Research on pond snails shows about 2–3 hours of sleep-like rest per 2–3-day cycle, in short 22-minute bouts rather than a nightly block.

Most whales rest in short bouts across the day; sperm whales average about 7% of a day asleep, while other species likely total several hours.

Adult giraffes sleep in scattered catnaps totaling about 30–120 minutes per 24 hours, with brief REM while lying curled.

Bald eagle sleep roughly matches night length: they roost from dusk to dawn and take brief daytime rests during molt, winter, or bad weather.

Most adult dogs sleep 6–9 hours at night, with total daily sleep often landing between 12–14 hours depending on age and activity.

Sharks get brief, scattered rest—minutes to hours per day—varying by species and method, not deep human-style sleep.

Adult horse sleep totals about 3–5 hours per 24 hours, with 30–60 minutes of REM sleep that only happens when the horse lies down.

Wild foxes usually sleep 8–10 hours in 24 hours, with red foxes averaging about 9–10 hours and shifting rest around dawn, dusk, and night.