Published in Frontiers in Veterinary Science, the perspective review by Naomi D. Harvey addresses a long-standing challenge in canine science: the absence of standardized age categories for research. Studies of learning, memory, behavior, and cognitive decline often use inconsistent age thresholds, making comparisons difficult and obscuring patterns of normal versus pathological aging.
The review synthesizes evidence showing that canine behavioral and cognitive development follows predictable trajectories across the lifespan. By proposing rational chronological categories, Harvey argues that researchers can better map age-linked developmental processes and distinguish typical aging from early signs of cognitive dysfunction. These categories also offer practical value for educators and dog owners seeking to understand expected behavioral changes as dogs mature.
Importantly, the proposed groupings capture patterns relevant to most breeds, though they are not meant to represent health-related needs tied to breed-specific morbidity. Short-lived breeds such as the Great Dane present a striking example: despite their markedly shorter lifespan, they do not appear to age cognitively faster. Instead, they are more likely to die during stages classified as Mature Adult rather than progressing into the oldest age groups.
Harvey concludes that standardized age categories would strengthen future research by enabling cross-study comparisons and identifying deviations from normative aging. Such clarity has the potential to improve early detection of cognitive decline, guide welfare interventions, and align behavioral expectations across a dog’s life.
Source: Harvey, N. D. (2021). How Old Is My Dog? Identification of Rational Age Groupings in Pet Dogs Based Upon Normative Age-Linked Processes. Frontiers in Veterinary Science. Published April 27, 2021.
