Dolphins and the Coriolis Effect

For some reason, all the sick or injured dolphins at the Cetacean Hospital where I seem to swim Counter-Clockwise in their round tanks. After a while, they’ll get curved from this. We have to excersise them daily (isometrics) in an attempt to keep all the muscles and tendons stimulated and prevent their bodies from tightening up on one side.
When they are fed, much effort is made in an attempt to force the dolphin into right turns by throwing the fish to that side. I guess it’s better than nothing.

I have a theory (look at Bear getting all scientific n shit), that maybe they are swimming that direction because of the current in the tank. I believe that Cecil’s article on the coriolis effect explains that it has little impact on small systems like toilets and quarter million gallon dolphin pools. What does make the difference is that a small current is created depending on how the container is filled. Even if extemely slight, the water molecules continue to move in little current. And when the thing is drained, this current is multiplied and it all drains that direction. Or something… But I believe that even though the water looks calm before he goes in, there is always a slight current.

I’m wondering if the dolphin can feel the current and swims that direction instinctively. Then his swimming naturally increases the current in the pool to the point where it would be silly for him to turn around. After all, he’s sick or hurt - why swim against a current. There is a noticeable current in the pool from the dolphin swimming counter-clockwise non stop. But that doesn’t explain why they choose to swim that direction in the first place.

Since we’re on a budget, and an intricate jacuzzi jet system is out of the question, couldn’t a half dozen people walking in the pool change the current? How hard would it be to get the water spinning the other way? The water in the pool is lowered to below nipple level when we go in to work on the animal. So we wouldn’t be fighting all 250,000 gallons. We’re usually in there for about an hour while we tend to wounds, draw blood, sweep the tank etc.

I can’t help but think that while people are holding the dolphin, there should be others in there trying to reverse the current in the pool. Once everything is going clock-wise, we could spin him to face that direction a-la ‘Pin the Tail on the Donkey’ style and he would start swimming clockwise with the current. That way he alternates which direction he’s going and gets a better overall work-out. And the risk of getting curved is greatly reduced! Or am I an idiot?

Do you think he would swim with the current? I don’t see why he wouldn’t.

Do you think a couple people could effectively change the current in a pool like that? I’m just about positve we could. As a kid, it only took three of us walking around a round pool to stir up a really good current!

Or do you think that maybe the dolphins just like going that direction. Do dolphins swim clockwise in the Southern Hemisphere :wink:

Is this at least good enough to approach the head biologist or doctor with? After all, I’m just a little ole medic volunteering my time to help the fishies. I don’t want to look like an idiot by coming to him with some zany plan. So I’m running it by all you geniuses first.

sorry, this thread has GQ and GD elements as well as MPSIMS. I have no idea where it should go. But since I’m sharing my mundane little idea, I’m putting it here

first line =

“For some reason, all the sick or injured dolphins at the Cetacean Hospital where I WORK seem to swim Counter-Clockwise in their round tanks.”

Damn… even after proof reading. Sorry, I had to correct this or you might think *I seem to swim Counter-Clockwise…

Dan Marino’s arm wasn’t that good.

Since this is MPSIMS and not GQ, I feel free to talk out of my ass.

I think the likelihood of these dolphins being affected by the Coriolis effect is extremely small. Other things like wind, the flexibility of the tank walls and the location of drains or other irregularities must have a much greater effect on the way the water flows than the Coriolis effect.

It seems more likely that the dolphins just like having the wall on the same side of them all the time. Or possibly the water is warmer on one side of the tank. Maybe you could ask some people at other dolphin tanks if they’ve noticed the same thing. If it turns out to be a widespread phenomenon, you might be able to get rich by inventing a donut-shaped dolphin tank.

Two people holding a door or something similar between them could certainly change the current, at least for a little while. Even if it fails, it’ll probably be a good workout.

My own crackpot theory is that the dolphins suffer from dog on a cage syndrome. That’s where a dog in an enclosure will keep walking around in one direction over and over and over.

I know squat about dolphins.

But I suspect your whole concept about swimming with or against a current is probably meaningless.

Current, whether a circular current in a tank, or a linear current in an ocean, merely describe the difference between the animal’s progress rlaltive to the surrounding water versus relative to the fixed earth.

It’s just was easy to swim through the water at 10 mph against a current as with a current. The only difference is how fast you’re traveling relative to the tank/sea floor. In a 5 mph current you’re either going 5 or 15 mph versus the tank/sea floor. But either way you’re expending exactly the same effort / calories to go 10mph versus the water.

For a boat on a schedule, you try to make a certain speed relative to the bottom, and hence have to go faster / burn more fuel going against the current. But dolphins, particluarly those in tanks, probably aren’t trying to keep a certain speed versus the bottom.
I’d suspect the cause is more social. A tank, even a large one, is tiny by comparison to their normal habitat. Think of human in a jail cell (or trapped in a small, but cushy apartment if you’d like to avoid the whole PETA imagery.)

In the wild the animals form small groups which swim together generally in the same direction. That’s how they stay together, by definition. How often would a dolphin in the wild encounter another one going the opposite direction? Rarely, if ever.

