Sharks ' prominent - than - liveliness place in pop culture has fueledmany myth , from their reputation as unmindful man - eaters to the misconception thatthey do n’t get cancer . Another long - held shark feeling is now the subject of a new scientific written report . AsSmithsonianreports , some sharksdosleep , even though they appear to be wide - awake when they ’re catch up on theirsZs .
The idea that sharks never log Z’s add up from the fact that sharks of certain specie must be in constant motility to keep oxygen - rich water hang through their gill . If they stay still for too long , they ’ll asphyxiate and croak .
This is n’t true of all sharks , however . Draughtsboard sharks , a bottom - dwelling species native to the waters near New Zealand , arebuccal pumping sharks , meaning they expend their throat to crowd piss through their respiratory system when they ’re not drown . For their study published in the journalBiology Letters , researchers from the School of Life Sciences at La Trobe University in Australia and the Institute of Marine Science at the University of Auckland in New Zealand followed these sharks for 24 - hour periods . They found that draughtsboard sharks that outride still for five bit or longer consumed less oxygen than when they were active . Previous researchconducted by the same squad determine that motionless draughtsboard sharks were obtuse to reply to stimulant . Both findings are signs of sleep in other species , indicating that draughtsboard shark may be enter a Department of State of rest when they terminate move .
Draughtsboard sharks may some share nap habits with other metal money , but other bedtime conduct search less familiar . Thirty - eight pct of the shark in the studykept their eyes openat nighttime even when they showed signs of slumber . They were more probable to fill up their eyes while resting during the day , hint that extraneous light is an work factor on the demeanour , the study authors theorise .
The scientists behind the paper title their research put up " the first physiological evidence of sleep in sharks . " But there are still a lot questions to answer about this mysterious aspect of shark life sentence , including how other metal money rest — if it all . The team plans to analyze the brain activity of draughtsboard shark during quietus as part of the next phase of their research .
[ h / tSmithsonian ]
