Tonic Immobility on Sharks

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In this picture I am taking length measurements (left), Cristina is immobilizing the shark (right) and Tom (middle) is taking a break. Picture by Never Ready Eddie.

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One year ago I became fascinated with tonic immobility on sharks from my first sight of it in a National Geographic documental. It was about an italian girl who has spent at least the last 10 years doing this to Reef Sharks in the waters around Freeport, Grand Bahama.
Tonic immobility, also known as animal hypnosis, is a natural state of paralysis that some animal species enter by differents stimulations and reasons. It has been observed in some elasmobrachs in natural state and it can be induced by humans in two different ways. The first one is by turning the animal upside down (it can remain in this state for up to 15 minutes). The other way is by “stroking” their nose using the fingers with a very particular technique.
One year ago I became fascinated with tonic immobility on sharks from my first sight of it in a National Geographic documental. It was about an italian girl who has spent at least the last 10 years doing this to Reef Sharks in the waters around Freeport, Grand Bahama.
Cristina Zenato is the first female shark feeder and one of the world’s leading experts on tonic immobility in sharks. I had the opportunity to dive with her -and with her sharks- and it was interesting enough and absolutely incredible. She is a very special person, concerned about the protection and conservation of the shark population she works daily with. That’s why she asked me to take DNA samples to do some useful research and to standardize the data sample for the next dives!

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In this picture I am taking length measurements (left), Cristina is immobilizing the shark (right) and Tom (middle) is taking a break. Picture by Eddy Raphael