Age influences domestic dog cognitive performance independent of average breed lifespan

Abstract

Across mammals, increased body size is positively associated with lifespan. However, within species, this relationship is inverted. This is well illustrated in dogs (Canis familiaris), where larger dogs exhibit accelerated life trajectories: growing faster and dying younger than smaller dogs. Similarly, some age-associated traits (e.g., growth rate and physiological pace of aging) exhibit accelerated trajectories in larger breeds. Yet, it is unknown whether cognitive performance also demonstrates an accelerated life course trajectory in larger dogs. Here, we measured cognitive development and aging in a cross-sectional study of over 4000 dogs from 66 breeds using nine memory and decision-making tasks performed by citizen scientists as part of the Dognition project. Specifically, we tested whether cognitive traits follow a compressed (accelerated) trajectory in larger dogs, or the same trajectory for all breeds, which would result in limited cognitive decline in larger breeds. We found that all breeds, regardless of size or lifespan, tended to follow the same quadratic trajectory of cognitive aging-with a period of cognitive development in early life and decline in later life. Taken together, our results suggest that cognitive performance follows similar age-related trajectories across dog breeds, despite remarkable variation in developmental rates and lifespan.

How Old Is My Dog? Identification of Rational Age Groupings in Pet Dogs Based Upon Normative Age-Linked Processes

“…In the domestic dog, the diversity of physical conformation and breed-related features (such as body size) means that aging can impact dogs in varying ways, dramatically effecting longevity and morbidity (1)(2)(3)(4)(5). The impact of aging on behavior is also not straightforward (Figure 1), as age can have a linear relationship with certain behavioral traits [e.g., (6,9)] but a quadratic relationship with others [e.g., (7,10,11)] or exhibit a steep change in later life [e.g., (6,12)]. Because of the impact of age on behavior and health, age must always be considered in any study that includes dogs at differing stages of development.…”

“…However, categorizing shorter-lived breeds as geriatric when arguably still young is based upon physical health needs and may not reflect age-related processes, including behavioral or cognitive aging. Indeed, two studies that have evaluated breed differences in behavioral aging both found no evidence for an increased rate of change in the behavior of large, short-lived breeds (10,22) with all dogs, irrespective of their anticipated lifespan, expected to follow the same lifespan trajectory. Using the term "geriatric" to describe dogs with shorter anticipated lifespans may serve to normalize their early mortality, thus masking breed-associated welfare issues.…”

Cooperative Communication with Humans Evolved to Emerge Early in Dogs

“…Second, the interspecific communicative abilities of dogs emerge early (19). While dogs can become more skillful using human gestures with age and training (20,21), the use of human gestures does not require intensive exposure to humans. Around the age of weaning (~7-9 weeks) dog puppies already use human gestures (4,8,22), with free ranging dog puppies and litter-reared assistance dog puppies succeeding with multiple gestures on their very first experimental trial (11,23).…”

Man’s best friend in life and death: scientific perspectives and challenges of dog brain banking

“…1c). The manifold benefits of involving owners in the longitudinal screening of dogs have already led to the initiation of citizen science approaches to gather behavioral data from a large number of pet dogs [124][125][126][127]. Well-designed citizen science methods can also provide feedback to the owners and invite them to actively discuss issues with their dogs in specific social forums, where professionals are also present.…”