Since most amphibians are nocturnal and are far more active at night, it has mainly been assumed that frogs do not sleep at all.
However, recent scientific studies have found evidence to prove that frogs sleep based on intermediate periods of Non-REM, Primary, and Cataplectic Sleep. Still, there are plenty of questions surrounding where they reside while during resting sessions.
Generally, aquatic frogs rest in water, arboreal frogs rest in trees, and terrestrial frogs sleep underground, though this may depend on the species, location and time of year including hibernation and estivation periods.
There is still a lack of widespread research into frog sleeping behaviors, as the general concept of sleep may not always apply to amphibians. While sleep is a routine aspect of frogs’ lives, they do not sleep the same way that humans or mammals sleep.
Frogs typically choose their rest areas depending on the species and frog type, as various frogs have different habits and traits. The locations used for periodic sleep are primarily the same as the species-dependent locations chosen to hibernate through winters (brumation) or estivate through extreme heats.
Regardless of the type of rest that frogs choose at varying points throughout the day, they predominantly choose sleeping areas based on their species type since these areas are most supportive of their needs.
Most frogs are more active at night, and it is believed that they may rest more throughout the day when the sun is hot.
Join us as we discuss how frogs sleep and which areas they typically choose for resting periods.
Where Do Terrestrial Frogs Sleep?
Terrestrial frog species would typically dig or burrow their way into moist, soft, and loose soil during the day to rest. They often venture into these crevices and burrows at numerous points throughout the day and may experience lower activity periods of rest while underground.
Ground-dwelling frogs are generally nocturnal and are active incredibly at night, ambushing prey or lying in wait as they anticipate their next meal.
They are capable of remaining immobile for long periods of time overall, but they can respond to potential food or predators immediately.
Where Do Aquatic Frogs Sleep?
Aquatic frogs need much more water to survive compared to other frog types, and they can usually be found along the water’s edge. They generally rest submerged in water amongst suitable vegetation during the day.
Examples of aquatic frogs that have been observed in sleep-like states include Northern Leopard Frogs, Green Frogs, and American Bullfrogs.
Like most frogs, aquatic frog species are typically far more active at night. They can often be found on land near water sources such as banks and wetlands as they scavenge the area in search of food sources.
Where Do Arboreal Frogs Sleep?
Arboreal frogs, otherwise known as tree frogs, can generally be found in sleep-like positions throughout the day.
For example, Gray Tree Frogs often reside on horizontal branches in trees with their limbs tucked under their bodies and their chins and bellies close to the branches.
Other arboreal species, such as Spring Peepers and Wood Frogs, use similar behaviors during resting periods.
How Do Frogs Sleep?
Frogs generally sleep based on intermediate period of Non-REM, Primary and Cataplectic Sleep. Frogs do not sleep like humans other mammals, yet few scientific studies have been carried out on the topic of frog sleep, and many existing studies are based on a mammal-centric definition of sleep.
Frogs sleep differently compared to humans and other mammals, according to Karmanova (1982), who discovered primary sleeping methods employed by frogs (CTNF). Typical sleep characteristics have been observed in most animals, such as mammals like humans and birds.
From a human standpoint, sleep can be defined by numerous factors, including the vibration in brain waves and specific brain activity.
Certain characteristics should ideally be present in order for one to dictate that the subject is asleep, according to the scientific definition. Two specific types of sleep are common amongst mammals, namely Non-REM, otherwise known as Slow-Wave Sleep (quiet sleep), and REM, otherwise known as Paradoxical Sleep (active sleep).
However, since frogs are ectothermic creatures, many of their physical and behavioral traits do not align with typical factors and definitions.
They do go into a sleep-like state where they are immobile, but they regulate their body temperatures differently and have a different brain structure.
It is fairly straightforward to identify a frog that is asleep, regardless of the type of sleep, frog type, or location.
Their behaviors closely resemble what humans know as sleep in most cases, and a sleeping frog can be identified using the following behavioral cues:
- Resting in immobile states for long periods of time.
- Tucking their front and hind limbs underneath their bodies.
- Keeping their chins and bellies close to the ground or resting surface.
- Covering their eyes with their nictitating membranes, known as third eyelids.
Using these behaviors during sleeping sessions allows frogs to rest up while still being aware of and engaged with their surroundings (CTNF).
Their nictitating membrane enables frogs to see and react to their surroundings, as being asleep and completely oblivious to the nearby dangers and ongoings is incredibly risky in the wild.
Frog Sleeping Methods
Karmanova (1982) observed three different sleep-like states that could be considered sleeping considering the inherent differences in genetics and behavior. Frogs utilize these sleeping methods at varying times throughout the day and for numerous purposes.
Below are the three sleeping states identified by Karmanova:
|Sleeping State||General Description of Frog Sleeping State|
|Primary Sleep||Resting state during the day, and the frogs’ eyes remain open.|
|Catatonic Sleep||Resting state at night, and the frogs’ muscles are often rigid.|
|Cataplectic Sleep||Resting state at night, frogs may have atonia.|
Based on the definition and characteristics of sleep defined by humans, frogs have various similarities and differences.
However, these are primarily due to their genetic features, and their behavior could still be viewed as sleep overall.
Below are the similarities and differences between the behavior and body activity of frogs and other animals:
|Sleep Characteristic||Frogs Sleeping||Other Animals Sleeping|
|A period of immobility||Yes||Yes|
|Rapid eye movement||No||Yes|
|Slower breathing rate||Yes||Yes|
|Lower brain temperature||N/A (Ectothermic)||Yes|
|Lower metabolic rate||Yes||Yes|
|Slower heart rate||Yes||Yes|
Although frogs do not utilize the same sleeping methods or locations as humans and other mammals, they still need to rest and recuperate as much as any other creature.
Frogs are incredibly skillful, and they know what they need to survive. They choose their sleeping locations based on these needs to ensure their longevity and often apply unique sleeping tactics to increase their survival chances in the wild.
Learn more about frog sleep and activity on our blog:
- Do Frogs Sleep?
- Where Do Frogs Go During The Day?
- What Do Frogs Do At Night?
- 9 Things You Can Do About Loud Frogs at Night
- 8 Incredible Frog Eye Facts
- How Do Frogs Survive?
Karmanova, I. G., Evolution of Sleep: Stages of the Formation of the “Wakefulness-Sleep” Cycle in Vertebrates. 1982. Karger, Basel, Originally Published in Russian by Nauka Publishers, Leningrad.