The orca, or killer whale, is one of the best-known and most majestic whales in the sea. Belonging to the dolphin family, the killer whale is found in all the world's oceans and has been the subject of study by numerous animal researchers in recent decades. Orcas are unique mammals in the way they live, for example, in feeding and migration, as well as in the mother-offspring relationship. Besides being such an interesting animal, they are currently in danger of extinction. When most people think of killer whales, Shamu comes to mind; the first killer whale to successfully thrive in captivity, also the iconic symbol of SeaWorld parks. Since the rise of killer whale notoriety with SeaWorld, the development of better research techniques, such as satellite tagging, has become important in understanding many aspects of the species, as well as learning how to protect them. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Killer whales are usually found in pods, which are large groups that can range from ten to eighty members. Interestingly, each pod is a unique family made up of blood-related whales. When a calf is born in a pod, the mother cares for it closely as many calves die when they are very young due to disease, accidents, or even predators such as large sharks (Carwardine, 4). If the calf survives its first few years, it will remain in the pod for the rest of its life. Each pod has its own special language, or dialect in the believed complex way of communication between other killer whales, and all members of the pod are similar in appearance, although no two orcas are exactly alike (Carwardine, 4). Another distinctive feature of killer whales is their dorsal fin. Male orcas have a huge dorsal fin that can grow up to six feet, females, however, have a much smaller and more curved dorsal fin (Carwardine, 4). In comparison to their large fins, adult orcas can weigh anywhere from three to eleven tons, and male orcas average in length from twenty-three to twenty-seven feet, but can reach lengths of up to thirty-two feet, and female orcas average between twenty and twenty-two feet (Killer Whale, National Parks Conservation Association). Pods of killer whales have been recorded in virtually all major oceans and seas and in all open water habitat areas (Dahlheim et al., 1981). Although they have been spotted everywhere, their primary habitat is in the frigid waters of the polar regions, such as the Arctic and Antarctic (Carwardine, 4). Another characteristic of killer whales and all other members of the cetaceans, the group of animals that consists of whales, dolphins and porpoises that receive only a set of one hundred pointed and sharp teeth to capture and tear prey (Carwardine, 4 ). The orca appears to be an opportunistic feeder; the diet can vary from one region to another, based on age and sex classes and over the years (Kirkevold and Lockard, 47). The unusual prey list includes many types of fish, birds, other small cetaceans, sea lions, seals, electric rays, and shockingly also blue whales, great white sharks, and other killer whales (Kirkevold and Lockard, 47). Killer whales are known to work together when hunting, developing special techniques and skills for the different foods they hunt. In Antarctica, they work together throwing sleeping seals and penguins from ice floes into the waiting mouths of other pod members (Carwardine, 27). One of the most interesting methods of prey hunting is used by killer whales off the coast of Argentina on the beaches of Punta Norte,where several pods have learned to catch young elephant seals and sea lion pups in the shallow waters (Carwardine, 28). Whales scan the beaches for their target and, once they find a victim easy enough to catch, they rush towards the beach so quickly that they leap out of the water and onto the beach, giving their prey no time to escape (Carwardine , 29). Most whales and dolphins get into serious trouble when they become stranded in this way, but Punta Norte orcas grab their prey and then thrash back into the sea (Carwardine, 30). Another method of finding food underwater is the use of echolocation, in which whales make special clicking sounds and listen for bouncing echoes (Carwardine, 31). In 1997, perhaps one of the most impressive and incredible accounts of an orca's choice of food. It was when two whales off the coast of California's Farallon Islands attacked and killed a great white shark. Peter Pyle, a biologist who studied birds and sharks in the Farallon area, was the expert present when the strange event occurred (Turner, Showdown at Sea). Pyle recalled seeing two whales, later identified as belonging to a Los Angeles pod, attack the shark. After about five minutes, the liver had been stripped from the shark and was being enjoyed with gusto by the whales as the dead shark carcass sank (Turner, Showdown at Sea). The accident was more than strange. No one anywhere had ever recorded seeing a killer whale attack a great white shark. And then something even stranger happened: the sharks of the Farallones disappeared (Turner, Showdown at Sea). Many researchers have tried to understand why the orcas had targeted the shark for prey, and most have concluded that the behavior is virtually unique to the Los Angeles pod, a band of cetaceans so strange that a better nickname might be Odd Pod (Turner, Showdown at Sea). Since then, researchers have studied the relationship between orcas and sharks and have come to discover that, although humans fear the great white shark as a top predator, sharks may perceive their rank differently (Turner , Showdown at Sea). Despite numerous killer whale locations, the population has been declining over the past two decades. The surprising element that is mainly responsible for the decline in the number of whales lies in their availability of food. For example, schools of fish commonly preyed upon by killer whales have been minimized due to factors including degradation of spawning habitat, reduced ocean survival, and overfishing (Ford et al., 97 ). Temporarily closing fisheries to protect the whales' livelihoods became an option, eventually becoming a major problem with the fishing industry in decline. Another surprising discovery that poses a huge threat to killer whales was the discovery of dangerously high levels of PCBs and other contaminants in their blubber, a level high enough to classify them as one of the most polluted cetacean populations in the world (Ford et al. 98). As top predators in the food chain, orcas ingest a variety of human-made industrial pollutants through their diet (Ford et al., 98). The dangerous pollutants that spill into the sea every day from factories, farmland and cities threaten the health of whales, shorten their lifespans and make them more susceptible to disease. Fortunately, PCBs are no longer produced in North America, but the safety of stored PCBs is questionable, and it seems likely that pollutants will continue.