to a longer average dog life expectancy, if anything.5–10 Indeed, some suggest that an increase in incidence of canine cancers can be attributed to an overall longer lifespan,11 in addition to the chemical exposures dogs share with humans.12–14
In addition to impacting canine care and EOL decisions, in order for dogs to serve as an effective translational model for human disease outcomes, biomarkers, and aging, this knowledge gap regarding the average dog lifespan—not only life expectancies for specific breeds or categories of dogs—must be remedied. We suggest here a path toward more accurate discovery would be for the veterinary community at large—including researchers, animal care workers, veterinary staff, insurance companies, shelter workers, and even pet owners—to adopt a more consistent practice of reporting canine mortality.
The Challenge of Inconsistent Dog Mortality Data Gathering and Reporting
The contrast in reports regarding dog lifespan or life expectancy is primarily due to significant gaps and inconsistencies in the way that mortality data for domestic household dogs are recorded and reported and the near complete absence of mortality data on domestic free-ranging dogs (but note Demeli and Urfer15). Existing life expectancy datasets primarily include geographic- or breed-specific cohorts.16–23 Many other studies focus on specific causes of death, risk factors, and/or rates of death in specific breeds.17,24–29 While assessments such as these should not be discounted, as they are important for early detection of disease and for guiding lines of inquiry in research, the insight they offer on overall lifespan averages is limited.
Additionally, it is difficult to compare available data between studies, as they rely on varying sources such as cemetery records, electronic medical records (EMRs) from private practices, breed registries, and insurance records. Different methodological approaches also introduce source-specific bias (eg, certain breeds may potentially have higher representation ensured and breed registry data, crossbreds may be more represented in rehoming data, there are issues with age-limited insurance policies, etc), and existing datasets may include missing or incorrect data (eg, cause of death and/or age at death unknown or unrecorded; euthanasia cases across ages, when counted, skew averages; nondeceased cohort members of longitudinal studies are not considered; etc).16
In studies not limited strictly to mortality data, the varied use of lifespan (single number) versus life expectancy reporting among studies is problematic, as some look at maximum time of survival for 1 or more individuals in the study population,22,30 while others use actuarial life tables calculating the probability of death starting from age 0 or 1 and represent the average lifespan of the study population.16,19,23,31 Likewise, the number of observed years for each cohort is not consistent from study to study, and some derive estimates from the total cohort while others use death data from the current year in which analyses were conducted.
To this point, Urfer et al20—who report a median dog lifespan of 15.4 years—rightly note that canine lifespan studied in the context of mortality data is limited to deceased animals and fails to include individuals from the same birth year/cohort that were living at the time of data collection. This truncation can lead to an underestimation of lifespan, or right-censoring. There are methods to help remedy these issues in longitudinal studies with multiple data points, such as Kaplan-Meier analysis and Cox regression in determining a median survival time, as used by Urfer et al.20 However, inconsistent use of such methods, as noted above, makes them unhelpful when attempting to compare the available datasets from various authors.
In most instances, reports calculate average lifespan for all dogs in the dataset but also for gonadectomized versus intact dogs (reporting longer lifespans for gonadectomized with caveats regarding cause of death) and specific breeds versus “hybrids” versus “mongrels” or mixed breeds, with most reporting that purebred dogs have a shorter average lifespan compared to hybrid/mixed-breed dogs and to the whole cohort. Given the likely inaccuracies in recorded breed for those datasets, especially among cemetery records and EMRs with owner-reported breeds of adopted dogs (ie, not self-bred, obtained directly from a breeder, or registered with a kennel club), analyses primarily concerned with comparing group mortality rates should be interpreted cautiously. Teng et al23 also suggest that differences in popularity of specific breeds over time may skew data availability (that is, there may be overrepresentation of a particular breed in the population based on demand) and therefore lifespan estimates.
Furthermore, historically in some cases, studies have excluded dogs that died from specific conditions and/or discriminated between those dogs whose mortality was attributed to “natural causes” versus euthanasia in calculating lifespan estimates. For example, Patronak et al30 excluded dogs that died prematurely from “trauma/poison,” which is still a tangible and potential cause of death (and indeed contributed to the deaths of some in the study cohort) and thus should have been included so as to not skew the lifespan estimate for that dataset. Euthanasia is a leading cause of death for domestic dogs32,33—regardless of being prompted by illness, age, behavioral issues, or otherwise—and should only be distinguished as a subcohort in calculating lifespan estimates for the purposes of addressing and remedying dog welfare concerns (eg, overcrowded shelters, owner surrenders, etc).
