SEALS AS PREY, THREATENED SEALS AND HUMANS

SEALS AS PREY

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Killer whale attacking a seal
Seals are fed on by sharks and killer whales. Sometimes pups are taken by foxes on land. In Namibia seal pups are sometimes taken by lions and jackals Great White's sometimes even eat elephant seals. Once a large great white found off of California was dissected, revealing large chunks of elephant seal inside its stomach, including a completely severed head.

Great whites like to stalk their prey from behind and below, and then attack, taking a massive bite and then waiting for their victim to bleed to death. They often sneak up on sea lions, seals and elephant seals from below and attack from behind. They usually take a powerful first bite underwater and the first indication on the surface is a large slick of blood. Minutes later, the victim appears on the surface with a large chunk missing. The shark thne appears and finishes it off.

Great whites have been observed shooting vertically upwards from a depth of 10 meters and knocking their prey right out of the water to stun it. Off South Africa great whites have been seen leaping five meters out of the water with a seal in their mouth. The impact stuns the prey and often leaves it with a chunk taken out it. The sharks then attack again or wait for their victims to bleed to death.

Great white sharks hunting for seals in waters off South Africa swim around three meters off the bottom in water that is 10 to 35 meters feet deep and wait up to three weeks before making a lightning quick strike from below on a seal at the surface. They sometimes swim with their teeth bared, apparently to warn off competitors for food or let other great whites know they are approaching too close to shark’s personal space. Tagged sharks in False Bay in South Africa, hunt seals when they are present at Seal Island but abandon the island when summer approaches---and the seals leave the island---and patrol close to shore, just beyond the breakers.

Great White Sharks Attack of Seals

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Great white shark
Peter Klimey of the University of California has videotaped more than 100 attacks by great white sharks of elephant seals, sea lions and harbor seals at the Farallon Island, a group of rock islets west of San Francisco. Recalling an attack of an 400 pound elephant seal, Klimley told Time magazine, "It was stunning. The shark ambushed the seal, then came back several times to take three or four bites out of it. I had never seen anything like it...The white shark is a skillful and stealthy predator that eats with both ritual and purpose." Klimley told Discover, "The sharks appear to attack from ambush. From a seal's perspective, the dark grey of the sharks' backs could blend almost perfectly with a rocky bottom, and heavy surf could further serve to obscure them. The area of the best attacks...is one that provides them with the best camouflage."

One of the best places to see great white sharks is offshore from Seal Island in False Bay, near Cape Town in South Africa. Large sharks are routinely seen here leaping from the water with seals in their mouths. The waters around Seal Island are a favorite feeding area for great white sharks. On the flat, rocky island, a third of a kilometer long, 60,000 Cape fur seals gather. The seals are often attacked in the morning as they leave the island for their feeding ground 60 kilometers out in the bay. The attacks generally occur in the hour after dawn, because, scientists think, after that time, the seals can see the sharks approaching them from underwater and can escape. In the morning the seals are often jittery. Shark expert Alison Kick told Smithsonian magazine, “They want to go to sea to feed but they’re afraid of the white sharks.”

Great white sharks begin attacking the seals minutes after the first ones leave Seal Island to go out to sea. Paul Raffaele wrote in Smithsonian magazine, “The attacks begin...A 3,000-pound great white explodes out of the water. In mid air the shark lunges at a seal and flips back into the water with a mighty splash, Moments later another shark breaches and bites a seal, We speed to the spot, in time to see a pool of blood. Scores of gulls hover above, screeching in excitement, they swoop down to gobble up any leftovers...During an hour and a half, we witness ten great white sharks hurtling out of the water to grab seals. As the rising sun brightens the sky, the attacks stop.”

Describing an attack on a seal pup, Adrian and Anne Martin wrote in Natural History magazine, “Suddenly a a ton of white shark launched from the water like a Polaris missile, the little seal clamped between his teeth...the shark clears the surface by an astonishing six feet. It hangs, silhouetted in the chill air for what seems like an impossibly long time before it falls back into the sea, splashing thunderous spray...Now mortally wounded and lying on its side at the surface, the seal raises its head and weakly wags its left foreflipper...The shark, an eleven-and-a-half-foot male. Circles back unhurriedly and seizes the hapless seal pup. He carries it underwater, shaking his head violently from side to side, an action that maximizes the cutting efficiency of his saw-edged teeth. An enormous blush stains the water and an oily, coppery smell of the wounded seal pricks our nostrils. The seal carcass float to the surface while gull gulls and other seabirds compete for its entrails.”

