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Post by Life on Dec 23, 2017 11:06:10 GMT 5
Looks like some (adult) great white sharks are experimenting with big-game hunting.
Human activity has unfortunately affected the flourishing of great white sharks to a large extent, thanks in part to the movie JAWS and other forms of propaganda.
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Post by elosha11 on Dec 23, 2017 23:04:01 GMT 5
Here's an interesting video of a mako preying on a dolphin. What's "interesting" about it is if you compare the mako size to the dolphin (the half that's left) you can see there's little difference in size. If anything the dolphin might be larger than this relatively slender mako. Yet what looks like nothing more than an average size mako, had the power/jaw strength to bite the dolphin in half quite close to the middle of its body. I think people think that because makos teeth are more slender than those of the great white that they are only fish eaters and lack requisite cutting ability and bite force necessary for hunting large mammalian prey.
There are other videos I could post of mako/dolphin and mako/pinniped predation. Suffice it to say, I think makos are a real threat to dolphins in the Atlantic, maybe even more than great whites, tigers, or bull sharks. The main reason is their incredible speed. As fast and agile as dolphins are, they often can't outrun a determined mako.
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Post by elosha11 on Aug 17, 2018 19:55:06 GMT 5
Pretty incredible footage from South Australia showing the damage a great white can do to a cetacean. Obviously big difference in body size but that bite damage is still incredibly impressive. "Mother Nature worked her magic this morning and put on a dramatic show in front of shocked workers three kilometres off Smoky Bay at the towns local Oyster leases. The incident involving two Great White sharks ended in fatal circumstances for a Dolphin which was attacked and then once killed the devoured carcass dragged away in front of their boat as viewed here [Image: 1f92d.png]? - footage by Jason Darke." www.facebook.com/sharkalertsa/videos/254811515233179/Edit - can't get the video to embed but this link will take you there. And a couple images just in case the link gets deleted later on.   |
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Post by elosha11 on Aug 22, 2018 20:02:35 GMT 5
Here's the full video of the great white predation on the dolphin in the above post.
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Post by elosha11 on Mar 19, 2019 20:18:58 GMT 5
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Post by DonaldCengXiongAzuma on Mar 28, 2019 4:49:48 GMT 5
 source→Juvenile dolphin, bitten by shark. Presumably a great white, guesstimated at ~3m in lenght. A dolphin that survived a large shark bite wound on its back. This list→ contains three cases of large great white sharks whose stomach contents included dolphins of various states of maturity, but all of course much smaller than the shark, considering the complete dolphins were swallowed. There’s this account of a 3.8m long false killer whale→ succumbing to injuries sustained from a shark bite, however no data on the size and identity of the culprit or much detain on the bite anatomy. It’s a save bet that false killer whales, social habits, reportedly agressive behaviour and formidable jaws (morphologically and proportionately comparable to a those of Orcinus), are not usual prey to any shark of similar size, which would make shark predation on them a fairly rare event since they themselves are close in size to the largest macropredaceous shark species. Also Pseudorca is very poorly studied and its exact ecological role and predatory capabilities remain to be further examined. On the other hand, it’s well known that orcas can and do predate various species of shark→, including great whites: www.youtube.com/watch?feature=player_embedded&v=W8GaDuCvYbEwww.prbo.org/cms/docs/marine/MMS.pdfThere are also the accounts of smaller dolphins that were already posted. Also, not strictly a confrontation (the video title is plain ridiculous), but here some dolphins approach a hammerhead shark without fear: It seems sharks and dolphins kill each other, but mainly if they are at a considerable size difference. At least, I found no compelling account of a dolphin killing a comparable-sized shark or vice versa, even though both have the theorethical (i.e. anatomical) capability to do so. From what I’ve read, they leave each other alone at similar sizes. i feel sorry for the juvenile striped dolphin. That is one of my favourite cetacean. |
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Post by sam1 on Mar 28, 2019 13:49:30 GMT 5
Here's an interesting video of a mako preying on a dolphin. What's "interesting" about it is if you compare the mako size to the dolphin (the half that's left) you can see there's little difference in size. If anything the dolphin might be larger than this relatively slender mako. Yet what looks like nothing more than an average size mako, had the power/jaw strength to bite the dolphin in half quite close to the middle of its body. I think people think that because makos teeth are more slender than those of the great white that they are only fish eaters and lack requisite cutting ability and bite force necessary for hunting large mammalian prey. There are other videos I could post of mako/dolphin and mako/pinniped predation. Suffice it to say, I think makos are a real threat to dolphins in the Atlantic, maybe even more than great whites, tigers, or bull sharks. The main reason is their incredible speed. As fast and agile as dolphins are, they often can't outrun a determined mako. Makos are easily the most impressive sharks to me. Their physical abilities combined with intelligence make for a freakishly formidable beast. As for this video though, there's obviously a lot of unknowns so it can't be taken for granted. It shows mako feeding on a dead dolphin. It doesn't show the conditions leading to that outcome. What is sure though is that mako did not bite through the dolphin like that outright..the lack of blood and the missing half of body means the shark was devouring it for quite some time. |
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Post by elosha11 on Apr 10, 2019 23:35:35 GMT 5
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Post by elosha11 on Apr 10, 2019 23:45:25 GMT 5
