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"Sharks v Dolphins" - Accounts, Research, & Info.
Topic Started: Jan 12 2012, 12:43 AM (11,514 Views)
DinosaurMichael
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Here's a thread to post any material you have that relates to the relationship between the various species of Dolphins & Sharks.
Hopefully this will be interesting, and also useful for matchups in the Interspecific Section.

Source 1 'elasmo-research.org'

Q: Do dolphins really beat up sharks?

- John
St. Louis, MO

A: Usually not, unless the shark is relatively small.

This notion is based on a much-publicized incident that took place at the Miami Seaquarium in the 1950's. When a Sandbar Shark showed a bit too much interest in the birth of a Bottlenose Dolphin calf, three of the adult male dolphins ganged up on the shark, butting it in the gills and stomach until it died. This 'protective' behavior was cemented in the public's mind by the television series, Flipper, produced in association with the Miami Seaquarium. There is a record of a Bottlenose Dolphin off California killing a two-foot Leopard Shark (Triakis semifasciata), then supporting it at the surface (which raises doubts about tales of dolphins 'rescuing' human swimmers: perhaps balancing an object on the rostrum is merely a dolphin game, devoid of any altruistic motivation).

During the 1960's, the U.S. Navy trained Bottlenose Dolphins to incapacitate large sharks by butting their delicate gill pouches. The dolphins quickly learned to attack Sandbar (Carcharhinus plumbeus), Lemon (Negaprion brevirostris), and Nurse Sharks (Ginglymostoma cirratum), but refused to approach a Bull Shark (Carcharhinus leucas) of similar size and shape. Sandbar, Lemon, and Nurse Sharks are not known to attack dolphins in the wild, but Bull Sharks are. This suggests that dolphins are able to classify sharks as either dangerous or not dangerous — an eminently practical taxonomy.

In the wild, similar-sized dolphins and sharks pretty much leave each other alone. Some 75% of wild dolphins show some degree of shark scarring — and we usually see only the ones that got away. I have pulled dolphin remains from the stomachs of many sharks over the years, particularly from Tiger Sharks (Galeocerdo cuvier). Thus, it seems that in most battles between dolphins and sharks in the wild, dolphins get the worst of the encounter.
http://www.elasmo-research.org/education/topics/b_corner.htm

Seems they are suggesting the aggressive shark species hold dominance over dolphins.

Source 2 What are the natural predators of dolphins?

Large sharks and killer whales are the only natural predators of dolphins. Tiger sharks, bull sharks, and great white sharks are the main species that attack dolphins. Humans have also posed a major threat to dolphins in recent years(in Japan the dolphin population was almost completely dessimated during the 1980's and 1990's).Predation risk may have been an important factor that led to the evolution of group living in dolphins. Furthermore, risk of shark predation appears to influence both habitat use and group sizes of dolphins in a variety of locations. In Sarasota Florida 31% of bottlenose dolphins bear bite scars while 36.6% of bottlenose dolphins in Moreton Bay Australia bear bite scars. These are very significant numbers, and could have easily spawned a group defense system among dolphin populations. Interestingly enough, Heithaus and Lawrence found that coastal dolphins exhibited more bite scars than pelagic dolphins. This seems to contradict theories that coastal dolphins remain safer from predators because of the shallow water. Also, few age and sex differences were noted in scarring rates. This implies that all dolphins are equally vulnerable to attack. Some scientists believe that shark attacks on dolphins are simply acts of aggressive behavior because dolphins and sharks utilize the same food sources. This has not been proven however, and more conclusive research needs to be carried out (Heithaus and Dill, 2002).

http://www.bio.davidson.edu/people/vecas....20predators.htm

Seems to back up the main points of the first source, but also highlights that shark attacks on dolphins is not rare.

More on the frwequency in this source -

Source 3 Natural Predators

Besides habitat destruction, pollution, and over-fishing, bottlenose dolphins are threatened by a few natural predators, most notably sharks. Recent studies show that several species of sharks, including the great white, tiger, and mako, attack and prey on bottlenose dolphins. In Western Australia, where extensive studies of dolphin-shark interactions have been conducted, as many as 70 percent of dolphins bear shark-attack scars, and an estimated 15 percent of the population may be attacked each year. The exact mortality rate from shark attack is unknown. The risk of shark predation may have been an important factor leading to the evolution of group living (for protection) in bottlenose dolphins.

More than 30 percent of Sarasota Bay’s bottlenose dolphins have visible shark attack scars, and seasonal population movements correlate with the abundance of sharks: Dolphins tend to move out of areas where sharks are abundant. In the presence of a shark, dolphin anti-predator behavior varies with the circumstances. Some simply swim away from the shark, others ram or bite it, and yet others launch coordinated group attacks to drive the predators away.

http://nationalzoo.si.edu/ConservationAn....eproduction.cfm

Source 4 Q: Is it true that where there are dolphins there are no sharks?