Though Problematic, Canine Lifespan Data Do Appear to Point in One Direction
Though clearly problematic, available dog lifespan data do span a relatively substantial period of time, beginning in at least the early 1980s and continuing to the present, and data collection, if not consistent, has at least occurred at relatively consistent intervals during these years. We do not believe a systematic review of these data would be prudent at this time given the aforementioned limitations and variation in methodologies.34 However, we do think that existing studies can be used to make a cursory judgment (at the very least more accurate than what has been reported in the popular press) of whether there has been an overall increase or decrease in dog life expectancy over the last 40 years. With this information at hand to be used with reserve as a relative baseline, proceeding forward with a more robust plan for dog mortality data collection and management will do wonders in the effort to resolve the standing debate.
According to a dozen large cohort studies (11 published findings and 1 open access dataset) with mortality records collected from 1981 to 2023,16,19–23,30–33,35,36 reported dog lifespan ranged from 8.5 to 15.4 years, with the majority of more recent studies reporting longer lifespans (Supplementary Table S1). These studies include dog mortality data available from a variety of sources, including EMRs, animal cemetery records, veterinary insurance records, kennel club registries, and a longitudinal study.
Among these data, the lowest reported median life expectancy for mixed breeds was 8.5 years, reported by Patronek et al30 using data from 1980 to 1990. For all breeds and mixed breeds combined, the lowest reported median lifespan was 8.6 years, as reported in the earliest study by Hayashidani et al.19 The highest median life expectancy for all breeds was 15.4 years, as reported by Urfer et al.20 For all studies including data collected in 1997 or later, median reported life expectancy for all breeds was 10 years or older. Thus, it would appear that there is little evidence that the lifespan of domestic dogs has decreased over the last 40 years, and in fact the opposite seems to be true.
Recommendations
While flawed, available data suggest that the lifespan of the domestic dog has not declined over the last 40 years, nor do we know it to be in a current state of decline. However, dogs’ lifespans may be affected more than they have been previously by new and/or different risk factors, especially those related to the shared human-dog exposome. The inconsistencies in historic reporting of mortality in dogs make a fully accurate determination of the average dog lifespan difficult to ascertain and as a result also impact our ability to assess the urgency of responding to such risk factors.
We therefore recommend the adoption of a comprehensive, standardized method for reporting and recording dog mortality so that more accurate reporting of dogs’ lifespans can be made moving forward. Private practice veterinarians, veterinary research groups, animal shelters and rescue organizations, animal control agencies, veterinary insurance companies, and pet cemeteries should implement a dog mortality record for all dogs under their care or for which they are responsible at EOL. At a minimum, the dog mortality record should include the following: date and place of death, age at death (approximate or known), sex and neuter status, reason or cause of death, comorbidities present at the time of death, weight, breed(s), and whether the dog was owned or free-living. Dog mortality record information can be recorded in individual databases or, ideally, uploaded to a shared, publicly accessible database. An example of a first step in this direction has been introduced by the Dog Aging Project’s End of Life Survey,37 a standard survey instrument deployed to all of the project’s participants who report the death of their dog. Of course, we recognize that establishing a centralized repository for data and having staff available to update and compute data will be logistical hurdles, and the support from large institutions will be critical for success. For example, the US military’s Joint Pathology Center has a system for issuing death certificates for military service dogs, which could be a helpful resource.
Once data collection has been standardized, efforts can be made to then standardize the methods used by veterinary researchers to conduct analyses aimed at reporting lifespan information. Furthermore, regarding such analyses, given the genetic basis for many behaviors, pathologies, and physical predispositions, what would be more useful from a veterinary perspective than the common practice of comparing purebred to nonpurebred dogs in large cohort studies would be for future research to identify and update differences in life expectancy and relevant causes of death among various breeds (where known with certainty), age groups, sizes, and lifestyles (ie, working, companion, etc), such as in Fleming et al.27
A realistic perspective on aging and mortality in dogs has crucial implications for their care and treatment over the course of and at different stages of life. Understanding a dog’s expected lifespan is also not inconsequential to mental and emotional well-being of the human companions who form close bonds with the animals and are likely to experience grief at their passing. It is likewise essential to tracking the potential progression of various zoonotic diseases, tracking whether future interventions or noncontrolled factors might impact overall lifespan, and for validating the use of dogs as a translational model for understanding human disease, aging, and quality of life.