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Great White Sharks Strategy Killing Seals

A study by Neil Hammerschlag of the University of Miami published in the Zoology Society of London’s Journal of Zoology found that great white sharks at Seal Island don’t just go after their victims randomly but rather use methods similar to those used by serial killers. “There’s some strategy going on,” Hammerschlag, told AP. “It’s more than sharks lurking at the water waiting to eat them.” [Source: Seth Borenstein. AP, June 2009]

Hammerschalg observed 340 great white shark attacks of seals at Seal Island. He observed that the sharks had a clear mode of operation. They tended to stalk their victims from a distance of 90 meters, close enough to see their prey and far enough away so their prey couldn’t see them. They attacked when the light was low and sought victims that were young and alone. They liked to attack when no other sharks were present. Most of all the liked to surprise their victims, sneaking up from below, unseen.

Hammerschalg’s team analyzed the great white’s action using “geographic profiling,” a method used in criminology that looks for patterns in where criminals strike. They surmised that the sharks learned from previous kills by the fact that larger, older sharks had more success making kills than younger, inexperienced ones.

Polar Bears and Seals

Polar bear hunt seals. They wait for coastal waters to freeze on then live a solitary life of seal hunting. The bears often ignore the meat and gorge themselves on the fat, which they need for energy.

Polar bears mainly hunt seals using two methods: by stalking seals from land or underneath ice after they have emerged at breathing holes; or by waiting patiently near the seal's breathing hole and biting its head as it surfaces.

Polar bears are so strong they can reach in hole of ice, kill the seal with a single, crushing bite and then pull it out of the water its strong neck and shoulder muscles.

A favorite polar bear prey is seal pups that are born in the spring in little caves hollowed out of snow rifts by their mothers above their breathing holes in the sea ice. The seals are well hidden but the bears can locate the pups with their amazing sense of smell. The polar bears kill the pups with a bite to the head. The 50 pound animals are almost half fat.

Cannibalism Among Seals and Sea Lions

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Sea Lion trainer from
Space and Naval Warfare
Systems Center (SPAWAR)
Cannibalism has been observed among grey seals in Canada, elephant seals in Argentina and the New Zealand sea lion ( Phocarctos hookeri ). On the New Zealand sea lions, Adam Lusher wrote in the Electronic Telegraph, “Scientists who studied the population structure of a breeding colony at Dundas Island were amazed to see 47-stone males grabbing pups which weighed only about two stones, dragging them into the sea and devouring them. As the mothers called plaintively from the shore, the males bit off the pups' limbs and shook their bodies with such ferocity that the carcasses were hurled out of the water. [Source: Adam Lusher, Electronic Telegraph, October 2000]

Dr Ian Wilkinson, the biologist leading the study, said: "We were shocked. The male would come ashore, grab the pup, swim out 50 or 100 meters with it, shake it around, kill it, and then bite off chunks and limbs and eat them...When it was happening, we would see whole groups of seabirds gathering nearby. Then all of a sudden, you would see a pup come flying out of the water and watch the carcass splash down. It's never pleasant to see that sort of thing. I don't think anybody enjoys seeing animals kill other animals."

In 12 weeks, the scientists recorded 24 cases of cannibalism at Dundas Island, 200 miles south of New Zealand, where up to 300 pups are born every year. Eleven killings were witnessed during the first study period in early 1999 and a further 13 occurred in January and February of 2000. Dr Wilkinson, of the New Zealand Department of Conservation, said: "We saw the male grabbing the pups on two occasions. We saw them eating the pups in a further 22 cases. In one instance we saw the mother bite the male, who dropped the pup and bit her. He was twice or three times her weight. There was nothing she could do. When the male took the pup away, the mother called as she would when returning from a feeding trip. She sat on the rocks calling for about 25 minutes."

The New Zealand (or Hooker's) sea lion, is one of the rarest sea lion species in the world. Dr Wilkinson said the cannibal males could be killing about two per cent of a population of between 13,000 and 17,000. "It is not good for the species as a whole, but maybe it is a clever feeding strategy for the individual males involved. It is very difficult to speculate on why they do it. Maybe it's because the pups are an easy source of food. Normally they might have to swim out and dive to 300 or 400 meters to catch squid. But a single pup is enough to meet their daily needs for food, and they don't have to expend huge amounts of energy to get it."

