Some sharks can never stop moving. Scientists just figured out how they rest.

·1 min read
Some sharks can never stop moving. Scientists just figured out how they rest.
Some sharks can never stop moving. Scientists just figured out how they rest.

Some shark species must constantly move to ensure enough oxygen is extracted from their gills to keep them alive.

But that begs the question: How do sharks rest?

Researchers at the Florida International University believe they've found the answer. The marine biologists were studying grey reef sharks in French Polynesia when, during a dive, they noticed sharks were positioning themselves on updraft currents and using them to 'surf'.

This act keeps their muscle movements at a minimum, allowing them to rest.

The sharks observed in the study were taking turns using the current as a sort of conveyor belt. As they moved along a current in a channel, they would slip backward once they reached the front, allowing the current to carry them back to the starting point.

Researchers used several tools to confirm their findings, including underwater cameras and a biomechanical model used to calculate the sharks' energy expenditure when using the currents.

They found that surfing the updraft helps sharks conserve about 15 per cent of their usual energy expenditure.

It appears to be common practice: When searching other sites, the researchers found sharks tend to congregate in areas where updraft currents are strong, and now they know why.

The findings are published in the Journal of Animal Ecology.

Thumbnail image: Kelvin Gorospe/NOAA/Flickr CC BY 2.0.

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