A. No, this is a fallacy. Although dolphins and sharks do not seek each
other to attack, they appear to have a mutual respect. Normally, a shark
will only attack a lone dolphin, a sick dolphin or a calf that strays from
its mother. In Port Phillip Bay, the large male dolphins that usually live
outside the bay come inside at the beginning of October, which is the same
time that the bronze whaler sharks come into the bay to mate and give
birth. Male dolphins form a guard around the females and young to protect
them during this time. Sharks usually keep their distance from the
dolphins.

Bronze whaler sharks are small, but aggressive. An adult Great White Shark
is about 5-7 times bigger, longer and scarier than a bronze whaler. In
fact, a small dolphin would fit between its jaws without touching the
teeth! However, Great Whites like eating seals, which are much easier to
detect, catch and according to new science, they prefer the taste (even
over humans!). I doubt there would ever be a scenario when an adult Great
White attacked a healthy pod of adult dolphins. Sharks are very wary
animals and unlikely to approach a pod that is guarding young.
http://www.madsci.org/posts/archives/2000-08/967564399.Zo.r.html

This source indicates again that smaller but aggressive shark species like the Bronze Whaler can be repelled by large male dolphins in a 'group defence'.

Source 5 - Evidence of predation by a tiger shark (Galeocerdo cuvier) on a spotted dolphin (Stenella attenuata) of O*ahu, Hawai*i

Witness accounts of shark predation on cetaceans
are rare.
Heithaus (2001b) recently reviewed predator-prey
and competitive interactions between sharks and
dolphins. Much of the evidence of shark/cetacean
interaction relies on stomach content studies (Bell &
Nichols, 1921; CliV & Dudley, 1991; Simpfendorfer
et al., 2001), on observations of scarring patterns
and wounds on live dolphins (Corkeron et al., 1987;
Cockcroft et al., 1989; Cockcroft, 1991; Bearzi
et al., 1997; Urian et al., 1998; Heithaus, 2001a) or
on carcasses beached or floating at sea, which often
bear signs of shark predation. However, in some
cases, these animals could have died of other causes
and may have been scavenged after death (Carey
et al., 1982; Long & Jones, 1996; Heithaus, 2001b).

The strategy used by the tiger shark during the
attack seems to confirm previous observations that
successful attacks on cetaceans occur more frequently
from the side/rear, while the higher incidence
of wounds and scars on the back/frontal
regions of the body of survivors indicates this is a
less eVective site of attack (Heithaus, 2001a). In the
case reported, the severing of the tailstock eVectively
ensured the immobilization of the victim,
which was left unable to escape. Interestingly,
another published report of a tiger shark attack on
a bottlenose dolphin (Tursiops truncatus) calf at
Monkey Mia, Australia showed a photograph of
the dead calf with a severed tail: witnesses to the
attack suspect the tail was severed before the shark
took a second fatal bite into the belly of the animal
(Mann & Barnett, 1999). Other observations
also support the hypothesis that many attacks on
odontocetes are directed to the tail (Arnold, 1972;
Cockcroft, 1991; Long & Jones, 1996).
If successful attacks are generally as quick and
flawless as the one witnessed in Hawaiian waters,
it is not surprising they are missed by potential
observers. To date, the rate of shark attacks on
cetaceans is unknown. Inferences on attack rates
can be made from unsuccessful attempts based on
wounds and scars (Cockcroft et al., 1989; Heithaus,
2001a). Nonetheless, lack of scars in a cetacean
population is not necessarily an indication of a low
rate of predation, but a possible indication of a
higher success rate of the predator, since wounded
dolphins only represent misses.
Irvine et al. (1973) reported that between 20 and
50% of bottlenose dolphins living along the shallow
waters of Florida and Texas bear scars inflicted by
sharks.
Sharks, on the other hand, rely on chemical,
electrical and visual cues to find their prey. Their
success in killing a dolphin may depend on opportunity
and speed. Norris et al. (1994) present a
report by Springer, which illustrates a possible
cooperative eVort by sharks to kill a common
dolphin (Delphinus delphis) by surrounding a school
for several hours and flanking the dolphins until an
opportunity is provided. It is common in the open
ocean to find multi-species aggregation where
sharks and dolphins all follow large schooling fish
(Au, 1991). The continued presence of sharks
around dolphin schools may provide many opportunities
for predation although cetaceans do not
appear to be the main staple of any shark species
(Heithaus, 2001b)."
http://www.alaskasealife.org/New/Contribute/pdf/Maldini_2003.pdf

Well this source indicates, even though it was only a juvenile dolphin and the shark must have been quite larger, that their attacks can quick and efficient.

The good news is for dolphins, as evidenced by the number of living dolphins with shark attack scars, is the heal quickly and not al attacks are fatal.

