Characterizing sleep-wake cycles in dogs (Canis lupus familiaris) using daytime activity levels, sex, and temperament: a longitudinal comparison

Abstract

Across many species, sleep patterns are associated with variables such as age, sex, daytime activity levels, and temperament. Yet, current research lacks an in-depth characterization of dog sleep patterns and how they vary according to these variables during the critical developmental period of young puppyhood. Such studies are crucial in order to establish dogs as a model organism for studies of sleep and for additional applications in the realms of dog welfare and training. In the present study, we characterized how often and for how long young dogs wake, as well as their barking patterns during sleep. We evaluated sleep behaviors for dogs aged 8-18 weeks and determined longitudinal patterns using a sample of Canine Companions service-dogs-in-training (N=21). Video recordings of dogs were analyzed using a novel coding scheme to determine duration and frequency of awake bouts and barking. Mixed-effects logistic regression models reveal that awake-bout length (minutes) and frequency did not vary significantly by weeks of age, daytime activity levels, or temperament. However, we did find significant sex differences in awake bout length (p<0.009). These results suggest distinct daytime and nighttime temperaments, as well as the importance of this developmental period for developing adultlike sleep patterns. Further study is required to examine sleep behaviors in puppies beyond 18-weeks to better understand how adultlike patterns emerge and the stability of the patterns observed in this study.