Here's an interesting video of a mako preying on a dolphin. What's "interesting" about it is if you compare the mako size to the dolphin (the half that's left) you can see there's little difference in size. If anything the dolphin might be larger than this relatively slender mako. Yet what looks like nothing more than an average size mako, had the power/jaw strength to bite the dolphin in half quite close to the middle of its body. I think people think that because makos teeth are more slender than those of the great white that they are only fish eaters and lack requisite cutting ability and bite force necessary for hunting large mammalian prey. There are other videos I could post of mako/dolphin and mako/pinniped predation. Suffice it to say, I think makos are a real threat to dolphins in the Atlantic, maybe even more than great whites, tigers, or bull sharks. The main reason is their incredible speed. As fast and agile as dolphins are, they often can't outrun a determined mako. Makos are easily the most impressive sharks to me. Their physical abilities combined with intelligence make for a freakishly formidable beast. As for this video though, there's obviously a lot of unknowns so it can't be taken for granted. It shows mako feeding on a dead dolphin. It doesn't show the conditions leading to that outcome. What is sure though is that mako did not bite through the dolphin like that outright..the lack of blood and the missing half of body means the shark was devouring it for quite some time. Good observations. The lack of blood in the water certainly seems indicative of a prolonged feeding. And as you note, we don't know the condition of the dolphin prior to what was presumably an attack. Still, there are quite a few videos of makos preying on dolphins and purpoises, indicating the shark is a danger to smaller and similar size cetaceans. As you correctly note, the shark may very well have bitten off the lower half of the dolphin with a series of bites after the initial attack, rather than in one fatal bite. But I still wouldn't be surprised if the shark at least bit off the tail in the initial attack. I get the feeling that people think the lack of serrated teeth makes makos' bites not all that bad. However, if you look at the prey they target, big fish (tarpon, sailfish, swordfish), dolphins, and seals, you see they are capable of inflicting horrific damage very quickly. Adult makos teeth become more broad and triangular and more adapted for mammalian prey, which are taken with some degree of regularity, along with large fish. |
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Post by sam1 on Apr 11, 2019 16:34:48 GMT 5
Yeah, no doubt about mako's deadlines..I said they're the most impressive sharks to me anyway. There's no dolphin I would back against a mako 1v1 at parity, mainly because mako's speed, acceleration and turning ratio are so superior that it makes dolphin's superior maneuverability not so much a factor.
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Post by prehistorican on Apr 12, 2019 6:43:52 GMT 5
We all know that orcas generally dominate all sharks. But it's still a comparatively dangerous prey/opponent/competitor, even for the largest delphnid. Here's an article and picture of John Coe, an iconic and large male orca who lives off the coast of Scotland. He's recently been seen with a significant crescent shaped bite out of caudal fin that very clearly suggests a shark bite. No idea which species did this, it's too small for an adult great white shark or another orca, but still a fairly sizeable (and probably painful) wound. Moreover, GWS are not commonly around such cold waters. A large salmon shark perhaps? The article calls it a "shark attack" but I would guess more likely was a defense from predation, which the shark could have still very easily lost, particularly if the whole pod was involved in the hunt. But still, it shows the sharks are not a prey/competitor to be trifled with, even for orcas. www.bbc.com/news/uk-scotland-highlands-islands-30980599
Shark attack suspected on killer whale John CoeA shark has been suspected of biting a chunk out of the tail fluke of a killer whale well-known to whale and dolphin watchers in Scotland. Nicknamed John Coe, the male orca can be indentified by a notch on its dorsal fin. The injury to its tail was spotted during a survey by the Hebridean Whale and Dolphin Trust (HWDT). The trust said consultations with experts suggested that it was "almost certainly" caused by a shark. John Coe is one of a small community of orcas regularly seen off Scotland's west coast. Members of the group have also been spotted at times off Peterhead and Girdleness in Aberdeenshire, Ireland's west coast and off Pembrokeshire in Wales. Image caption John Coe can be identified by a notch on its dorsal fin The group, which is believed to be the UK's only resident population of killer whales, is thought to contain just nine older animals. There are fears that it will eventually die out after becoming isolated from other killer whale populations. In a statement, the trust said: "Notable highlights during 2014 included two separate encounters with what is believed to be the UK's only known resident population of killer whales. "This small, isolated population of orca has never produced offspring since studies began, raising fears that it faces imminent extinction." Image caption A young minke whale was spotted during the recent survey It added: "Evidence of drama emerged when one of the group's males - known as John Coe - was observed with a large area of his tail fluke missing. "Consultations with experts suggest that this was almost certainly the result of a shark attack." The trust said it could not "realistically speculate" on the kind of shark involved. HWDT carried out its latest survey of whales, which included a young minke whale, dolphins, porpoises and plankton-feeding basking sharks, between May and October last year. The trust has now released information on the data it gathered, including a 25% increase in sightings of harbour porpoises and a 33% decline in observations of basking sharks. I've heard that it could have been by a mako and I think it may have been in self defense. |
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Post by elosha11 on Apr 12, 2019 22:03:04 GMT 5
^Yes, there was a follow up article in which some researchers stated it was almost certainly a mako because great whites only rarely frequent these waters, and the bite mark size more closely aligns with a mako shark than with the larger great white, which would have likely left a significantly larger bite mark. Still, I think it does show that if a sizeable shark does bite even a much larger male orca, it's going to do significant damage.
