If one of us humans was found birth a cheeky short sleep , there probably would n’t be a whole scientific survey on it . But for sharks , getting caught snoozing is an completely dissimilar thing , especially when some species need to keep moving to keep breathing , lest they end up napping for infinity . This was thought to be the case for gray reef sharks , until researchers chance them sleeping under Rand ledge in Seychelles .
biologist have historically considered grayreef sharksas ram ventilators , meaning they have to “ ram ” oxygen - fat water over their lamella to rest . “ On workaday survey dives around D’Arros we found grey reef sharks resting under coral reef ledges , ” state Dr Robert Bullock , the director of enquiry at the Save Our Seas D’Arros Research Centre ( SOSF - DRC ) in Seychelles and co - source of a study distinguish the determination , in astatement .
“ This is not something we believed they could do . The grey reef shark has been considered a Aries - ventilating species , ineffectual to lie , so to retrieve these ones resting turns our rudimentary understanding of them on its head . ”
So if thesharksaren’t using Aries breathing to breathe , what are they using instead ?
Researchers believe the evidence direct toward buccal pumping , which would postulate the sharks actively pump water over theirgillswhilst stationary , and it ’s thought they could do this for at least 40 minute at a time . confirm this theory , plunger observed flimsy downcast jaw movements in the resting shark . They also found shark facing in different counsel whilst at rest , suggesting they were not swear on currents to ram water over their gills .
This discovery , the squad believes , opens up a whole server of other questions . As Save Our Seas CEO and study author Dr James Lea explained : “ It ’s key to understanding how they use their environment and also how this may transfer in answer to shift in environmental conditions . How important is this rest , or potential sleep , for the sharks ? And what ’s the impact on them if they ca n’t get that residual if condition change , such as oxygen degree rising or fall due to achanging mood ? ”
Until those question are answered , the researchers trust the study will promote next enquiry and a re - examination of our existing apprehension of sharks . “ I hope that these finding serve as a reminder of how much we stilldo not knowand how exciting that is . Science is about being wrong quite a lot . And that ’s hunky-dory , ” said Bullock .
The study is publish in theJournal of Fish Biology .
