Wednesday, October 9, 2019
A Killer Whale Study
A Killer Whale Study Killer Whales The orca, or the killer, whale is one of the most well-known and most majestic of the sea. Belonging to the dolphin family, the killer whale is found all over the worlds oceans and has been the object of study by many animal researchers over the past few decades. Killer whales are unique mammals in the ways that they live, for example, feeding and migration, also the mother-child relationship. Apart from being such an interesting animal, they are currently endangered. 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 the SeaWorld parks. Since the killer whales early notoriety with SeaWorld, the development of better researching techniques, such as satellite tagging, have become important in understanding many aspect of the species, as well as learning how to protect them. Killer whales are usually found in pods, which are large groups that can range anywhere from ten to eighty members. Interestingly enough, each pod is a unique family consisting of blood related whales. When a calf is born into a pod, the mother cares for it closely for many calves die when they are very young from illness, accidents, or even predators such as large sharks (Carwardine, 4). If the calf survives its early 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 and complex way of communication among other killer whales, and all members of the pod are similar in appearance, even though no two orcas look exactly alike (Carwardine, 4). Another distinguishing feature of killer whales is their Dorsal fin. Male killer whales 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 whale s can weigh from three to eleven tons, and male orcas grow to an average length of 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 oceans and major seas and from all open-water habitat zones (Dahlheim et al., 1981). Although they have been spotted all over, their primary habitat is in the freezing cold waters of the polar regions, for example the Arctic and Antarctic (Carwardine, 4). Another characteristic of killer whales and all other members of the cetaceansthe group of animals that consists of whales, dolphins, and porpoisesis that they only receive one set of a hundred teeth that are pointed and sharp for catching and tearing prey (Carwardine, 4). The killer whale appears to be an opportunistic feeder; diet may vary from one region to the next, among age and sex classes, and within years (Kirkevold and Lockard, 47). The unusual list of prey includes many types of fish, birds, other small cetaceans, sea lions, seals, electric rays, and outrageously even blue whales, great white sharks, as well as other killer whales (Kirkevold and Lockard, 47). Killer whales are known to work together while hunting, developing special techniques and skills for different foods that they hunt. In the Antarctic, they work together by tipping sleeping seals and penguins from ice floes into the waiting mouths of other members of the pod (Carwardine, 27). One of the most interestin g methods of hunting prey is used by killer whales off the coast of Argentina on the Punta Norte beaches, where several pods have learned how to catch young elephant seals and sea lion pups in the shallows (Carwardine, 28). The whales survey the beaches for their target and once they have found a victim easy enough for them to catch, they rush toward the beach so fast that they surge out of the water and onto the beach, leaving their prey no time to escape (Carwardine, 29). Most whales and dolphins are in serious trouble when they strand like this, but the killer whales of Punta Norte grab their prey and then wriggle back into the sea (Carwardine, 30). Other methods of finding food underwater is using Echolocation, where the whales make special clicking sounds and listen for the echoes that bounce back (Carwardine, 31). In 1997, possibly one of the most impressive and incredible accounts of an orca whales choice in food was when two whales off the coast of Californias Farallon Islands attacked and killed a great white shark. Peter Pyle, a biologist who studied the birds and sharks of the Farallon area, was the expert on hand when the strange event unfolded (Turner, Showdown at Sea). Pyle recalled seeing two whales that were later identified as belonging to an L.A. pod, attacking the shark. After about five minutes, the liver had been ripped out of the shark and was tastefully being enjoyed by the whales as the carcass of the dead shark sank (Turner, Showdown at Sea). The incident was beyond odd. No oneanywherehad ever recorded seeing a killer whale attack a great white. And then something even stranger happened: The sharks of the Farallones vanished (Turner, Showdown at Sea). Many researchers have tried to understand why the killer whales had targeted the shark as prey, and most have concluded that the behavior is pretty much unique to the L.A. pod, a cetacean gang so strange a better moniker might be the Odd Pod (Turner, Showdown at Sea). Since then, researchers have studied the relationship between killer whales and sharks and have come to find that even though humans fear the great white shark as the ultimate predator, sharks may perceive their rank differently (Turner, Showdown at Sea). Despite the many locations of killer whales, the population has been declining over the past two decades. The surprising element that is mostly to blame for the decline in whale numbers is found in their food supply. For example, schools of fish that are commonly preyed upon by orcas have been minimized due to factors, including degradation of spawning habitat, reduced ocean survival, and over-fishing (Ford et al., 97). Temporary closures of fisheries to protect the whales livelihood became an option, until it became a major problem with the declining fishing industry. Another startling discovery posing a huge threat to the killer whales was finding dangerously high levels of PCBs and other contaminants in their blubber, a high enough level to rank them as one of the worlds most polluted cetacean populations (Ford et al. 98). As top-level predators in the food web, killer whales ingest a variety of human-made industrial pollutants through their diet (Ford et al., 98). The dangerous p ollutants that pour into the sea every day from factories, farmland and towns threaten the health of the whales and shorten the life-span and leave them more susceptible to disease. Fortunately, PCBs are no longer produced in North America, but the security of the stored PCBs is questionable, and it seems likely that the pollutants will continue to seep into the whales habitat for years to come unless serious international efforts are made to eliminate them (Ford et al., 99). Although pollution and deterioration of food sources are key factors in the decline of killer whale populations, there are still other small factors, such as, incidents where whales are harmed or killed by boat propellers and even oil spills. The protection of these animals is necessary for their current status is endangered in some areas such as off the coasts of North America, and threatened in others. There are many aspects that make the killer whale such a defining beauty of the sea. First, their high intelligence level and well developed systems of communication set them apart from many animals. Then the culture they express commonly with family pods and strategized group hunting classifies them as a much more advanced species. Finally, the evolutionary domination of the seas as a high ranked animal of the food pyramid only remarks them as an incredible animal. There are many different species of the sea with many different characteristics that make them interesting, but none are as truly amazing as the killer whale. With laws in place to further protect the populations of killer whales many hope to see them prosper and live on for many centuries to come.
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