Surprising discovery challenges long-held beliefs about shark physiology
Contrary to long-standing beliefs, recent research has revealed that grey reef sharks can rest, overturning the assumption that they must constantly swim to breathe. This groundbreaking discovery, made in the Seychelles, offers new insights into the physiology and behaviour of these marine predators.
Grey reef sharks are classified as obligate ram ventilators, believed to require perpetual motion to force water over their gills for respiration.
However, researchers observed these sharks resting under coral reef ledges, indicating a shift from ram ventilation to buccal pumping, a method allowing them to breathe while stationary, which was previously thought to be impossible for this species. This adaptation is significant, as it indicates a more complex and versatile physiology than previously recognised.
This discovery has profound implications for future shark research, particularly studies on metabolic rates, energetics and behavioural strategies. Understanding that these sharks can rest alters assumptions about their energy expenditure and ecological roles. It also raises questions about the resting and potential sleeping patterns of other shark species, especially those considered obligate ram ventilators.