Supplementary Materials
Supplementary materials are posted online at the journal website: avmajournals.avma.org.
Acknowledgments
The Dog Aging Project Consortium comprises Dr. Ruple and the following authors of this report: Joshua M. Akey, PhD (Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ); Brooke Benton, MPH (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA); Elhanan Borenstein, PhD (Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Blavatnik School of Computer Science, Tel Aviv University, Tel Aviv, Israel; and Santa Fe Institute, Santa Fe, NM); Marta G. Castelhano, DVM, MVSc (Cornell Veterinary Biobank, College of Veterinary Medicine, Cornell University, Ithaca, NY); Amanda E. Coleman, DVM, DACVIM (Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA); Kate E. Creevy, MS, DVM, DACVIM (Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX); Kyle Crowder, PhD (Department of Sociology, University of Washington, Seattle, WA; and Center for Studies in Demography and Ecology, University of Washington, Seattle, WA); Matthew D. Dunbar, PhD (Center for Studies in Demography and Ecology, University of Washington, Seattle, WA); Virginia R. Fajt, PhD, DVM, DACVCP (Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX); Annette L. Fitzpatrick, PhD (Department of Family Medicine, University of Washington, Seattle, WA; Department of Epidemiology, University of Washington, Seattle, WA; and Department of Global Health, University of Washington, Seattle, WA); Unity Jefrey, PhD, VetMB, DACVP (Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX); Erica C. Jonlin, PhD (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA; and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA); Matt Kaeberlein, PhD (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA); Elinor K. Karlsson, PhD (Bioinformatics and Integrative Biology, Chan Medical School, University of Massachusetts, Worcester, MA; and Broad Institute of MIT and Harvard, Cambridge, MA); Jonathan M. Levine, DVM, DACVIM (Department of Small Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX); Jing Ma, PhD (Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA); Robyn L. McClelland, PhD (Department of Biostatistics, University of Washington, Seattle, WA); Daniel E. L. Promislow, PhD (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA; and Department of Biology, University of Washington, Seattle, WA); Stephen M. Schwartz, PhD (Department of Epidemiology, University of Washington, Seattle, WA; and Epidemiology Program, Fred Hutchinson Cancer Research Center, Seattle, WA); Sandi Shrager, MSW (Department of Biostatistics, Collaborative Health Studies Coordinating Center, University of Washington, Seattle, WA); Noah Snyder-Mackler, PhD (School of Life Sciences, Arizona State University, Tempe, AZ; Center for Evolution and Medicine, Arizona State University, Tempe, AZ; and School for Human Evolution and Social Change, Arizona State University, Tempe, AZ); Silvan R. Urfer, DMV (Department of Laboratory Medicine and Pathology, School of Medicine, University of Washington, Seattle, WA); Benjamin S. Wilfond, MD (Treuman Katz Center for Pediatric Bioethics, Seattle Children’s Research Institute, Seattle, WA; and Division of Bioethics and Palliative Care, Department of Pediatrics, School of Medicine, University of Washington, Seattle, WA).
Disclosures
The authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.
Funding
The Dog Aging Project is supported by U19 grant AG057377 from the National Institute on Aging, a part of the NIH, and by additional grants and private donations.
ORCID
C. Sexton https://orcid.org/0000-0003-0174-7459
References
- 1.↑
Horvath S, Lu AT, Haghani A, et al. DNA methylation clocks for dogs and humans. Proc Natl Acad Sci U S A. 2022;119(21):e2120887119. doi:10.1073/pnas.2120887119
- 2.↑
Jiménez AG. A revisiting of “the hallmarks of aging” in domestic dogs: current status of the literature. Geroscience. 2024;46(1):241-255. doi:10.1007/s11357-023-00911-5
- 3.↑
Manning S. Study aims to uncover why cancer plagues Golden Retrievers. AP News. Published May 6, 2015. Accessed April 18, 2024. https://apnews.com/domestic-news-domestic-news-general-news-pets-1c38b130dd69481c932bb287b907e07b
- 4.↑
McCune S, Promislow D. Healthy, active aging for people and dogs. Front Vet Sci. 2021;8:655191. doi:10.3389/fvets.2021.655191
- 5.↑
Park RM, Gruen ME, Royal K. Association between dog owner demographics and decision to seek veterinary care. Vet Sci. 2021;8(1):7. doi:10.3390/vetsci8010007
- 6.