So I suspect that once they start swimming, there’s a strong social incentive for the next one to join the herd, and to join it they have to swim in the same direction. And so the direction self-reinforces.

Do they ever all stop swimming, so there is no established direction? I don’t know if dolphons sleep or how they do it, or if you occasionally separate them all into pens.

But if the circular swimming is ever totally stopped, then I’d expect they be as likely to go the other way next time. At least I’d expect that if they were totally stupid aminals like sheep or snails.

Obviously dolphins are NOT totally stupid animals like sheep or snails. So even if they do all stop swimming on occasion, when it comes time to start again, they have memories.

Where there are glass double doors (such as the entrance to a large store), do you go through the right one even when you can see nobody’s coming the other way? Probably (at least in the areas where folks drive on the right.) Why? Social habit. You might even refrain from belching at the table, even when dining alone. Why? Social habit.

Dolphins presumably have social habits too, and your crowd has apparently learned “Around here, we swim counterclockwise.” It’s a simple convention that reduces social friction. I imagine that in dolphin society, crashing into someone coming the other way is considered a social gaffe.

Good points all around!

LSLGuy, each dolphin has his/her own tank. When they get healthy and close to release time, they swim all directions. We will even fill the tank as deep as possible to give them more room to dive and such. The healthy ones will swim any way they want. They play with their toys and just swim about as they please. Sometimes they swim in circles, but the circles are interupted by random swimming across the tank or whatever.

But when the animals first arrive, when they are really sick or injured, they swim very slowly (if at all) and in one direction. The circles start off rather small and gradually grow to the full circumference of the tank.

I understand what you’re saying about swimming against a current not really mattering much if he doesn’t have a deadline to keep. But consider this, if we created a 8 mph current in the pool and the dolphin at a slow swim is only pushing 5 mph, he’d be working his ass off and going backwards! Would it not matter much to him that he’s going backwards? I’m thinking that he would choose the direction that is easiest to travel…

hyperelastic, I am starting to picture a donut shaped tank with jets going in either direction so one could control the direction and speed of the current… I could be rich!

Alright, my pointless thoughts on this subject. My initial suspicion is that the dolphin’s direction is more likely habit. than anything else.

Secondly, you said there was a noticeable current in the tank after the dolphins have been in for a while. In the same direction as the swimming?

For a dolphin (or anything else) to move forward it has to push water backwards. As the dolphins slow down from friction with the water, they will counteract the initial backwards push to some extent.

Last thought. The easiest way to push water in the other direction might be something like an outboard engine. (electric if you can rig it, keep those nasty gas fumes out of the tank)

An engine would be easy for us to rig up, but not easy on the dolphins. The sound of the engine constantly hammering into the water would drive them crazy. Just look into the problem of the river dolphins (baiji? dolphins) of the Yangtze, and how they are being driven out of their habitat by the constant and confined sound of engines.

It would be a solution similar to having dolphins outfit our houses with jackhammers so we never have to dust again.

Most of the noise from an outboard comes from the internal combustion engine. If you could isolate the electric motor from the blades (long shaft?) it may be very quiet.

Are you suggesting that a counter-clockwise swimming dolphin should create a clockwise current because that’s the direction he’s pushing the water? Could you elaborate.

Easy, sure. But that engine would send his stress levels through the roof. :wink:

(On Preview) Ahhhh a “quiet” engine… I see. It would also need a cage around the propelor. Wouldn’t want any accidents.

I don’t think it’s the currents in the tank, but more of a matter of boredom, much like a smart dog in a cage…or even a back yard. I’ve a dog that used to run figure-8’s in my back yard so much that there ended up being a packed-dirt “track” in my back yard.

A friend of mine is actually a dolphin trainer at the clearwater marine aquarium, PM me if you’d like to contact her.

I’m not so sure it would be habbit but ease of stroke. As a swimmer I can tell you that one arm is stronger then the other and sometimes I have to fight to keep in a straight line. My backstroke is pretty bad because I drift to the left pretty easy. I would say that if an animal was sick or weak then it wouldn’t care if it was swimming the same way all the time.

As for pushing backwards to swim, no you don’t. A dolphin kick is an up and down kick and the water is pushed more down then behind. I’m pretty sure dolphins mostly “kick” with their tails then anything, though I don’t know that much about them.

If they pushed water mostly down, then they would move up. As my old dad used to say “For each action there is an equal and opposite reaction”. You wanna move forward, you gotta push water backwards (one way or another).

FTR, a dolphins’s thrust comes from his tale and flukes (rear flipper) only. His side flippers are for steering, and his dorsal fin is pretty much useless. But it looks nice ; ) It looks like it would help with stabilization or something, but many whales and dolphins lack a dorsal fin.

Dan Turk, I believe Clearwater sends all their hurt or sick dolphins to us. If he/she is a trainor then her main experience is with healthy dolphins, right? Regardless, I would like you to show her this thread and have her email a response to me. If you wouldn’t mind. Maybe he has an anecdote to add or something. Thanks!