Source 6 - Report on the healing of a large woundin a Bottlenose Dolphin Tursiops truncatus
THERE are several reports that dolphins (Delphinidae) sustain injuries from shark bites (Corkeron et al. 1987a) and that these wounds heal rapidly (Corkeron et al. 1987b; Bruce-Allen and Geraci 1985).
On 20 May 1993 a mature male Bottlenose Dolphin, “Freddy”, arrived at the feeding witha large open wound located on his left side,above and approximately level with the flipper(see Fig. 1). This injury must have occurred during the previous 24 hours since the dolphin had attended the feeding session on 19 May1993 and did not have the wound then. The lesion was roughly semi-circular in shape and approximately 45 cm in diameter. It penetrated approximately 3 cm into the dolphin’s blubber layer at the deepest point, and in two placesmuscle tissue was visible. The wound wasdeepest on the dorsal side, and several punctures resembling teeth marks were presenton its ventral aspect. The shape and type of injury was consistent with a shark bite. Previous research indicates that over a third of all dolphins in Moreton Bay have evidence of sharkbites (Corkeron et al. 1987b)."

http://www.dolphinisland.com.au/dolphinweb/research/papers/paper4.pdf

The dolphin, lived indicating their hardiness and why so many living dolphins bear scars.

Comments?


--------------------------------------------------------------------------------
Re: "Sharks v Dolphins" - Accounts, Research, & In
Post by taipan on Feb 1, 2008, 8:22am

Shark v Dolphin Comparison from Oregon Coast Aquarium

Evolution
Modern dolphins have been around for 12-15 million years and whales for over 50 million. Sharks have been prowling the world's oceans over 400 million years, making dolphins a bunch of flipper-come-latelys.
Advantage: Sharks

Habitats
Dolphins live in open water, near- and offshore, in cool polar waters and warm tropical seas, even in freshwater rivers. Sharks can be found in all these habitats and in the deep sea to at least 10,000 feet.
Advantage: Even

Skeleton
Dolphin skeletons are made of run-of-the-mill, stiff, heavy, boring old bone. Shark skeletons are made of flexible and fascinating cartilage. Shark skeletons are lighter, more flexible, strong where they need to be and heal very quickly.
Advantage: Sharks

Breathing in the Ocean
A dolphin's nostrils are located on the top of its head. This "blowhole" makes it very easy to get a breath at the surface. But what a pain! Go the surface every time you need to breathe?! Sharks just breathe the water.
Advantage: Sharks

Teeth
Most dolphins have conical, daggerlike teeth for grasping prey. The Franscicana dolphin may have up to 240 teeth. A single shark, however, may have several thousand. Shark teeth vary in shape according to what they eat.
Advantage: Sharks

Senses
Dolphins are big on sound and have good eyesight but absolutely no sense of smell. Sharks are all about smell. But their noses are just one facet of possibly the most impressive array of senses in the entire animal kingdom.
Advantage: Sharks

Reputation
Smiling, benevolent, human-friendly media darlings versus scowling, mindless, man-eating monsters and villains. The truth? Neither is accurate. Still, the advantage is clear
Advantage: Dolphins

Diversity
There are around 32 species of dolphins and porpoises. There are over 450 species of sharks, maybe as many as 480. Shark species come in an amazing array of shapes and sizes, from less than a foot to almost 50 feet.
Advantage: Sharks

Body Form
Dolphins have a sleek, streamlined shape with stiff fins for steering and a strong tail for propulsion. Perfect for life in the ocean. Too bad sharks had it figured out 385 million years earlier.
Advantage: Sharks

Skin
Dolphin skin is smooth, rubbery and good for biting. Shark skin is tough, elastic and covered with tiny teeth. It provides excellent protection from predators and aids in swimming by channeling water along the shark's body.
Advantage: Sharks

Reproduction
Dolphin embryos are nourished by the mother within her womb and then born live. Very advanced. Guess what? Sharks do it, too. Some species bear their young live and for a little variety, some others lay eggs.
Advantage: Sharks

Feeding styles
Dolphins use sound to locate their prey and may work together to capture it. Sharks will use teeth, tails, gill rakers, sound, smell, sight, lips, head and even electricity to find, catch and devour their food.
Advantage: Sharks

Intelligence
Dolphins are highly intelligent and highly trainable. Some have even been trained to retrieve unexploded mines by the Navy. You could never get a shark to retrieve anything referred to as "unexploded," so who's really smarter?
Advantage: Dolphins

Conservation Status
Dolphins may be protected in the U.S., but they're still hunted in other parts of the world. Several dolphin populations are dangerously low. Sharks are facing worldwide declines fueled by commercial fishing, bycatch and habitat loss.
Advantage: Dolphins

Seems the shark has many clear advantages over the dolphin.

