Jobs working with sharks

Andre Hartmann, a South African diving guide can calm down a great white shark:

‘When the shark is next to the boat, I lean over the edge, and wait for it to open its mouth. Sometimes it opens its jaw to the side. This tells you that the shark is trying to work out how to bite the fishy smelling boat, but doesn’t know how to do it. I put fish on the boat, to attract and confuse the shark. Then I take one or two fingers and press them against the shark’s snout for a second.’

‘It’s almost like the shark is hypnotised. The animal goes into this pleasant but confused state, dreamily seeking the source of the stimulus. There is no trigger for the shark to attack anything. I am quite safe. The shark flips on to its back, and drifts harmlessly out to sea.’

‘This is called tonic immobility. The shark’s dorsal fin straightens, and both breathing and muscle contractions become steadier, more relaxed. Sharks only relax for a few moments, though. Give one a playful rub on the tummy, or dangle a bit of fish over its nose and you’ll very likely wake it up.’

A diving putting a shark into Tonic Immobility by Mozcashew1 via Wikki Commons


Tonic Immobility is an unlearned reflex. That means it is something the animal knows how to do automatically, in the same way we instinctively know how to breathe. It causes muscles to relax and the animal’s body to go limp for a period of time. It occurs in a lot of different animals, including insects, amphibians, reptiles, birds, mammals and fish. We don’t know exactly why it happens, but it is certainly useful for shark whisperers like Andre.

Photographer and conservationist Jillian Morris takes photos of sharks, but isn’t scared at all:

‘Sharks are more curious than dangerous. Imagine a new kid comes into your classroom. Would you go check them out? Ask their name? Sharks want to know what we are doing in their world. Are we competition for food? Are we passing through? Scuba divers blow air bubbles when they breathe out and this makes a lot of noise. Sharks want to know what this is.’

‘I don’t bother with protective equipment. Sharks don’t hunt down and attack humans, when we’re on scuba they can be quite timid. We respect their space and do not try to grab or harass the animals. Respecting the shark is my best protection. If we’re feeding them we might wear chain mail suits, so that the sharks don’t mistake hands or feet for bits of fish.’

‘I keep out the way of tiger sharks, though. Tiger sharks can evert their stomachs. (To evert is to turn something inside out.) The stomach hangs out of their mouth like a big red tongue, and if you’re not careful you’ll get covered in fish bones, bird feathers and other stuff the sharks can’t digest. I’ve seen a tiger shark spit up a half-digested sea snake. The smell was horrendous, but it was really cool to see how their system works.’

Albert kok, CC BY-SA 3.0 , via Wikimedia Commons

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Words: The Aquila Team Illustration: Katie Cotter