Do sharks get their ZZZs? New evidence shows it’s not all about the hunt —

The primary physiological proof that sharks take a break from monitoring prey to catch just a few winks has been uncovered by a Simon Fraser College researcher who makes a speciality of sleep amongst aquatic creatures, from sharks to crocodiles.

Comparative sleep physiologist Mike Kelly, a postdoctoral analysis fellow in SFU’s Circadian Rhythms and Sleep Lab and Translational Neuroscience Lab, studied the metabolic signatures of sleep and behavioural sleep indicators amongst New Zealand’s draughtsboard sharks.

His analysis discovered that they produced a decrease metabolic price and recumbent physique posture when inactive for longer than 5 minutes, supporting the concept that they have been conserving power by sleeping.

The findings are printed this week in Biology Letters.

Kelly and researchers noticed the sharks over 24-hour durations and tracked their metabolic charges and conduct throughout swimming, resting and suspected sleep durations.

“The sharks confirmed a dramatic lower of their metabolic price and an apparent postural change following 5 minutes of inactivity, which demonstrated a definite separation between durations of quiet wakefulness and sleep,” says Kelly.

Whereas it’s identified that many animals sleep, together with bony fish species, Kelly says the analysis offers the primary physiological proof of sleep amongst elasmobranchs, a fish group that features sharks, rays and skates.

Kelly earlier studied sleep conduct amongst crocodiles for his Honors thesis at Australia’s La Trobe College. The analysis — that discovered that these creatures doubtless sleep with one eye open — was later printed within the Journal of Experimental Biology.

Along with sleep analysis with sharks, which started as his PhD thesis on the College of Western Australia, Kelly has turn out to be well-versed within the circadian rhythms and sleep conduct of many different fish species and has prolonged his work to incorporate associated behaviors in octopuses.

“I discover the easiest way to beat my sheer terror of those creatures of the deep is to rise up shut and private with them,” Kelly says. “Moreover, higher to be round them once they’re sleeping than once they’re able to feed!”

Kelly continues to study extra about shark conduct via inspecting the primary wi-fi recordings of mind exercise in each anesthetized and freely behaving sharks.

At SFU he’s additionally investigating how traumatic mind damage (TBI) impacts sleep in mouse fashions of Alzheimer’s illness and the way predation stress has formed the evolution of sleep with a give attention to wild rat populations.


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