Cannibalism is common in many other species, and has been recorded in at least 100 mammals, including man. Dr Wilkinson said: "There are several reasons for cannibalism. As well as killing for food, adults will kill unrelated young to increase their access to food or breeding sites for themselves and their offspring. A third reason is sexual selection, where males kill unrelated offspring. This is common in lions. When a male takes over a pride, he will often kill all the pups, because the females will then come into season and he can produce offspring of his own."

Seals, Sea Lions, Humans and the Military

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US Navy sea lions Shallow
Water Intruder Detection
System (SWIDS) program
Nearly all pinnipeds have been hunted at one time or another for their meat, oil, ivory or fur. Leather is sometimes made from seals. Some species are still pursued while others are protected.

In the Arctic the Inuit traditionally hunted seals by cutting a hole in the ice and waiting for a seal to show up. When a seal showed up it was harpooned. The Inuit ate the blubber and meat and used the skin for boots, clothing and cover for kayaks.

Commercial sealers traditionally drove the seals to a designated area and killed them with blow to soft parts for their skulls. Most of the animals caught to do tricks in marine animal shows are sea lions.

As of 2007, there were 25 California sea lions at the U.S. Navy facility at Point Loma, near San Diego which also has 74 dolphins. Sea lions are particularly valued because they have great vison in poor light, superior hearing capabilities and can maneuver in tight spots. They are used near piers and anchored ships. They have been trained to find swimmers, place clamps on their legs and take an attached line to sailors awaiting above. This method can be used to retrieve downed pilots or snag scuba-diving terrorists. Sea lions have also been trained to mark underwater objects.

Dolphins and sea lions are on duty in waters off the submarine base in Kings Bay, Georgia and were mobilized in the Persian Gulf in the war in Iraq in 2003. Sea lions employed by the United States Marine Mammal Program have been trained to swim up behind enemy divers and immobilize their legs with cuffing devises so people on the surface can haul them up by rope.

See Dolphins

Seal and Sea Lions Human Attacks

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US Navy sea lions Shallow
Water Intruder Detection
System (SWIDS) program
In September 2005, a sea lion mob sunk a sailboat in Newport, California. According to the Los Angeles Times 18 or more of the giant pinnipeds piled onto a 37-foot sailboat in Newport Harbor, near Los Angeles, and sank it. The Harbor Commission blamed the problem on an invasion of sea lions. The U.S. West Coast Sea Lion population is presently estimated to be between 300,000 to 400,000 animals. Marine biologist Doyle Hanan said, "it's a growing problem and it's going to continue to grow." [Source: Los Angeles Times]

In July 2005, a sea lion attacked a lifeguard in waters off Santa Barbara, California. Officials said the lifeguard was bitten three times while he swam about 50 yards offshore and needed about 30 stitches after the attack. In October 2005, a cape fur seal attacked woman and bite off her nose in South Africa. Cape fur seals are common on South African shores. This particular female "had been lying in the same spot since Friday, so the lady and a few other people were trying to take it back to the water.” In 2004 Anchorage Daily News in Alaska reported on attack on one person by a a 1200-pound sea lion.

In November 2006, a “bloodthirsty baby” sea lion went on a rampage and attacked 14 swimmers at San Francisco’s Aquatic Park, drawing blood from three of them. None of the injures were serious. One witness, who swims at the park daily, told the San Francisco examiner, “I “ve never seen anything like this, and I’ve been swimming here since I was a kid and I’m pretty old now. He said the seal rammed him and left him with a bruise, The last time he saw anything remotely like was 18 years before he said. The site was closed for a while.

In October 2010, a sea lion attacked a rowing crew in New Zealand’s Otago harbor, cracking the hull of the $30,000 vessel, One rower told AFP, “I saw this dark figure looming under the boat. I felt it hit and, seconds later, water came gushing up...it was panic stations. The crew then headed to the nearest boat ramp with sea lion in pursuit.

Leopard Seal Attacks

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leopard seal
The crew of the famous Shackleton expedition in 1914 had several encounters with leopard seals. Thomas Orde-Lees was skiing across an ice flow when a leopard seal emerged between two ice flows and lunged after him. Orde-Lees managed to escape only to have the seal track him from below the ice and attack again from ahead. Orde-Lees shouted for help. Another member of the expedition, Frank Wild, shot the leopard seal dead.

