Family Dogs’ Sleep Macrostructure Reflects Worsened Sleep Quality When Sleeping in the Absence of Their Owners: A Non-Invasive Polysomnography Study

TL;DR

Dogs sleep worse when their owners are not nearby, as shown by changes in their sleep patterns measured through non-invasive methods.

Contribution

First non-invasive polysomnography study showing dogs' sleep quality worsens when owners are absent.

Findings

Dogs had shorter sleep onset time and higher sleep efficiency when sleeping with their owners.

Dogs spent more time in deep sleep (non-REM) when their owners were present.

Sleep latency increased and sleep efficiency worsened when owners were absent.

Abstract

Dog owners co-sleeping with their pet is a widely debated topic. Empirical data show that co-sleeping generally worsens owners’ sleep quality, although this is not reflected in their subjective reports. The effects on dogs’ sleep quality, however, have not been investigated. The present study provides the first evidence that dogs manifest different sleep patterns when sleeping in the presence versus in the absence of their owners. Sleeping together with the owner in an unfamiliar environment resulted in dogs’ shortened sleep onset time, increased sleep efficiency, and specifically spending more time in deep sleep, compared to sleeping with a friendly, unfamiliar human, who was not their owner. These findings align with the well-known fact that dogs show human-like attachment towards their owners.

Family dogs stand out with regard to their special (human-like) attachment behavior towards their owners. This dog–owner attachment bond, analogous to the human infant–mother relationship, has been extensively documented at the behavioral level. Capitalizing on the fully non-invasive polysomnography protocol, the current study compares family dogs’ sleep structure when sleeping in the company of their owners versus an experimenter (a friendly stranger human). Subjects (N = 9) participated in three recording sessions, each lasting 3 h. The first session served as an adaptation to the recording environment, while the second and third were the test sessions analyzed for the present paper. On these two occasions, dogs slept, in a counterbalanced order, once in the company of their owner, while on the other occasion they slept in the company of an experimenter, while the owner was outside the room. Polysomnography recordings were used to extract high-resolution information (in 20 s epochs) on the time dogs spend awake and in each of the sleep stages (drowsiness, non-REM, and REM). Our results show a robust difference between dogs’ sleep structure with and without the owner. In addition to an increased sleep latency and worsened sleep efficiency, dogs spent considerably less time in deep sleep (non-REM) when their owner was absent. These findings add to the increasing body of literature dealing with dog-to-owner attachment and provide unique physiological evidence for the phenomenon, complementing the widely reproduced behavioral data.

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