Smith SM, George Z, Duncan CG, Frey DM. Opportunities for expanding access to veterinary care: lessons from COVID-19. Front Vet Sci. 2022;9:804794. doi:10.3389/fvets.2022.804794
- 7.
LaVallee E, Mueller MK, McCobb E. A systematic review of the literature addressing veterinary care for underserved communities. J Appl Anim Welf Sci. 2017;20(4):381-394. doi:10.1080/10888705.2017.1337515
- 8.
Bir C, Ortez M, Olynk Widmar NJ, Wolf CA, Hansen C, Ouedraogo FB. Familiarity and use of veterinary services by US resident dog and cat owners. Animals (Basel). 2020;10(3):483. doi:10.3390/ani10030483
- 9.
Brockman BK, Taylor VA, Brockman CM. The price of unconditional love: consumer decision making for high-dollar veterinary care. J Bus Res. 2008;61(5):397-405. doi:10.1016/j.jbusres.2006.09.033
- 10.↑
Williams A, Williams B, Hansen CR, Coble KH. The impact of pet health insurance on dog owners’ spending for veterinary services. Animals (Basel). 2020;10(7):1162. doi:10.3390/ani10071162
- 11.↑
Sarver AL, Makielski KM, DePauw TA, Schulte AJ, Modiano JF. Increased risk of cancer in dogs and humans: a consequence of recent extension of lifespan beyond evolutionarily-determined limitations? Aging Cancer. 2022;3(1):3-19. doi:10.1002/aac2.12046
- 12.↑
Wise CF, Hammel SC, Herkert NJ, et al. Comparative assessment of pesticide exposures in domestic dogs and their owners using silicone passive samplers and biomonitoring. Environ Sci Technol. 2022;56(2):1149-1161. doi:10.1021/acs.est.1c06819
- 13.
Craun K, Luethcke KR, Shafer M, et al. Environmental chemical exposures in the urine of dogs and people sharing the same households. J Clin Transl Sci. 2020;5(1):e54. doi:10.1017/cts.2020.548
- 14.↑
Wise CF, Hammel SC, Herkert N, et al. Comparative exposure assessment using silicone passive samplers indicates that domestic dogs are sentinels to support human health research. Environ Sci Technol. 2020;54(12):7409-7419. doi:10.1021/acs.est.9b06605
- 15.↑
Demeli A, Urfer SR. Is free-roaming a key factor determining lifespan? An epidemiological study on the life expectancy of Turkish companion dogs. Res Vet Sci. 2023;162:104953. doi:10.1016/j.rvsc.2023.104953
- 16.↑
Montoya M, Morrison JA, Arrignon F, et al. Life expectancy tables for dogs and cats derived from clinical data. Front Vet Sci. 2023;10:1082102. doi:10.3389/fvets.2023.1082102
- 17.↑
Bonnett BN, Egenvall A, Olson P, Hedhammar A. Mortality in insured Swedish dogs: rates and causes of death in various breeds. Vet Rec. 1997;141(2):40-44. doi:10.1136/vr.141.2.40
- 18.
Bonnett BN, Egenvall A, Hedhammar A, Olson P. Mortality in over 350,000 insured Swedish dogs from 1995-2000: I. Breed-, gender-, age- and cause-specific rates. Acta Vet Scand. 2005;46(3):105-120. doi:10.1186/1751-0147-46-105
- 19.↑
Hayashidani H, Omi Y, Ogawa M, Fukutomi K. Epidemiological studies on the expectation of life for dogs computed from animal cemetery records. Nippon Juigaku Zasshi. 1988;50(5):1003-1008. doi:10.1292/jvms1939.50.1003
- 20.↑
Urfer SR, Kaeberlein M, Promislow DEL, Creevy KE. Lifespan of companion dogs seen in three independent primary care veterinary clinics in the United States. Canine Med Genet. 2020;7(1):7. doi:10.1186/s40575-020-00086-8
- 21.