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Post by elosha11 on Apr 14, 2019 0:05:31 GMT 5
Below article found at www.abc.net.au/news/2018-09-11/dolphin-predation-by-sharks-on-the-rise-in-wa/10230370Shark attacks on dolphins on the rise in WA in line with rising ocean temperaturesSep. 10, 2018 The theory that dolphins keep surfers safe from sharks has been blown out of the water with a Western Australian study. Researchers from WA's Murdoch University Cetacean Research Unit monitored dolphin populations off the coast of Bunbury in the state's south west and Shark Bay in the north, and found shark bites increased each year from 2009 to 2013 — in line with rising ocean temperatures. Dolphins in sheltered waters were "significantly" more likely to be bitten than populations in deep coastal waters. The research also saw a spike in attacks over the summer months of 2012–13. Researcher Kate Sprogis said great whites and tiger sharks were believed to be largely responsible for the attacks in Western Australia. "In the case of great whites, for example, once they get beyond a length of about 2.7 metres, they need marine mammals in their diet, so they will shift from fish to predating on seals, sea lions and they will also try for dolphins," Dr Sprogis said.  "We attempted to identify each bite mark, but often they get quite messy as the shark will come in from a side angle. We were able to identify a few that were from tiger sharks if the bite mark was broad, blunt or square." Dr Sprogis said the research also concluded there was little difference when it came to the sex or age of dolphins but lethal bite marks tended to come from "large predatory sharks". "In the two areas the research was carried out, there was a 74 per cent bite rate off Shark Bay while in Bunbury it was 17 per cent," she said. "But that is just the dolphins we do see; many more would have sunk to the bottom so we could not include those that had incurred lethal bites."  La Niña factors into spike Dr Sprogis said the research team had initially hypothesised the incidence of sharks attacking dolphins were unlikely to increase over the years, but between 2007 and 2013 predation increased as ocean temperatures also rose in line with the La Niña weather pattern. "The Leeuwin current was bringing the warmer waters down with it," Dr Sprogis said.
"What we did see was an increase in shark bites on the dolphins. We also think that drew more tiger sharks into the areas with the warmer waters."
Dr Sprogis said there was no available research to indicate dolphins in turn predated on sharks but there was evidence they did "try to escape".
"They will leap out of the water and alert other dolphins of the presence of sharks," Dr Sprogis said.
"But if the water is shallow, they often can't turn quickly enough or they don't acoustically hear or detect sharks in proximity, so it might be harder for them to react and that would be a large reason in why they get bitten."
Dr Sprogis, also a keen surfer, said the research put paid to a long-held theory for surfers relying on the presence of dolphins to deter sharks.
"Growing up, I also thought that every time I saw a dolphin out in the surf everything was fine," she said.
"Seeing these shark bites on dolphins though, I now know sharks do predate on dolphins and you shouldn't rely on that theory when you're out in the surf."
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Post by sam1 on Apr 14, 2019 13:51:10 GMT 5
Damn..those wounds. Dolphins can really take terrible bites and appaarently survive thanks to the thick blubber. The pain of going through that must be agonizing to them though. I'd love to see how on earth the "healed" state of that first wound looks like.
Anyway, I don't see why any of this "blows the theory of dolphin protecting surfers from sharks out of the water".
Firstly, it's not a theory but proven occurrence.
Secondly, the accounts happened in deep water, and it always involved a group of dolphins that were well aware of the shark..entirely different circumstances than targeted ambush predations on single dolphins.
So the quoted conclusion is just very short sighted and plain false.
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Post by sam1 on Apr 14, 2019 13:56:02 GMT 5
..as for the bite on the male orca..well that's an intriguing one.
Perhaps a badly executed "karate chop", or, more likely, some crazy mako taking a bite while the guy was resting.
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