WEBVTT - BrainStuff Classics: Do Jellyfish Sleep?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio. Hey

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<v Speaker 1>brain Stuff. Lauren Vogelbaum here with a classic episode from

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<v Speaker 1>former host Christian Sagar. In this one, we dip into

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<v Speaker 1>questions about sleep. We humans sometimes have a strange relationship

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<v Speaker 1>with sleep, but what about other animals and specifically, what

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<v Speaker 1>about animals that are very different from us? Is a

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<v Speaker 1>brain necessary for sleep? Hey brain Stuff, it's Christian Sagar.

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<v Speaker 1>You probably don't think you have much in common with

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<v Speaker 1>a jellyfish. After all, their species don't share elemental properties

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<v Speaker 1>with you, like you know, a spine or a brain,

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<v Speaker 1>or even the same interests. The primitive jellyfish in the

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<v Speaker 1>genus Cassiopeia spends its time resting upside down on the

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<v Speaker 1>ocean floor, rather than you know, waiting for the next

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<v Speaker 1>season of Game Thrones. Researchers, though, have now discovered that

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<v Speaker 1>you and old Cassiopea are more like than anyone might

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<v Speaker 1>have spected. You both begin and end your days with

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<v Speaker 1>a little shut eye. Yes, jellyfish sleep. The study was

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<v Speaker 1>published online in the September edition of the journal Current Biology.

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<v Speaker 1>Unlike most jellyfish, Cassiopeia jellyfish often rest on the floor

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<v Speaker 1>of mangrove swamps and seagrass beds and rarely move from

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<v Speaker 1>their underwater spots. By lying upside down, the jellyfish exposes

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<v Speaker 1>the algae on its underside to the sun, allowing it

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<v Speaker 1>to photosynthesize and live off the food the algae produces.

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<v Speaker 1>Ravi Nath, the papers co first author and a graduate

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<v Speaker 1>student in cal texts Sternberg Laboratory, says that it may

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<v Speaker 1>not seem surprising that jellyfish sleep, after all, mammals sleep,

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<v Speaker 1>and other invertebrates such as worms and fruit flies sleep,

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<v Speaker 1>but Nath points out that jellyfish are the most evolutionary

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<v Speaker 1>ancient animals known to sleep. This finding opens up many

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<v Speaker 1>more questions, is sleep the property of neurons? And perhaps

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<v Speaker 1>a more far fetched question, do plant sleep? To test

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<v Speaker 1>whether the jellyfish were actually sleeping, researchers set up cameras

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<v Speaker 1>and found the jellyfish were largely inactive at night, and

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<v Speaker 1>they pulsed less during the day about thirty nine times

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<v Speaker 1>compared to fifty eight times during sunlit hours. Then the

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<v Speaker 1>team discovered it was harder to rouse the jellyfish at

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<v Speaker 1>night too. They set up a false bottom within the

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<v Speaker 1>jellyfish tank and pulled the platform out from under the jellyfish.

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<v Speaker 1>When alert during the day, the jellyfish immediately swam to

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<v Speaker 1>the bottom of the tank. At night, however, it took

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<v Speaker 1>several seconds for the jellyfish to awake before heading to

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<v Speaker 1>the tank floor. The researchers also demonstrated that sleep is

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<v Speaker 1>essential to jellyfish, just like it is to people. After

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<v Speaker 1>keeping the jellyfish awake during the night with pulses of water,

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<v Speaker 1>the jellyfish were slosh and sleepy the next day, when

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<v Speaker 1>they otherwise would have been active. Mondays am i right.

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<v Speaker 1>The discovery that jellyfish sleep could be an important next

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<v Speaker 1>step in sleep research for all types of species. While

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<v Speaker 1>the basis and function of sleep is still a mystery

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<v Speaker 1>to scientists, it's often associated with the brain because sleep

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<v Speaker 1>has a profound impact on memory and learning. Jellyfish don't

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<v Speaker 1>need a brain to sleep, which could be a revolutionary

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<v Speaker 1>concept for sleep science. Today's episode was written by Loaurel

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<v Speaker 1>Dove and produced by Tristan Neil and Tyler Playing. For

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<v Speaker 1>more in this and lots of other curious topics, visit

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<v Speaker 1>how stuff works dot com. Brain Stuff is a production

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