Lewis TW, Wiles BM, Llewellyn-Zaidi AM, Evans KM, O’Neill DG. Longevity and mortality in Kennel Club registered dog breeds in the UK in 2014. Canine Genet Epidemiol. 2018;5(1):10. doi:10.1186/s40575-018-0066-8
- 22.↑
O’Neill DG, Church DB, McGreevy PD, Thomson PC, Brodbelt DC. Longevity and mortality of owned dogs in England. Vet J. 2013;198(3):638-643. doi:10.1016/j.tvjl.2013.09.020
- 23.↑
Teng KTY, Brodbelt DC, Pegram C, Church DB, O’Neill DG. Life tables of annual life expectancy and mortality for companion dogs in the United Kingdom. Sci Rep. 2022;12(1):6415. doi:10.1038/s41598-022-10341-6
- 24.↑
Dettori A, Ferroni L, Felici A, Scoccia E, Maresca C. Canine mortality in Umbria region (central Italy): a population-based analysis. Vet Res Commun. 2023;47(4):2301-2306. doi:10.1007/s11259-023-10146-6
- 25.
Yordy J, Kraus C, Hayward JJ, et al. Body size, inbreeding, and lifespan in domestic dogs. Conserv Genet. 2020;21(1):137-148. doi:10.1007/s10592-019-01240-x
- 26.
Hoffman JM, Creevy KE, Franks A, O’Neill DG, Promislow DEL. The companion dog as a model for human aging and mortality. Aging Cell. 2018;17(3):e12737. doi:10.1111/acel.12737
- 27.↑
Fleming JM, Creevy KE, Promislow DEL. Mortality in North American dogs from 1984 to 2004: an investigation into age-, size-, and breed-related causes of death. J Vet Intern Med. 2011;25(2):187-198. doi:10.1111/j.1939-1676.2011.0695.x
- 28.
Greer KA, Canterberry SC, Murphy KE. Statistical analysis regarding the effects of height and weight on life span of the domestic dog. Res Vet Sci. 2007;82(2):208-214. doi:10.1016/j.rvsc.2006.06.005
- 29.↑
Kraus C, Pavard S, Promislow DEL. The size-life span trade-off decomposed: why large dogs die young. Am Nat. 2013;181(4):492-505. doi:10.1086/669665
- 30.↑
Patronek GJ, Waters DJ, Glickman LT. Comparative longevity of pet dogs and humans: implications for gerontology research. J Gerontol A Biol Sci Med Sci. 1997;52(3):B171-B178. doi:10.1093/gerona/52a.3.b171
- 31.↑
Inoue M, Kwan NCL, Sugiura K. Estimating the life expectancy of companion dogs in Japan using pet cemetery data. J Vet Med Sci. 2018;80(7):1153-1158. doi:10.1292/jvms.17-0384
- 32.↑
Michell AR. Longevity of British breeds of dog and its relationships with sex, size, cardiovascular variables and disease. Vet Rec. 1999;145(22):625-629. doi:10.1136/vr.145.22.625
- 33.↑
Proschowsky HF, Rugbjerg H, Ersbøll AK. Mortality of purebred and mixed-breed dogs in Denmark. Prev Vet Med. 2003;58(1-2):63-74. doi:10.1016/s0167-5877(03)00010-2
- 34.↑
Westwood ME, Whiting PF, Kleijnen J. How does study quality affect the results of a diagnostic meta-analysis? BMC Med Res Methodol. 2005;5(1):20. doi:10.1186/1471-2288-5-20
- 35.↑
Mata F, Mata A. Investigating the relationship between inbreeding and life expectancy in dogs: mongrels live longer than pure breeds. PeerJ. 2023;11:e15718. doi:10.7717/peerj.15718
- 36.↑
Open data access. Dog Aging Project. Accessed April 18, 2024. https://dogagingproject.org/data-access
- 37.↑
McNulty KE, Creevy KE, Fitzpatrick A, Wilkins V, Barnett BG, Ruple A; Dog Aging Project Consortium. Development and validation of a novel instrument to capture companion dog mortality data: the Dog Aging Project End of Life Survey. J Am Vet Med Assoc. 2023;261(9):1326-1336. doi:10.2460/javma.23.02.0078
