Can Animals Without A Brain or Central Nervous System Sleep?
Do all animals sleep? This is the question Paul Stemberg, researcher at Caltech's Howard Hughes Medical Institute, wanted to find out. Scientists know all vertebrates that have been studied do sleep. But what about invertebrates? Scientists have suggested that fruit flies and roundworms do sleep. Do more primitive organisms like sponges and jellyfish sleep?
The Upside-Down Jellyfish
To answer this question Paul Sternberg turned his attention to the upside-down jellyfish, a member of the jellyfish genus Cassiopea.
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The upside-down jellyfish is a mostly stationary animal that prefers the warm shallow waters associated with mudflats and mangrove swamps. This jellyfish resembles a cauliflower or an upside-down mushroom when resting on the ocean floor with its tentacles curled upwards.
Like other jellyfish the upside-down jelly fish does move, pulsing at a steady rate.
Does the Upside-Down Jellyfish Sleep?
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On September 21 scientists observed a jellyfish, for the first time, in a sleep-like state. They found that the jellyfish's pulsating movement slowed at night but awakened, becoming more animated, when food was dropped into its environment.
For further proof the scientists allowed the jellyfish to rest on a suspended false-ocean floor. Then the scientist dropped the floor to observe the jellyfish's behavior. They found that the jellyfish quickly swam to the bottom when the floor was dropped, however the jellyfish's dissent was observed to be considerably slower at night. This gave scientists further evidence that the jellyfish was in a state of slumber at night.
The scientists also discovered that after a disrupted sleep the jellyfish pulsed less, but after catching up on its sleep the pulsing returned to a normal rate.
On to More Complicated Questions
Researchers will be moving on to even more complicated questions about whether all animals sleep. Like do you need to be more than an one celled organism to sleep?
Sources and Full Articles
Scientists spot sleeping jellyfish, Gears of Biz, 23 September 2017
ELLYFISH SLEEP AT NIGHT EVEN IF THEY DON’T HAVE A BRAIN, The Monitor Daily, 23 September 2017
Thank You!
Thank you!
as far as I know, animals also have to sleep to rest. maybe the sleeping animals are different from us as human beings. although they sleep, their conscious instinct is maintained, to avoid the predators who want to eat it.
I think you are correct that all animals sleep, but not always the ways humans perceive sleep.
Have a great week!
Steem on,
Mike
I don't know, if you drop lasagna in my bed I'll wake up right quick and ask where the beer and garlic bread is.
LOL!!
Just the smell of bacon usually wakes me up :)
Have a great weekend!
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Mike
Thank you for posting this lovely moment in time for you. Followed...
it is a very tiring work .. to examine whether the marine animals are sleeping or resting .. but I think it's a full-fledged job ,, until today I also always think about the animals that live in the water what he is sleeping or not .. love has shared knowledge and information very useful.
Super interesting! Honestly never even thought about whether or not jellyfish sleep. Now I know they do (or at least rest).
Yes, I found this topic interesting too. Because, like you, I never really thought about it.
Have a great weekend!
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Mike
Wow Amazing.