Sort of like asking the question “Do fish sleep?” If you’ve ever pondered that one, the answer is, yes – they just don’t close their eyes like us humans. That’s because they don’t have eyelids. It doesn’t mean the majority of them sink to the bottom of the pond and curl-up in their tiny beds. And they don’t have anything like REM sleep. But they do slow down their metabolism, while continuing to swim.

There are a few fish that will fall to the bottom on the water. Try this experiment. With your goldfish, you’ll notice them hovering at the bottom of the tank. You can tell they’re nodding-off by sprinkling a few flakes of food at the surface. They won’t immediately soar to the top for the grub. It takes them a few moments to shake-it off before they rise to their food. It’s almost as if it they need to rub the sleep from their eyes to pop into consciousness. Like us, they have a delay when they’re just waking up.

What is Sleep in the Insect World?

Simply speaking, it’s the opposite of being awake. The bug doesn’t respond right-off the bat. Most times insects “sleep” but they do so with one eye open – figuratively speaking.

Their movement is slowed to a snail’s pace. While we can tell when other members of the animal kingdom are deeply snoozing by measuring the heart rate or their lack of brain patterns, how do you measure this in your basic bug?

One way we have figured it out is by knowing that the lower the temperature, the crawlie goes into a state of suspended animation – AKA hibernation. Those insects that don’t experience this long bear-in-the-cave coma-like state generally catch a few ZZZZ’s and we can tell by how lethargic they are when we observe them. Kind of like the goldfish at that bottom of the aquarium. It takes the creature a few moments to shake-off their unconscious state. By this, we know they are regenerating to pest us when they snap to attention.

Take butterflies for example. During migration season, large colonies huddle together at night. With folded wings, they’re off to the bug-world’s version of dreaming. Another species – the dragonfly – use sunset to nap-away. If you ever want to catch a dragonfly, wait until they’re groggy. It will be much easier to net them.

Photo By: Michael Yang Photography

Feigning Death

A Harvard study suggests that members of the animal kingdom – of which insects are a part of – somewhat invented sleep.

“One of the earliest theories of sleep, sometimes called the adaptive or evolutionary theory, suggests that inactivity at night is an adaptation that served a survival function by keeping organisms out of harm’s way at times when they would be particularly vulnerable. The theory suggests that animals that were able to stay still and quiet during these periods of vulnerability had an advantage over other animals that remained active. These animals did not have accidents during activities in the dark, for example, and were not killed by predators. Through natural selection, this behavioral strategy presumably evolved to become what we now recognize as sleep.”

In other words, sleep may have been invented and not some natural thing that simply shot out of the clear blue. It’s called “death feigning.” If you look dead to other predators, they’ll move on looking for fresh food.

Check out a caterpillar when it’s feigning death. It takes on a really weird position. Cutworms roll-up into a ball. A pillbug when it feels threatened does pretty much the same thing. Beetles suck their legs close to their bodies and roll-over on their backs. Looks pretty dead. Yet it’s not, it’s pretending that it’s no longer worth a bucket of spit to a would-be predator.

How long will an insect play dead? Usually until the exterminator leaves. But seriously, just a few minutes. Some simulate death for hours. Like the extremely large water bug.

It holds the record so far. It pretends that it is bereft of life for up to 8-hours. The only thing we know that make-believes it has passed to another lifetime are rocks. Some seem to sleep forever.

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