Sleep, work, and the effects of shift work in drug detector dogs Canis familiaris

Sleep-wake cycles of six drug detector dogs were video recorded, and the effects on them of shift work assessed. Observations were also recorded of interactions between dogs and their handlers during rest and work. Non-working dogs recorded immediately after work or at the same time of day or night when not scheduled for work, slept for 43 ± 16% (SD) of the 8-h recording sessions. They had 3.8 ± 1.2 sleep sessions per h, each of which lasted 7.2 ± 2.3 min. Active sleep occurred during 6.4% ± 4.8% of the total recorded time; there were 0.6 ± 0.4 active sleep sessions per h, each lasting on average 5.9 ± 3.8 min. The rhythms, duration and nature of active sleep were closely comparable with rapid eye movement (REM) sleep patterns recorded electrophysiologically by other workers; active and REM sleep in dogs are most probably identical. Patterns of sleep-wake cycles were not altered when handler-dog teams worked different day and night shifts. The ability of dogs to cope with changing shifts may be due to their natural brief and frequent sleep-wake cycles which may allow them sufficient and easy adjustment to changing routines. Two dogs examined after extended periods of not working showed a first-day-back-at-work effect in which active sleep on the following night was diminished, and less total time was spent asleep