Started by Taipan
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Mako shark kills dolphin - http://www.youtube.com/watch?v=8UB1aHaU0Lw

Accounts of GWS feeding on dolphins in the Mediterranean. http://www.youtube.com/watch?v=ZQHFDUbfBX8&feature=related; http://www.youtube.com/watch?v=Dp9pFlKAkzQ

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Shark Snacks On False Killer Whale


[blockquote]A false killer whale that beached on the Sunshine Coast yesterday bore wounds thought to be from a shark attack, experts have said.[/blockquote]
A National Geographic video showing a possible evidence of a shark attack on a Killer Whale:



Thanks to Scottwolverine1111 for finding this video.

A would like to see that how a (> 6 m) long great white shark would fare against a killer whale.
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Here's an oldie!

"Jaws -- 4 Million BC: How an Extinct Shark Attacked Its Prey

Date: March 17, 2010
Source: Wiley-Blackwell
Summary:
Palaeontologists have discovered evidence of how an extinct shark attacked its prey, reconstructing a killing that took place 4 million years ago.

Posted Image
Skeleton of the dolphin, preserved for 4 million years with the bite marks across its ribs from the shark attack the killed it.
Credit: Giovanni Bianucci

ScienceDaily (Mar. 17, 2010) — It might sound like a mashup of monster movies, but palaeontologists have discovered evidence of how an extinct shark attacked its prey, reconstructing a killing that took place 4 million years ago.

Such fossil evidence of behaviour is incredibly rare, but by careful, forensic-style analysis of bite marks on an otherwise well-preserved dolphin skeleton, the research team, based in Pisa, Italy, have reconstructed the events that led to the death of the dolphin, and determined the probably identity of the killer: a 4-meter shark by the name of Cosmopolitodus hastalis.

The evidence, published in the latest issue of the journal Palaeontology, comes from the fossilised skeleton of a 2.8-meter-long dolphin discovered in the Piedmont region of northern Italy.

According to Giovanni Bianucci, who led the study: "the skeleton lay unstudied in a museum in Torino for more than a century, but when I examined it, as part of a larger study of fossil dolphins, I noticed the bite marks on the ribs, vertebrae and jaws. Identifying the victim of the attack was the easy part -- it's an extinct species of dolphin known as Astadelphis gastaldii- working out the identity of the killer called for some serious detective work, as the only evidence to go on was the bite marks."

The overall shape of the bite indicated a shark attack, and Bianucci called in fossil shark expert Walter Landini. "The smoothness of the bite marks on the ribs clearly shows that the teeth of whatever did the biting were not serrated, and that immediately ruled out some possibilities. We simulated bite marks of the potential culprits and, by comparing them with the shape and size of the marks on the fossils, we narrowed it down to Cosmopolitodus hastalis."

Circumstantial evidence also supports this verdict: fossil teeth from Cosmopolitodus are common in the rock sequences that the dolphin was found in. "From the size of the bite, we reckon that this particular shark was about 4 m long" says Landini.

Detailed analysis of the bite pattern allowed the researchers to go even further. "The deepest and clearest incisions are on the ribs of the dolphin" says Bianucci, "indicating the shark attached from below, biting into the abdomen. Caught in the powerful bite, the dolphin would have struggled, and the shark probably detached a big amount of flesh by shaking its body from side to side. The bite would have caused severe damage and intense blood loss, because of the dense network of nerves, blood vessels and vital organs in this area. Then, already dead or in a state of shock, the dolphin rolled onto its back, and the shark bit again, close to the fleshy dorsal fin."

The study is significant because of the rarity of such 'fossilized behaviour'. According to Dr Kenshu Shimada, fossil shark expert at DePaul University and the Sternberg Museum of Natural History in the US, "studies like this are important because they give us a glimpse of the ecological interactions between organisms in prehistoric seas. Shark teeth are among the most common vertebrate remains in the fossil record, yet interpreting the details of diet and feeding behaviour of extinct sharks is extremely difficult. Fossil remains of prey species with shark bite marks, like those described by Bianucci and his team, provide direct evidence of what each prehistoric shark ate and how it behaved."

Story Source:
Wiley-Blackwell. "Jaws -- 4 million BC: How an extinct shark attacked its prey." ScienceDaily. www.sciencedaily.com/releases/2010/03/100316142519.htm (accessed January 28, 2013).




Journal Reference:
Giovanni Bianucci, Barbara Sorce, Tiziano Storai, Walter Landini. Killing in the Pliocene: shark attack on a dolphin from Italy. Palaeontology, 2010; 53 (2): 457 DOI: 10.1111/j.1475-4983.2010.00945.x

