Snails are fascinating creatures. They’re hermaphrodites. The diameter of their shells can be microscopic to over a few feet. Their greatest weakness is lack of moisture, and salt can kill them.
But the fascinating facts don’t stop there. Snails also have bizarre sleeping habits. They can sleep for hours at a time or for up to three years.
Yes, three years. Read on to learn more about the fascinating sleep habits of snails.
How long do snails sleep?
According to a 2011 study, researchers found that the sleep cycle of snails tends to follow a two to three day period, as opposed to the 24 hour cycle of humans. Even more interesting, they found that within that two to three day period, snails will experience seven periods of sleep over the first 13 to 15 hours, followed by 30 hours of alertness and activity.
How does snail sleep differ from humans and other animals?
Many animals, including humans and other mammals, have sleep patterns that roughly follow the patterns of the sun.
That’s because sunlight influences our circadian rhythms, which control our sleep, appetite, and other biological functions.
Many mammals appear to cycle through different stages of sleep, just like we do. However, the time they spend in each stage of sleep, and the total time they spend asleep, can vary wildly from humans, based on the evolutionary needs of each species.
When it comes to sleep, there’s a lot of variety in the animal world. For instance, other animals have sleep cycles that extend well beyond the sun’s natural 24-hour cycle. This is true of snails.
How did the researchers perform their snail sleep study?
Our brain waves change as we progress through different sleep stages. When researchers observe animals in a laboratory setting, they’ll monitor their brain waves along with other cues, like heart rate, to determine when they’re asleep or awake.
However, it’d be quite difficult to monitor the brain waves of snails. So, the researchers found another way to determine whether they were asleep or awake, but resting.
The first cue that a snail was asleep was that it would spend a period of time attached to the side of its tank, with its tentacles somewhat withdrawn and its feet relaxed and in line with each other. Then, the researchers assessed each snail’s alertness by tapping its shell, poking it with a metal rod, and presenting a sucrose solution to whet their appetite.
When they were relaxing, the snails responded twice as quickly to the taps and nudges, and seven times faster to the presence of sucrose.
This gave the researchers a clear indication of whether they were asleep or awake.
Snails hibernate, too.
The Toronto study analyzed the daily sleep patterns of snails in a controlled environment.
However, snails in the wild may also hibernate, in order to avoid starvation or inclement weather. Snails need moisture to survive, so during hibernation, they’ll withdraw into their shells and secrete a layer of mucous. This is known as estivation, and it enables snails to hibernate for up to three years at a time—or until conditions improve. They’ll stay inside their shells until food becomes more available or the weather becomes safer for them to come back out.
Is snail sleep really that unique?
Snails aren’t the only animals with unique sleep habits. Many birds and marine mammals let one side of their brain sleep, while the other continues functioning, allowing them to fly, float, or breathe. Talk about multi-tasking!