Describing close encounters with a leopard seal Paul Nicklen wrote in National Geographic, “I expected this 12-foot-log female to flee with her catch, a live penguin chick, but instead she dropped it on my camera. Then she opened her mouth and engulfed the camera---and most of my head. After 45 minutes of more threats, she finally relaxed and ate.” On another encounter he wrote, “In a lethal game of cat and mouse, the large female...caught and released this penguin chick...for more than an hour, repeatedly presenting it to me. When I ignored her, she blew a stream of bubbles from her nose in a threat display and tried again...More frightening than the canines of the large female was the deep jackhammer sound she let loose that rattled through my chest.”

Goran Ehlme, a Swedish cinematographer who has spent years with leopard seals, said their reputation for fierceness is somewhat undeserved. Mostly they are just inquisitive he said. “It makes a better story to tell about a ferocious animal than it does tell about a curious one,” he said. “People tend to judge animals in frightening moments. But these seals, they are mostly curious.” Even so Antarctic research stations advice anyone not doing research to stay out of the water if they sea a leopard seal.

Leopard Seal Kills a Biologist

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leopard seal
In July 2003, Kirsty Brown, a 28-year-old marine biologist, was snorkeling off the Antarctic Peninsula, when she was grabbed, pulled down and drowned by the leopard seal, her colleagues worked for an hour to revive her, but could not. There had been reports of leopard seals harassing people and puncturing inflatable boats but his was the first report of a human fatality by a leopard seal.

According to Reuters Brown was attacked by a leopard seal while she carried out research close to the Rothera research station, about 800 miles south of the Falkland Islands. Horrified colleagues watched as Brown, a qualified diver, was pulled underwater and drowned by the seal.

Professor Chris Rapley, director of the British Antarctic Survey (BAS), said Brown's death had shocked her colleagues. "In 30 years we have never experienced anything like this," a BAS spokesman told the Daily Telegraph newspaper. "Leopard seals are incredibly inquisitive, but are not normally aggressive. If a diver can see a leopard seal, then they will not go in the water because there is a small risk. But to our knowledge, this has never happened before."

Threatened Seals

"Humans have been killing seals for food since the Stone Age times, judging from ancient seal clubs and bones found along Denmark's Kattegat Strait," Roger Gentry wrote in National Geographic, "When an efficient way was found in the 1800s to rid fur seal hides of their outer guard hair, leaving only the soft durable underfur, millions of those animals were slaughtered for garments." Colonies of thousands of animals were exterminated in a few years. Today seals are mainly taken for "seal sticks," or penis bones, which are thought by some Asian cultures to be aphrodisiacs.

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Hooker's sea lion
Many seals are lost when they drown in fishing nets. Of the world's 5,000 Hooker sea lions, 75 females were accidently drowned in a single year. Sometimes seals will gather around fishing nets where they feast on the fish, much to the dismay of the fisherman who sometimes play killer whale sounds to try and get rid of them. Sometimes fisherman shoot the seals and or scare them with away with explosives.

There have been reports of seal beachings similar to those of whales and porpoises. On the east coast of the United States sick baby hood seals washed up on beaches in 2006. One was found eating sand. Hooded seals are usually only found in Arctic waters.

In the late 1990s the number of sick and malnourished sea lions, seals and elephant seals along the northern coast of California increased. No one was sure why. Some scientists thought it was a consequence of overfishing or some other disruption of the food chain that deprived these marine mammals of e food they were used to getting.

Seal Penises are sought after in Chinese Medicine as an aphrodisiac.

Seals as Pests and 90,000 Seals Clubbed in Namibian Seal Hunt

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Namibia holds an annual commercial seal hunt between July 1 and Nov. 15. In 2011, the hunt was held despite objections by animal welfare groups. Hunters are expected to club over 90,000 seals, including 85,000 pups.Namibia is one of only a few remaining countries with a commercial seal harvest. The government argues that the seal population needs to be controlled to protect fish stocks. However, animal rights activists say the practice is inhumane and outdated. [Source: Tawanda Kanhema The Times of London, July 7, 2011]

Seals are hunted for skins, fur and meat, and seal genitals are sold as traditional medicines and aphrodisiacs in Asia. Animal rights groups like Fur Free SA and a newly formed organisation, The Seals of Nam, have raised their voices in protest, objecting to the violent manner in which baby seals are clubbed to death during the culling operation, which ends with exports of pelts to Australia for use in the manufacturing of fur coats and local extraction of seal oil for industrial use.