Abstract:
Shark bite marks, including striae, sulci and abrasions, in a well-preserved fossil dolphin skeleton referred to Astadelphis gastaldii (Cetacea, Delphinidae) from Pliocene sediments of Piedmont (northern Italy), are described in detail. The exceptional combination of a fossil dolphin having a significant part of the skeleton preserved and a large number of bite marks on the bones represents one of the few detailed documentations of shark attack in the past. Most bite marks have been referred to a shark about 4 m long with unserrated teeth, belonging to Cosmopolitodus hastalis, on the basis of their shape and their general disposition on the dolphin skeleton. According to our hypothesis, the shark attacked the dolphin with an initial mortal bite to the abdomen from the rear and right, in a similar way as observed for the living white shark when attacking pinnipeds. A second, less strong, bite was given on the dorsal area when the dolphin, mortally injured, probably rolled to the left. The shark probably released the prey, dead or dying, and other sharks or fishes probably scavenged the torn body of the dolphin.

http://onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2010.00945.x/abstract;jsessionid=51CD34D720D5FF9CD8149305843F0F34.f04t02
Edited by Taipan, Jan 3 2016, 01:42 PM.
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Is this video true?

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Offshore Orcas from the Northern Pacific hunt sleeper sharks in the depths



..which apparently does a great deal of damage to their teeth:


"Killer whales are notoriously picky eaters. Now one type of killer whale, or orca, has been found to dine on an unusual dish: shark. But these 'offshore' killer whales of the northeastern Pacific pay a high price for their tough-skinned preference — their teeth become worn right down to the gums."


"The diet of offshore killer whales -- first identified on the B.C. coast in 1989 -- has remained largely a mystery due to their wide-ranging and distant movements.

This latest study, newly published in the journal Aquatic Biology, proves through DNA evidence that offshore killer whales prey on large Pacific sleeper sharks, whose skin is so abrasive it is believed to be wearing the whales' teeth flat."



"Spotting the offshore orcas' fearsome feast took some doing. Ford's colleagues and contacts were able to observe the whales on 98 occasions from 1988 to 2009. But as they feed at depths of hundreds of metres, their actual dining habits were difficult to discover. The researchers only caught them hunting on two occasions: the fact that they were feeding was given away by their quick turns, long, deep dives, and the blobs of pink meat that floated to the surface. Genetic testing of these blobs confirmed the remains of at least 16 Pacific sleeper sharks (Somniosus pacificus)."

Sources:
http://www.calgaryherald.com/technology/Killer+whales+prey+sleeper+sharks/4123605/story.html
http://www.nature.com/news/2011/110120/full/news.2011.28.html






Shortfin Mako Shark v Two Orcas

Posted Image
Orcas eye a Mako shark, which they later killed and ate, in the Bay of Islands, New Zealand. This photo from the April 2005 National Geographic issue.

"In the Bay of Islands in 1998, an orca made a ferocious attack on a mako shark. Held by the tip of the tail, the shark tried to escape. It broke free to ‘hide’ under a boat, but the orca pursued it, bit it around the girth, and descended with the shark in its mouth, regrasping it near the tail. A second orca joined in the attack, biting the shark on the head, and together the two descended while eating their doomed victim."
http://www.teara.govt.nz/EarthSeaAndSky/SeaLife/Orcas/2/en

FERTL, D., BERGHAN, J. AND VAN MEURS, R. (2000) Killer whale (Orcinus orca) predation on a shortfin mako shark (Isurus oxyrinchus), in New Zealand waters. Aquatic Mammals 26(3): 229-231.




Shark Snacks On False Killer Whale
Tuesday, December 29, 2009 by Martin Brody No Comments and No Reactions

A false killer whale that beached on the Sunshine Coast yesterday bore wounds thought to be from a shark attack, experts have said.
The whale died after desperate efforts by up to 50 people who rushed to Twin Waters on a rescue mission. The 3.8 metre female was first spotted at 6:30AM south of Mudjimba Island.
Originally thought to be a pilot whale, it was later identified by an attending Australia Zoo rescue team as a “pseudorca crassidens” – a false killer whale.

Posted Image
Workers Attempt to Revive False Killer Whale

The rescue team brought the whale into the shallows to conduct the identification, and efforts then continued to save the distressed mammal, which was believed to be an adult.
The injured whale had a damaged dorsal fin and evidence of “superficial” shark bites.
The rescue efforts stretched well into the morning as volunteers and veterinarians fought to keep the stranded mammal alive.
Australia Zoo veterinarian Tim Portas conferred with Sea World veterinarians during the rescue efforts.
A rescue unit spokeswoman said staff and volunteers were able to move the large whale from the beach and transfer it to a truck for transport to the Australian Wildlife Hospital at Beerwah.
“Unfortunately, despite everyone’s best efforts, the whale did not survive,” she said. “It underwent a necropsy at Australia Zoo to identify the cause of the stranding. The full cause of the stranding will not be known until the pathology results are completed.”
Those involved in the rescue were said to be devastated over the death of the whale.
Sources said sightings of the extremely sociable false killer whales are not common on the Coast. They prefer deeper waters away from land.

http://www.fearbeneath.com/2009/12/shark-snacks-on-false-killer-whale/




Taipan
Jan 11 2012, 10:32 PM
From AquaOrca

Pictured: The moment a whale delivers a deadly 'karate chop' blow to a killer shark
By Daily Mail Reporter

Last updated at 2:48 PM on 27th November 2009

These incredible pictures demonstrate how orca whales use a 'karate chop' to stun and then finish off killer sharks.
In a rare battle of beasts these images show how several populations of skilled killer whales around the world have learned how to overcome huge sharks, that most animals give a wide berth.

