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Tuna use sharks as back scratchers despite risk of being eaten

newscientist.com

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Re: Tuna use sharks as back scratchers despite risk of being eaten

#31

Post by gerdesj »

NLPlatypus wrote: post #28
gerdesj wrote: post #27

Earlier quoted context omitted.

Seabed, rocks etc.

Ok but that’s far away. What’s next, not carrying all the groceries in one trip?

That's why they risk rubbing themselves on a mincing machine.

I subscribe to New Scientist (actually Dad is currently) and have done so for roughly 35 years. This is not the finest science ever reported.

There will actually be loads of really great science and stuff from these studies but sadly "tuna shags shark" or some other rubbish sells ads n that.

I'm starting to get a bit disillusioned now and might have to pen an "angry of Andover" piece to NS. I'll threaten to cease my subscription (that my dad pays for) and look like a right old prat.

On the other hand, I might simply ask for some decent science. This isn't the best. It sounds novel to start with but rapidly looks like tosh.

Re: Tuna use sharks as back scratchers despite risk of being eaten

#32

Post by jsjohnst »

telman17 wrote: post #18
unaindz wrote: post #13

Earlier quoted context omitted.

I do scuba diving as a hobby and I have touched a few sharks. Every one of them had rough skin, just like sandpaper actually.

Yikes! That would terrify me. Do the sharks seem bothered by it?

I’m also a scuba diver and have also touched sharks while diving. They reacted in a similar way to a dolphin or a seal or any other large aquatic animal, as in it all depends on how they are touched. If it’s a gentle “pet”, they don’t seem to mind. If you punched, poked, yanked, or some other aggressive action, then the response would be different. Also note, there’s many types of sharks and not surprisingly, some more aggressive than others. I can’t speak for GP, but I’ve never touched a bull/tiger/mako shark, let alone a great white.

Re: Tuna use sharks as back scratchers despite risk of being eaten

#33

Post by Ancalagon »

I guess "keep your friends close and your enemies closer" has never been more applicable. Such a strange behavior its hard to see the reasoning. Aren't tunas supposed to be semi-intelligent, as far as fish go? I feel like I remember seeing something like that before?

Re: Tuna use sharks as back scratchers despite risk of being eaten

#34

Post by 2-718-281-828 »

andyjsong wrote: post #23

I wonder how many years of evolution it took for tunas to target the back end of a shark instead of the front. And how many more years it will take before tunas can grow fingernails and scratch their own parasites off?

> I wonder how many years of evolution it took for tunas to target the back end of a shark instead of the front.

I would not be surprised if they can think and learn by observation. Then there would be no need for evolution.

Re: Tuna use sharks as back scratchers despite risk of being eaten

#35

Post by Retric »

gerdesj wrote: post #15

A tuna is a seriously fast fish. Note that they rub at the back end of the shark, which is the obvious place to go. If the shark gets annoyed the tuna can get away rapidly and get a very decent head start before the shark has turned and got going. The sharks are probably not bothered about being used for grooming because it is reassuring to have your lunch check in and say hi occasionally. 6,000 camera deployments of…

I don’t know that adult tuna are at much risk from these sharks. Not only are the tuna much faster, but both species are predictors of roughly the same weight with the sharks tending to be smaller and both preferring to hunt smaller fish.

Younger or weak specimens could be, but yellowfin tuna presumably also occasionally chow down on significantly smaller sharks.

Re: Tuna use sharks as back scratchers despite risk of being eaten

#37

Post by w-ll »

Retric wrote: post #35
gerdesj wrote: post #15

A tuna is a seriously fast fish. Note that they rub at the back end of the shark, which is the obvious place to go. If the shark gets annoyed the tuna can get away rapidly and get a very decent head start before the shark has turned and got going. The sharks are probably not bothered about being used for grooming because it is reassuring to have your lunch check in and say hi occasionally. 6,000 camera deployments of…

I don’t know that adult tuna are at much risk from these sharks. Not only are the tuna much faster, but both species are predictors of roughly the same weight with the sharks tending to be smaller and both preferring to hunt smaller fish. Younger or weak specimens could be, but yellowfin tuna presumably also occasionally chow down on significantly smaller sharks.

Tuna, Turnips, Trek

Re: Tuna use sharks as back scratchers despite risk of being eaten

#38

Post by User23 »

gerdesj wrote: post #15

A tuna is a seriously fast fish. Note that they rub at the back end of the shark, which is the obvious place to go. If the shark gets annoyed the tuna can get away rapidly and get a very decent head start before the shark has turned and got going. The sharks are probably not bothered about being used for grooming because it is reassuring to have your lunch check in and say hi occasionally. 6,000 camera deployments of…

If you have the opportunity I strongly recommend visiting the Tuna tank at the Monterey Bay Aquarium during a feeding. Watching a fish the size of a VW Beetle swim 30 kilometers an hour is incredible.

Re: Tuna use sharks as back scratchers despite risk of being eaten

#39

Post by discordance »

Hamuko wrote: post #7

There's all sorts of weird relationships between sharks and other fish. Like the fish that live off by performing dentistry for sharks inside their mouths. https://www.youtube.com/watch?v=V5EszU8yuA8

Amazing! The evolutionary pathway of the sharks that didn't chomp and the Cleaner Wrasse that had the guts (or the lack of flight response?) to go near a sharks mouth is astonishing.
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