Activist Francois Hugo of Seal Alert South Africa said last week that he had made a bid to buy out the company that purchases the Namibian seal pelts, effectively halting the hunt.Hugo said that clubbing an animal to death is cruel, criminal and in defiance of international animal protection laws. He also challenged the Namibian government's claim that the hunt maintained healthy seal populations, saying that in the past whole colonies had been devastated.

Namibia's seals number about 900,000 and live on a dozen remote, rocky islands off the coast of the sparsely populated southern African country. Several large colonies of seals lie south of Henties Bay, a major tourist destination and the mecca of Namibia’s fishing industry. The hunt takes place under clandestine circumstances to avoid the glare of publicity---and to avoid upsetting tourists. The government has said seals consume 900,000 tons of fish each year, more than a third of the fishing industry's catch, and that the cull is needed to protect fisheries. Animal welfare groups counter that most of the seals killed are still-nursing pups.

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seal clothes
AJ Cady of the International Fund for Animal Welfare said that the industry is "collapsing" worldwide, citing a recent European Union ban on the import of seal products combined with the global economic downturn. In this year's Canadian harvest, sealers killed less than a third of their quota on weak demand. "The great question here is who is really buying these things?" Cady said. "The cruelty is so obvious."

The Namibian government’s position on seal population control is largely influenced by fishing interests, and Esau said the harvesting of seals is meant to reduce competition for fish between fisheries and the seal population. The government claims that pilchard harvests have gone up since the culling of seals began.

Namibia’s Minister of Fisheries and Marine Resources, Bernard Esau, said his ministry had received complaints from Namibian fisheries, particularly holders of long-line fishing rights, that seals were consuming nearly half of their catch and unhooking nets from their fishing boats. “Long-line fishermen are faced with seals following their vessels and unhooking their catch from the fishing vessels,” Esau said, “There are a lot of complaints from our long line rights holders, more than 50 percent of their fish is being unhooked by seals. “There are close to a million seals in our waters and because the colonies have grown, we need to reduce this to a manageable population.”

The Namibian government estimates that seals consume 900,000 tonnes of fish a year, close to third of the fishing industry’s annual catch. Namibia’s fishing industry is the second largest contributor to the country’s GDP and ranks among 10 of the world’s largest fishing industries.

Seals Listed as Endangered Because of Global Warming Concerns

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In December 2010, the U.S. government on proposed listing two seals that depend on sea ice as threatened species because of the projected loss of ice from climate warming. The National Oceanic and Atmospheric Administration will seek to list ringed seals found in the Arctic Basin and the North Atlantic and two populations of bearded seals in the Pacific Ocean as threatened under the Endangered Species Act. [Source: AP, December 4, 2010]

Ringed seals are the main prey of polar bears, which were listed as threatened by the U.S. Fish and Wildlife Service in 2008. For ringed seals, the proposed listing also cites the threat of reduced snow cover. NOAA climate models were used to predict future sea ice conditions. The Center for Biological Diversity petitioned to list the seals in 2008 and later sued to force a decision on additional protections.

"We're pleased that NOAA is following the science and the law in recognizing the reality of what global warming is doing to the Arctic and its species," said Brendan Cummings, an attorney for the Center for Biological Diversity.

Ringed seals can live in completely ice-covered waters, using stout claws to dig and maintain breathing holes. Young ringed seal pups cannot survive in water. They are susceptible to temperature stresses until they grow a blubber layer and shed their lanugo, the white, wooly coat they're born with. Early breakup of sea ice threatens lairs during critical rearing periods when pups are too young to survive in water. Warming can expose lairs and make pups vulnerable to polar bears and Arctic foxes.

Ringed seals have a large population, Cummings said, but the entire population is dependent on sea ice, a habitat that is disappearing. "They're incredibly well-adapted to life in the Arctic, but what they're not adapted to is rain on snow and the lack of ice," Cummings said. There is little chance they can survive by simply abandoning ice and taking up residence on shore, he said."This is an animal that essentially never comes to shore," he said. "They evolved on the ice. Absent the ice, there's nowhere to go."

Bearded seals give birth and rear pups on drifting pack ice over shallow waters where prey is abundant.When females give birth, they need ice to last long enough in the spring and early summer to successfully reproduce and then molt, or shed and grown back their fur. "What we're seeing for them is a shrinkage of that ice season," Cummings said.

Image Sources: Wikimedia Commons, National Oceanic and Atmospheric Administration (NOAA)

Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, Yomiuri Shimbun, The Guardian, National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.

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© 2008 Jeffrey Hays

Last updated January 2012

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