Using a combination of superior brain power and brute force, the highly-intelligent orcas are able to catch and eat what many think of as the ocean's top predators.

Posted Image
Moments before the deadly blow. The raised fin is about to come crashing down like a karate chop on a shark (circled). It has been driven to the surface by the orca before this coup de grace

Posted Image
No escape. A killer whale with a Mako shark in its grasp. After stunning the shark, the orca grasps the dazed creature and flips it upside down. When sharks are quickly flipped upside down, they enter a paralysed state known as 'tonic immobility' - making for an easy meal

The notorious Great White and Mako are just two of at least nine species of shark known to be on the menu for some orca families.
Populations of orcas in territories across the globe - including New Zealand, Papua New Guinea and the Farallon Islands off America's West Coast - have devised a number of strategies with which to take down their mighty adversaries.
But to make sure they don't end up seriously injured when attacking such dangerous prey, the orcas spend years perfecting the various techniques and watching more experienced adults demonstrate how to do it properly.

'The most impressive strategy is the 'karate chop'," said expert Dr Ingrid Visser, 43, who has studied orca behaviour for 17 years.
'The orca will use its tail to drive the shark to the surface. They don't even touch it. Using an up-thrust of its tail it creates a vortex which pushes the shark up on the current they create with their movements.

'Once the shark is at the surface, the killer whale pivots and lifts its tail out of the water and comes down on top of it like a karate chop.'

Posted Image
An orca moving in on a mako shark in New Zealand waters. Other methods observed by scientists of whales attacking sharks include 'corralling', where groups of orcas circle a lone shark and ram it at the least dangerous opportunity, or stealthily approaching the shark from directly below and catching it off guard in a violent sneak attack at its underbelly

With the shark dazed, the orca grasps the dazed shark and turns it upside down - giving a mind-boggling impression that the killer whale understands shark biology. When sharks are quickly flipped upside down, they enter paralysed state known as 'tonic immobility' - making for an easy meal.

'It's not that the orca understands the physiology of the shark,' said Dr Visser, from Tutukaka, North Island, New Zealand.. 'But it does demonstrate that they understand the behavioural consequences of what will happen if they take a certain action.

'You don't need to understand how a car works in order to drive it. All you need to know is the individual behaviours that make the car go.

'In the same way, it seems the orcas that can do this have learned that if they turn the shark upside down, they don't fight back. They simply manipulate that to their advantage.'

Other methods observed by scientists include 'corralling', where groups of orcas circle a lone shark and ram it at the least dangerous opportunity, or stealthily approaching the shark from directly below and catching it off guard in a violent sneak attack at its underbelly.
'They always eventually turn the shark upside down," added Dr Visser. "At that point the shark cannot fight back, it has been a successful hunt and they can feed.'
She added: 'We don't think that the orcas are specifically making a decision to go out and hunt shark. The marine world can be a difficult place to find food. When there is an opportunity, an orca will take it.'
Dr Visser is a leading orca researcher and has pioneered several discoveries in orca behaviour. She was the first to record orcas hunting hammerhead and thresher sharks.

Read more: http://www.dailymail.co.uk/sciencetech/article-1231454/Killer-whales-Death-karate-chop-deadly-tactic-used-orcas-sharks.html#ixzz0aQCWHfJr
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Shark attacks on Atlantic spotted dolphins near the Bahamas

Date: August 4, 2014
Source: Wiley
Summary:
A new analysis on failed shark attacks on the approximately 120 Atlantic spotted dolphins that are residents of the waters near Bimini, The Bahamas, has found that a total of 14 dolphins (15 percent of 92 cataloged animals) showed some sign of shark attack, and a further 15 (16 percent) exhibited scars that could not conclusively be classified as shark induced or not.

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Photographs, taken on 5 May 2010, of an injury to a female S. frontalis, ID#087. A) Note the damage to left side and B) the uniform scars, on the right, just below the damaged dorsal fin, suggesting the possibility that as many as five of the shark’s teeth became embedded in the dolphin’s flesh.

