Hungarian scientists found that dogs with short muzzles sleep more hours a day compared to dogs with long muzzles. Moreover, brachycephalics have longer REM sleep phases than slow-wave sleep phases.
During the study, the sleep state of 92 pet dogs was analyzed. Scientists used electroencephalography (EEG) to record brain electrical activity during sleep and found that brachycephalic dogs spend more time in the rapid eye movement (REM) sleep phase, which is characterized by high brain activity. This resembles the sleep of infants, researchers noted.
Additionally, an increase in sleep spindles (rhythmic patterns of brain activity observed on EEG) was recorded in the slow-wave sleep phase for brachycephalics. In humans, this is usually associated with memory impairment, while in dogs, it is linked to reduced trainability during training.
There was also a noted predisposition for flat-faced dogs to experience apnea (snoring) and increased daytime sleepiness. “Some of these dogs sleep with a ball in their mouth, and people find this cute, but in reality, they need it to maintain open airways,” commented the study's results by Kari Ekenstedt, an assistant professor at Purdue University's College of Veterinary Medicine, as quoted by The Guardian.
According to researchers, the findings may indicate that dogs with short muzzles have retained a sleep pattern characteristic of puppyhood. Furthermore, it has been established that such dogs may experience potentially harmful changes in the brain due to their muzzle shape.
The study results were published in the journal Brain Structure and Function.
