We all know that sleep plays a vital role in human health and well-being. A full and restful night of shut-eye comes with countless benefits. It lets our bodies and minds mend and recover, and it permits us to wake up each morning with more energy and vigor to face the challenges of the day (usually). During a typical night of sleep, humans experience between four and six sleep cycles. All told, REM sleep—that coveted state where the mind and body rests and heals deeply—accounts for about a quarter of a healthy adult’s total sleep for a given night.

But if you assume these sleep requirements apply to the animal kingdom, think again. Animals have devised fascinating ways to rest while on the go, maintaining enough alertness to evade predators trying to surprise them during a snooze fest. Bullfrogs prove so good at this strategy that scientists once assumed they didn’t sleep at all. But recent research provides a more nuanced perspective.

Strategic Snoozing in the Animal Kingdom

Sleep can get you killed in the wild. After all, many predators are nocturnal, and they don’t have any qualms about waking up their prey mid-bite. As a result, animals have developed unique ways to rest while still maintaining enough awareness to avoid becoming a lion’s midnight snack.

These adaptations have provided scientists with a greater understanding of sleep functions in animals and humans alike. They also offer fascinating insights into the secret lives of animals, from dolphins to giraffes.

The Marvels of Unihemispheric Sleeping

For example, dolphins rely on unihemispheric sleep for rest while remaining on guard for predators. How do they pull off such a nifty trick? While one hemisphere of their brain rests, the other side stays active. Alternating between both hemispheres, dolphins ensure enough rest for their whole brain without becoming great white shark bait.

Two dolphins looking at camera

jeffk42 via Flickr (CC BY-NC 2.0)

The same goes for Alpine swifts. While migrating to southern Africa, they often spend up to 200 days in the air, experiencing uninterrupted flight. But, like dolphins, they also partake in unihemispheric rest.

The Masters of Power Napping

As for giraffes? They sleep in short bursts and prove capable of falling into deep sleep phases quickly and irregularly. What about other animals? Horses nap for approximately 15 minutes at a time, either lying down or standing. They get their best sleep in groups, with at least one individual keeping watch over the rest of the herd.

Sleeping giraffe

Sum_of_Marc via Flickr (CC BY-NC-ND 2.0)

As you can see, animals have developed amazing and unique ways to get a little sleep while staying safe from predators. But how do bullfrogs fit into the mix?

Resting Versus Sleeping

Are bullfrogs unihemispheric sleepers like dolphins and Alpine swifts, or do they indulge in short power naps like giraffes and horses? Are the myths true about bullfrogs not requiring any sleep at all? The short and sweet answer to each of these questions is “no.” Instead, they “rest” throughout the day. But these brief dalliances with a nap never quite reach an inattentive state.

Of course, that doesn’t mean they go their whole lives without catching their Zzzs, either. Instead, consider them binge sleepers. They rest lightly throughout their active months, but when hibernation season comes around, they dive in deep… to sleep, that is. As for resting during non-hibernation months? Can we call that sleep? It depends on who you ask.

American bullfrog in water

matthewbeziat via Flickr (CC BY-NC 2.0)

More Research Needed

A 1967 study concluded that bullfrogs showed the same response time whether fully awake or resting. As a result, they concluded, perhaps erroneously, that these frogs don’t sleep at all. But since that time, other scientists have raised concerns about how the bullfrogs were tested. Researchers like Chiara Cirelli and Giulio Tononi have argued that “more experiments are needed before concluding that bullfrogs do not sleep.”

Until this research gets conducted, the final word on bullfrog beauty sleep remains up in the air. But we can say with certainty that, like college students after finals, binge sleeping bullfrogs know how to make up for lost time come hibernation.

By Engrid Barnett, contributor for Ripleys.com


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