AMarine Mammal Science analysis on failed shark attacks on the approximately 120 Atlantic spotted dolphins that are residents of the waters near Bimini, The Bahamas, has found that a total of 14 dolphins (15% of 92 cataloged animals) showed some sign of shark attack, and a further 15 (16%) exhibited scars that could not conclusively be classified as shark induced or not.
Of 14 the shark attacks, there was no difference in scars or wounds between the sexes, and there was no significant difference between the location of bodily scars and wounds. No shark-related injuries were observed on the head.
It is assumed that sharks will have a greater success rate if the softer, ventral side of a dolphin is attacked.
"This type of scar analysis has never been completed for spotted dolphins. It gives us insight into the predation pressure these dolphins might face from sharks in the area," said lead author Dr. Kelly Melillo-Sweeting.

http://www.sciencedaily.com/releases/2014/08/140804123230.htm




Journal Reference:
Kelly Melillo-Sweeting, Stephen D. Turnbull, Tristan L. Guttridge. Evidence of shark attacks on Atlantic spotted dolphins (Stenella frontalis) off Bimini, The Bahamas. Marine Mammal Science, 2014; 30 (3): 1158 DOI: 10.1111/mms.12082

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http://onlinelibrary.wiley.com/doi/10.1111/mms.12082/abstract;jsessionid=A21B2F20A748BE4C61B8AD87C99AFF56.f03t01?systemMessage=Wiley+Online+Library+will+be+disrupted+9th+Aug+from+10-2+BST+for+essential+maintenance.+Pay+Per+View+will+be+unavailable+from+10-6+BST.
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RojJones
Sep 21 2014, 05:16 AM
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Monster shark’s brutal attack on dolphin at Newcastle’s Burwood Beach

NEIL KEENE THE DAILY TELEGRAPH JANUARY 15, 2015 4:29PM SHARE

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A shark goes in for the kill on a dolphin just off Newcastle's Burwood Beach. Picture: Peter Lorimer

IT is a sight to send shivers down any swimmer’s spine — a large adult shark going in for the kill less than 50m from shore.

Daily Telegraph photographer Peter Lorimer captured the disturbing incident just off Burwood beach in Newcastle — a city still reeling from the presence of a 5m great white spotted daily since Saturday.

A 3.5m predator, probably a tiger shark, closed in on a dolphin before launching a deadly attack.

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A 3.5 metre shark goes in for the kill on a dolphin / Picture: Peter Lorimer

The great white has forced the closure of the city’s beaches for six days straight, but the Burwood beach tiger shark was causing concern yesterday.

Spearfishermen, flouting beach closures, waded into the water less than 200m away, apparently oblivious to the drama.

At first the pod of dolphins looked like any other but closer inspection revealed a straggler with a terrible bite out of its back and a shark in close pursuit. The dolphins initially circled their injured mate but as the shark moved in and the injured animal grew weaker they scattered.

After a few slow, wide circles the shark lunged, tearing another chunk of flesh from just above the dolphin’s tail.

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There was no feeding frenzy. Instead, the shark hung back, seemingly waiting until the dolphin died before moving in to feed.

Tiger sharks are generally found further north but a strong East Australian Current has pushed warm water further south this year, bringing tigers sharks and other tropical species with it.

Asked if targeted culling would be considered for individual troublesome sharks such as the one off Newcastle, the Department of Primary Industries said it was a matter for police because it was a public safety issue.

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Police said they would generally only get involved if a shark attacked a human.

Southern Cross University marine biologist Dr Daniel Bucher said he did not support indiscriminate culls but the targeting of a problem individual could be necessary.

“If you’ve got a shark that is a real and imminent danger and doesn’t want to leave an area, there might be a case for targeting that individual shark,” he said.

“But it’s such a rare event. If a shark is hanging around one particular area, yes it is a possibility that once it finds it can eat people it might start to hang around and shift its habits to take on a new reliable food source.

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There was nothing this life guard could do to save the dolphin. Picture by Peter Lorimer

“That’s one reason why, when there is an attack, they want to make sure the shark isn’t hanging around and they want to make sure it gets a bad experience of that area.”

“Generally, chasing it out of the area with boats would be enough of a bad experience for a shark to decide it wasn’t worth it.”

This has not worked with the Newcastle shark, which has remained despite efforts to herd it out to sea.

The monster — estimated to weigh 1700kg — was spotted again yesterday, also off Burwood beach, while another 3m specimen was seen in Newcastle harbour.

“It is now confirmed that (several) sharks are being sighted,” a council spokeswoman said.

Dr Bucher said most large sharks rarely hung around for long. “Most large sharks are quite nomadic because their food doesn’t just stay around in one spot,” he said.

The maximum size of great whites is debated but is thought to be about 6.4m and 3.3 tonnes.

http://www.adelaidenow.com.au/news/monster-sharks-brutal-attack-on-dolphin-at-newcastles-burwood-beach/story-fni6uok5-1227186978501?sv=1ab11ebd0644f550fb5d93e41997f3d9&net_sub_uid=104976987
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Great white shark 'slammed' and killed by a pod of killer whales in South Australia

Updated 47 minutes agoWed 4 Feb 2015, 4:25pm

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PHOTO: A pod of orcas in the process of killing a great white shark near the Neptune Islands. (ABC News)

Divers who witnessed a family pod of killer whales kill a great white shark in South Australia say it was "the title fight of all title fights".

