1 00:00:01,920 --> 00:00:06,360 Speaker 1: Welcome to brain Stuff production of I Heart Radio. Hey 2 00:00:06,400 --> 00:00:09,479 Speaker 1: brain Stuff. Lauren Vogelbaum here with a classic episode from 3 00:00:09,520 --> 00:00:13,480 Speaker 1: former host Christian Sagar. In this one, we dip into 4 00:00:13,560 --> 00:00:18,400 Speaker 1: questions about sleep. We humans sometimes have a strange relationship 5 00:00:18,440 --> 00:00:22,799 Speaker 1: with sleep, but what about other animals and specifically, what 6 00:00:22,840 --> 00:00:26,200 Speaker 1: about animals that are very different from us? Is a 7 00:00:26,239 --> 00:00:32,120 Speaker 1: brain necessary for sleep? Hey brain Stuff, it's Christian Sagar. 8 00:00:32,200 --> 00:00:34,600 Speaker 1: You probably don't think you have much in common with 9 00:00:34,640 --> 00:00:38,720 Speaker 1: a jellyfish. After all, their species don't share elemental properties 10 00:00:38,760 --> 00:00:41,040 Speaker 1: with you, like you know, a spine or a brain, 11 00:00:41,200 --> 00:00:44,479 Speaker 1: or even the same interests. The primitive jellyfish in the 12 00:00:44,560 --> 00:00:48,720 Speaker 1: genus Cassiopeia spends its time resting upside down on the 13 00:00:48,720 --> 00:00:51,599 Speaker 1: ocean floor, rather than you know, waiting for the next 14 00:00:51,640 --> 00:00:55,880 Speaker 1: season of Game Thrones. Researchers, though, have now discovered that 15 00:00:55,960 --> 00:00:59,640 Speaker 1: you and old Cassiopea are more like than anyone might 16 00:00:59,680 --> 00:01:03,120 Speaker 1: have spected. You both begin and end your days with 17 00:01:03,160 --> 00:01:07,600 Speaker 1: a little shut eye. Yes, jellyfish sleep. The study was 18 00:01:07,640 --> 00:01:13,720 Speaker 1: published online in the September edition of the journal Current Biology. 19 00:01:13,840 --> 00:01:18,560 Speaker 1: Unlike most jellyfish, Cassiopeia jellyfish often rest on the floor 20 00:01:18,720 --> 00:01:23,200 Speaker 1: of mangrove swamps and seagrass beds and rarely move from 21 00:01:23,200 --> 00:01:28,039 Speaker 1: their underwater spots. By lying upside down, the jellyfish exposes 22 00:01:28,080 --> 00:01:31,640 Speaker 1: the algae on its underside to the sun, allowing it 23 00:01:31,680 --> 00:01:36,319 Speaker 1: to photosynthesize and live off the food the algae produces. 24 00:01:36,600 --> 00:01:40,520 Speaker 1: Ravi Nath, the papers co first author and a graduate 25 00:01:40,560 --> 00:01:44,960 Speaker 1: student in cal texts Sternberg Laboratory, says that it may 26 00:01:45,000 --> 00:01:49,640 Speaker 1: not seem surprising that jellyfish sleep, after all, mammals sleep, 27 00:01:49,720 --> 00:01:53,080 Speaker 1: and other invertebrates such as worms and fruit flies sleep, 28 00:01:53,360 --> 00:01:57,360 Speaker 1: but Nath points out that jellyfish are the most evolutionary 29 00:01:57,520 --> 00:02:01,640 Speaker 1: ancient animals known to sleep. This finding opens up many 30 00:02:01,680 --> 00:02:05,440 Speaker 1: more questions, is sleep the property of neurons? And perhaps 31 00:02:05,840 --> 00:02:10,360 Speaker 1: a more far fetched question, do plant sleep? To test 32 00:02:10,400 --> 00:02:14,280 Speaker 1: whether the jellyfish were actually sleeping, researchers set up cameras 33 00:02:14,280 --> 00:02:17,880 Speaker 1: and found the jellyfish were largely inactive at night, and 34 00:02:17,919 --> 00:02:21,600 Speaker 1: they pulsed less during the day about thirty nine times 35 00:02:21,600 --> 00:02:25,320 Speaker 1: compared to fifty eight times during sunlit hours. Then the 36 00:02:25,360 --> 00:02:28,480 Speaker 1: team discovered it was harder to rouse the jellyfish at 37 00:02:28,600 --> 00:02:32,040 Speaker 1: night too. They set up a false bottom within the 38 00:02:32,120 --> 00:02:36,360 Speaker 1: jellyfish tank and pulled the platform out from under the jellyfish. 39 00:02:36,440 --> 00:02:40,200 Speaker 1: When alert during the day, the jellyfish immediately swam to 40 00:02:40,240 --> 00:02:43,120 Speaker 1: the bottom of the tank. At night, however, it took 41 00:02:43,440 --> 00:02:47,200 Speaker 1: several seconds for the jellyfish to awake before heading to 42 00:02:47,320 --> 00:02:51,120 Speaker 1: the tank floor. The researchers also demonstrated that sleep is 43 00:02:51,240 --> 00:02:54,959 Speaker 1: essential to jellyfish, just like it is to people. After 44 00:02:55,040 --> 00:02:58,400 Speaker 1: keeping the jellyfish awake during the night with pulses of water, 45 00:02:58,760 --> 00:03:02,120 Speaker 1: the jellyfish were slosh and sleepy the next day, when 46 00:03:02,160 --> 00:03:06,000 Speaker 1: they otherwise would have been active. Mondays am i right. 47 00:03:06,480 --> 00:03:10,639 Speaker 1: The discovery that jellyfish sleep could be an important next 48 00:03:10,720 --> 00:03:14,600 Speaker 1: step in sleep research for all types of species. While 49 00:03:14,639 --> 00:03:17,720 Speaker 1: the basis and function of sleep is still a mystery 50 00:03:17,760 --> 00:03:22,240 Speaker 1: to scientists, it's often associated with the brain because sleep 51 00:03:22,320 --> 00:03:27,120 Speaker 1: has a profound impact on memory and learning. Jellyfish don't 52 00:03:27,280 --> 00:03:31,280 Speaker 1: need a brain to sleep, which could be a revolutionary 53 00:03:31,360 --> 00:03:39,520 Speaker 1: concept for sleep science. Today's episode was written by Loaurel 54 00:03:39,600 --> 00:03:42,680 Speaker 1: Dove and produced by Tristan Neil and Tyler Playing. For 55 00:03:42,840 --> 00:03:45,000 Speaker 1: more in this and lots of other curious topics, visit 56 00:03:45,040 --> 00:03:47,680 Speaker 1: how stuff works dot com. Brain Stuff is a production 57 00:03:47,680 --> 00:03:50,240 Speaker 1: of I Heart Radio or more podcasts in My Heart radio, 58 00:03:50,360 --> 00:03:53,160 Speaker 1: visit the iHeart Radio app, Apple podcasts, or wherever you 59 00:03:53,200 --> 00:03:54,440 Speaker 1: listen to your favorite shows.