Sharks and Dolphins

On a recent trip to Hilton Head my girlfriend and I decided to rent some Jet Skis. There was a short orientation about jet ski safety and after that they gave us the chance to ask some questions. My girlfriend raised her hand and asked if there was any danger of sharks. The guide responded by saying that while we are out in the bay we will see lots of dolphins and that is an indication that no sharks are nearby. Someone asked why and he said that dolphins will ram a shark in the gills and drive it away if it gets to close to them, so sharks naturally stay out of thier water. This sounded like B.S. to me. Whats the straight dope on this issue?

It appears to be true, but rare, and when it does happen, the sharks are usually small. See Topics in Shark Biology.

Found a story dolphins defending a human from sharks that mentions that dolphins have been known to kill sharks in this manner. I also know that sharks will prey on young, injured, or ill dolphins.

OTOH, this site claims that dolphins nearby means a greater chance of sharks due to food scraps left behind by feeding dolphins and the presence of possible sick, injured, or otherwise prey dolphins.

Bear in mind, also, that swimming around a group of wild dolphins is a BAD idea, even if there aren’t any sharks around.

No, dolphins woun’t eat human swimmers, as sharks can, but wild dolphins can be very aggressive and dangerous (young males, especially). I know that there are many resorts and hotels now where tourists get to swim with dolphins, but that does NOT mean wild dolphins are eager to frolic with you.

Wild dolphins can be very territorial, so they often do ram animals that enter their space- that CAN mean sharks, but it can also mean humans!

I’m not trying to demonize dolphins! I love them myself! I just warn you not to think of them as cute, harmless little Flippers!

I wouldn’t rely too heavily on dolphins’ shark-fighting skills.

I remember seeing a documentary a while back about great white sharks in the Mediterranean. Shark experts debating about whether there really were great whites in that sea debated about what they could possibly be eating (the Mediterranean apparently being short on seals, the great white’s usual favorite food).

When a great white was actually caught and killed there, they cut it open. It had a belly full of dolphins.

Dolphin knowledge, not dolphin rumor:

Dolphins usually hang out near the shore where murky water and surf can provide some defense cover, especially the bottle nose dolphins found off the East coast. Often, it is a mild defense habit, and some benefits to hunting fish as well.

Usually, these dolphins are keen on avoiding sharks, and they often have younger dolphins along.

Generally, the dolphin is keener than you are at avoiding predators, or food competitors (more likely the shark is competition for food, or could scare food away)…so, having dolphins around is sort of comforting, but when with their young, they can be dangerous and aggressive.

I would not be getting the warm and fuzzy feeling that dolphins are these great shark bashers, pushing aroung the tough guys and indirectly bonding with their human brothers.

Having spent many years on the Atlantic, I would never jump in with wild dolphins, because there is absolutley NO BENEFIT TO YOU IF YOU JUMP IN, but there is a chance that you might irritate them.

On a Jet Ski, you are fairly safe since sharks attack out of mistaken identity or delusion. Sick sharks in shallow water will attack something that doesn’t even look like it’s prey, while most tigers, whites and man-eaters attack man that looks like it’s common prey.

On a Jet ski, you don’t usually look like their common prey.

Please note themy use of disclaimers words: usually, chance, fairly, might, sort of…

:::I remember seeing a documentary a while back about great white sharks in the Mediterranean. Shark experts debating about whether there really were great whites in that sea debated about what they could possibly be eating (the Mediterranean apparently being short on seals, the great white’s usual favorite food).

When a great white was actually caught and killed there, they cut it open. It had a belly full of dolphins.:::

Well, they’re not called ‘great’ for nothing. Great Whites are very large, and very aggressive. A full grown one is certainly much larger than a dolphin. However, many species of shark are much smaller than dolphins, but certainly large enough to be a threat to humans.

Keepin mind that dolphins are not some altruistic creature that’s on the look out to save humans. In fact, if I was a dolphin, I’d be pretty miffed at humans for leaking oil into the ocean, racing around in motor boats, making movies like Free Willy II, etc. Still, sharks are not much of a threat to humans, and if you’re worried about getting bit (and, after seeing Jaws, who isn’t?) you should realize that you’ve got a better shot of getting hit by a car than of getting attacked by a shark.

In the ocean?:slight_smile:

Lure, haven’t you seen those SUV commercials with the vehicle being attacked by sharks? :smiley:

Yeah, the odds of being bitten by a shark might be 2,000,000 to 1, but those odds go up in shark infested waters!