The divers, who were off the coast of the Lower Eyre Peninsula, said they witnessed the attack during a shark cage diving trip to the Neptune Islands on Monday.

They said it involved a family group of orcas, including two calves.

Charter operator Matt Waller said the whales were launching themselves out of the water and slamming down upon the great white.

"If that's what we're seeing on the surface, then I can only imagine that under the surface you had other whales that were working to try and keep this shark up," he said.

"It never actually went down. It stayed on the surface and was trying to get away."

Mr Waller said it was the first time he had seen "two apex predators of the marine world" fight.

"It's like the title fight of all title fights," he said.

"People were crying. People were laughing. People were swearing. They were at the height of emotion."

Crew member and marine biologist Gina Dickinson said the shark was eventually killed under the surface but she could see the orca pod's "movements".

"They were teaching the young, rounding it up in order to attack," she said.

"The intelligence behind it was just fantastic.

"It was definitely the highlight of my career. Not much is probably going to top this."

A first for South Australia

South Australian Museum senior researcher Catherine Kemper said she had not heard of the behaviour occurring in SA, but would confer with international colleagues to find out more about orca behaviour.

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PHOTO: A pair of killer whales near the Neptune Islands in South Australia. (ABC News)

Mr Waller said attacks by orcas in other places in the world had resulted in sharks dispersing "far and wide" and had the potential to destroy the cage diving season.

"We would then be waiting for fresh new sharks to rock up in the bay and engage with our customers," he said.

"We'll only know once we go down there and we see whether there are still sharks around.

"I don't know that it will affect it that badly. It's been such a good season ... there is, in my opinion, more sharks around."

http://www.abc.net.au/news/2015-02-04/great-white-killed-by-killer-whales-in-sa/6069168
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Video of the above account:



Edited by Taipan, May 7 2015, 03:01 PM.
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Shin
Jul 15 2015, 01:36 AM
A dolphin with a chunk of its body missing after an attack by an eleven-foot shark has been captured in graphic photographs in the Australian city of Newcastle, where beaches remain closed for a record seventh day due to continued sightings of a growing group of deadly sharks.
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The attack occurred just 60 yards from shore and came as the council admitted that there was not merely one shark – “the biggest we've ever had” - lurking around the city’s beaches, but several of different species.
The attack on the dolphin was by a tiger shark, which took a chunk from the dolphin’s back and then lunged forward for a second bite to take a chunk out of its tale. The shark then reportedly hung back and waited for the dolphin to die before feeding on it.
But the main concern, which led to the closure of the city’s seven beaches, has been the presence of a 15-foot, 1.7-ton great white shark.
Rachel Kulk, a 22-year-old local surfer told The Newcastle Herald the shark was ‘‘as round as a car’’ with a fin ‘‘more than half the size of my surfboard’’.
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Several additional sharks have since been spotted and at least two dolphin carcasses have been found around the city, which is about 100 miles north of Sydney.
“It is now confirmed that [several] sharks are being sighted,” a Newcastle council spokeswoman said.
It is believed the sharks may be coming closer to shores across Australia this summer due to warmer water temperatures.
The government in the state of New South Wales has indicated it would only consider a cull if public safety is at risk.
Experts said a cull is probably unnecessary because large sharks need to move around to find new sources of food and are unlikely to remain in the same stretch of coast for an extended period.
“If you’ve got a shark that is a real and imminent danger and doesn’t want to leave an area, there might be a case for targeting that individual shark,” Dr Daniel Bucher, a marine biologist at Southern Cross University, told Sydney’s Daily Telegraph.
“But it’s such a rare event. If a shark is hanging around one particular area, yes it is a possibility that once it finds it can eat people it might start to hang around and shift its habits to take on a new reliable food source.”
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Dr Bucher said that chasing a shark out of an area by boat will often help to keep it away – but this has not happened with the sharks around Newcastle.
Barry Bruce, a marine scientist with the CSIRO, the national science agency, said the presence of a great white shark in Newcastle was not unusual because the area was “a well-known and well-published white shark nursery”.
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The latest attack occurred at a beach south of Sydney when Sam Smith, a 17-year-old, was bitten on the hand after he dived down to try to film a five-foot shark while spearfishing.
Smith was fishing with Luke Sisinni, who described the attack to the local Milton Ulladulla Times: “It spun around and started coming for him, so he stabbed it with his spear to try and scare it off, but it just went ballistic and bit him…. He came up screaming saying, ‘I got bit by a shark’.”
http://www.telegraph.co.uk/news/worldnews/australiaandthepacific/australia/11350158/Shark-attacks-teenager-off-Australian-beach.html
http://www.inquisitr.com/1757632/monster-shark-kills-dolphin-off-australian-beach/


pckts
Jul 15 2015, 02:26 AM
TFS, first attack I've seen caught on film.
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